[Tutor] video watermark
Hi everyone. Can someone suggest a python module so that it would be able to do a video processing and adding watermark in video? -- "If it's not loud, it doesn't work!" -- Blank Reg, from "Max Headroom" ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misc question about scoping
"Steven D'Aprano" wrote isThumbnail = True if size == "thumbnail" else False That is technically correct, you could do that. That's a good example of the syntax of the `if` expression, but it's a bad example of where to use it: In the sense that an equality test will always give a real boolean value as a result I agree. But in the more generic case where we use an expressiioon as a boolean it can be usful. Specifically if the test involves boolean operators Python does not return True/False but the values of the operands. In that case using the if/else form yields a real boolean result. eg flag = True if (smoeValue or another) else False is different to flag = someValue or another Which was why I thought it worth pointing out that the if/else could be used. with all due respect to Alan who suggested it. It really is an unnecessarily complicated and verbose way of doing a simple assignment, In the case of an equality test I agree. -- Alan Gauld Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] sockets, servers, clients, broadcasts...?
On Thu, 3 Jun 2010 18:03:34 -0400 Alex Hall wrote: > Hi all, > I am a CS major, so I have had the required networking class. I get > the principles of networking, sockets, and packets, but I have never > had to actually implement any such principles in any program. Now I > have this Battleship game (not a school assignment, just a summer > project) that I am trying to make playable over the internet, since I > have not written the AI and playing Battleship against oneself is > rather boring. > > Right now I am just trying to figure out how to implement something > like the following: > *you start the program and select "online game" > *you select "server" or "client" (say you choose "server") > *somehow, your instance of the program starts up a server that > broadcasts something; your enemy has selected "client", and is now > (SOMEHOW) listening for the signal your server is broadcasting > *the signal is picked up, and, SOMEHOW, you and your opponent connect > and can start sending and receiving data. > > First, how does the client know where to look for the server? I am not > above popping up the server's ip and making the client type it in, but > a better solution would be great. > How do I make it so that the client can find the server correctly? The > above IP is one thing, but are ports important here? Not a big deal if > they are, but I am not sure. Does someone have an example of this > process? I'm far to be a specialist in this field, so this is just reasoning by watching your requirements. First, such a game seems to match peer-to-peer relation. This would be different if you implemented complicated game logic, like in the case of an AI playing. For peers to connect, a general solution is them to register on a dedicated public interface (the same can be used to publish a server's IP, indeed). Then, your app first reads data there to know which (address,port) pair(s) are available. But since you seem to be still exploring data exchange issues, you'd better concentrate on this basic mechanism first, choose and try one of numerous possible solutions, then only address higher-level problems. In the meanwhile, just put IPs and ports in a config file or even hardcode them as constants. About client-server, as said above, this model does not really seem to match your use case, I guess. But this is still an interesting alternative. I would set my own post as server and players as clients. So, when playing myself, I would be a local client. This indeed allows two other guys playing using your post as server (and you maybe watching the game ;-). But this does not make much sense if the server does not have any relevant info to deliver (eg playing hints). Denis vit esse estrany ☣ spir.wikidot.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] BerkeleyTIP Join June Global Free SW HW Culture Mtgs via VOIP or in Berkeley
Hi Python Tutor people :) Who leads this group? I put together a global meeting (via voip) that 1) has an interest in Python, 2) and that Python learners, users & developers might be interested in. BerkeleyTIP is a meeting about All Free SW HW & Culture. It is Educational, Productive, & Social. For Learning about, Sharing, & Producing, All Free SW HW & Culture. TIP == Talks, Installfest, Project & Programming Party http://sites.google.com/site/berkeleytip I put these meetings together in my nonexistent "free" time, as a volunteer contribution to the various communities. When i can make the time, I send out one announcement per month with the monthly videos to various free SW HW & Culture groups. Would you all would like to have me send your list the monthly announcements about the global via VOIP Free SW, HW & Culture meetings, BerkeleyTIP global? Please let me know. :) Below is the June announcement, so you know what they are like. We have a python video this month, too: Scientific data visualization using Mayavi2, Gael Varoquaux, Python4ScienceUCB Best wishes :) = You're invited to join in with the friendly people at the BerkeleyTIP global meeting - newbie to Ph.D. - everyone is invited. Get a headset & join using VOIP online, or come to Berkeley. 1st step: Join the mailing list: http://groups.google.com/group/BerkTIPGlobal Watch the videos. Discuss them on VOIP. 8 great videos/talks this month - see below. Starting off year 3 of BerkeleyTIP :) Join with us at the LOCATION TO BE DETERMINED at the University of California at Berkeley, or join from your home via VOIP, or send this email locally, create a local meeting, & join via VOIP: Tip: a wifi cafe is a great place to meet. :) JUNE 5 & 20 AT UCB MEETING LOCATIONS TO BE DETERMINED. PLEASE VIEW THE BTIP WEBSITE & MAILING LIST PAGES FOR THE LATEST DETIALS. http://sites.google.com/site/berkeleytip http://groups.google.com/group/BerkTIPGlobal BerkeleyTIP - Educational, Productive, Social For Learning about, Sharing, & Producing, All Free SW HW & Culture. TIP == Talks, Installfest, Project & Programming Party http://sites.google.com/site/berkeleytip = CONTENTS: 1) 2010 JUNE VIDEOS; 2) 2010 JUNE MEETING DAYS, TIMES, LOCATIONS; 3) LOCAL MEETING AT U. C. Berkeley LOCATION TO BE DETERMINED; 4) HOT TOPICS; 5) PLEASE RSVP PROBABILISTICALLY, THANKS :) ; 6) INSTALLFEST; SPECIAL: FREE 7th Annual BERKELEY WORLD MUSIC FESTIVAL June 5 Sat; 7) ARRIVING FIRST AT THE MEETING: MAKE A "BerkeleyTIP" SIGN; 8) IRC: #berkeleytip on irc.freenode.net; 9) VOIP FOR GLOBAL MEETING; 10) VOLUNTEERING, TO DOs; 11) MAILING LISTS: BerkeleyTIP-Global, LocalBerkeley, Announce; 12) ANYTHING I FORGOT TO MENTION?; 13) FOR FORWARDING === = 1) 2010 JUNE VIDEOS Super Computing for Business, Brian Modra, CLUG State of the Linux Union 2010, Jim Zemlin, Linux Foundation Journaled Soft-Updates, Dr. Kirk McKusick, BSDCan 2010 Scientific data visualization using Mayavi2, Gael Varoquaux, Python4ScienceUCB Bringing OLPC to children in Afghanistan, Carol Ruth Silver, OLPC-SF Text-to-Speech in Ubuntu with Kttsd Kmouth Festival, blip.tv Rabbi Rabbs, the UnixRabbi, leads a group of Unix geeks, Comedy, UUASC, BS"D, 2003 The Great Debate - Are We Alone?, Geoff Marcy and Dan Werthimer, s...@uc Berkeley Thanks to all the speakers, organizations, & videographers. :) [Please alert the speakers that their talks are scheduled for June for BTIP (if you are with the group that recorded their talk), because I may not have time to do that. Thanks. :) ] URLs for video download & full details: http://sites.google.com/site/berkeleytip/talk-videos Download & watch these talks before the BTIP meetings. Discuss at the meeting. Email the mailing list, tell us what videos you'll watch & want to discuss: http://groups.google.com/group/BerkTIPGlobal Know any other video sources? - please email me. _Your_ group should video record & post online your meeting's talks! = 2) 2010 JUNE MEETING DAYS, TIMES, LOCATIONS In person meetings on 1st Saturday & 3rd Sunday, every month. June 5 & 20, 12N-3P USA-Pacific time, Saturday, Sunday Online only meeting using VOIP: June 14 & 29, 5-6P USA-Pacific time, Monday, Tuesday Mark your calendars. 5 Sat 12N-3P PDST = 3-6P EDST = 19-22 UTC 14 Mon 5-6P PDST = 8-9P EDST = 0- 1 UTC Tues 15 20 Sun 12N-3P PDST = 3-6P EDST = 19-22 UTC 29 Tues 5-6P PDST = 8-9P EDST = 0- 1 UTC Wed 30 USA-PacificDaylightSavingsTime is -7 hours UTC, due to daylight savings currently. Times listed above should be double checked by you for accuracy. = 3) LOCAL MEETING AT U. C. BERKELEY - LOCATION TO BE DETERMINED http://sites.google.com/site/berkeleytip/directions RSVP please. See below. It greatly helps my planning. But, _do_ come if you forgot to RSVP. THE JUNE 5 & 20 ON CAMPUS MEETING LOCATIONS ARE CURRENTLY TO BE DETERMINED. HOPEFULLY KN
Re: [Tutor] Misc question about scoping
Alan Gauld wrote: flag = True if (smoeValue or another) else False is different to flag = someValue or another Which was why I thought it worth pointing out that the if/else could be used. I'd prefer the form: flag = not not (someValue or another) if I needed real True or False result. DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misc question about scoping
> That is technically correct, you could do that. That's a good example of
> the syntax of the `if` expression, but it's a bad example of where to
> use it:
>
> (1) it only works in Python 2.5 or better; and
>
> (2) experienced Python programmers will laugh at you :)
>
> with all due respect to Alan who suggested it. It really is an
> unnecessarily complicated and verbose way of doing a simple assignment,
> nearly as bad as writing this:
>
> if len(mystring) == 0:
> n = 0
> else:
> n = len(mystring)
>
>
> instead of just
>
> n = len(mystring)
>
>
Hey Everybody,
Thank you for the rich discussion and making me a better
python programmer! Between the new topics that I have learned in
Python and Django from documentation, experimentation, and this list,
I think my IQ has gone up a couple of points!
I'm at a point where I can do most things in Python (maybe) ,
now I'm looking to do them succinctly and elegantly. For instance, I
had about 10 - 15 lines of code to do this before with a bunch of
loops and if blocks, I distilled the product down to this:
answerDict=dict(map(lambda x: (str(x[1]),x[0]),map(lambda x: \
x.values(),Answer.objects.filter(fk_questionSet=1). \
filter(fk_question=1).values('widgetAnswer').order_by(). \
annotate(widgetCount=Count('widgetAnswer')
So instead of my python code doing the "leg work", I have the Django
ORM and that underlying DB do the work. Also, I leveraged lambda
functions and maps to coerce the data in to the right format. Pretty
cool IMHO. And I turn it over to the group to see if there is any
improvements or gotchas that I missed.
Thanks and Thanks in advance,
Tino
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Re: [Tutor] Misc question about scoping
On Fri, Jun 4, 2010 at 1:23 PM, Dave Angel wrote: > > I'd prefer the form: > > flag = not not (someValue or another) > That's a construct you might commonly find in languages like C, but I don't think it's very pythonic. If you want to convert your result to a bool, be explicit about it: flag = bool(some_value or another) I'd agree that the if/else construct is redundant if you just want a True/False result, but the double not is a kind of implicit type conversion that is easily avoided. Hugo ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misc question about scoping
On Fri, Jun 4, 2010 at 2:46 PM, Tino Dai wrote:
>
> I'm at a point where I can do most things in Python (maybe) ,
> now I'm looking to do them succinctly and elegantly. For instance, I
> had about 10 - 15 lines of code to do this before with a bunch of
> loops and if blocks, I distilled the product down to this:
>
> answerDict=dict(map(lambda x: (str(x[1]),x[0]),map(lambda x: \
> x.values(),Answer.objects.filter(fk_questionSet=1). \
> filter(fk_question=1).values('widgetAnswer').order_by(). \
> annotate(widgetCount=Count('widgetAnswer')
>
I have a distinct feeling that you would simply love a language like lisp.
> So instead of my python code doing the "leg work", I have the Django
> ORM and that underlying DB do the work. Also, I leveraged lambda
> functions and maps to coerce the data in to the right format. Pretty
> cool IMHO. And I turn it over to the group to see if there is any
> improvements or gotchas that I missed.
>
The code is succinct, and it may very well be called elegant in some
sense of the word. I might call it "clever," which in the python
community is not generally meant as a compliment. Readability counts,
you see, and I find that piece of code nigh impossible to read. I
would suggest changing the map calls into generator expressions, and
using a few temporary variables for clarity. That should keep most of
the brevity but increase legibility:
answers = Answer.objects.filter(fk_questionSet=1,
fk_question=1).values('widgetAnswer')
answers = answers.order_by().annotate(widgetCount=Count('widgetAnswer'))
values = (x.values() for x in answers)
answerDict = dict((str(v[1]), v[0]) for v in values)
Disclaimer: i'm not particularly experienced with django, so this
piece of code is quite possibly not the most efficient way to do this,
and may even be incorrect (e.g. I assumed the filter calls could be
collapsed like in sqlAlchemy). However, the rest of my advice should
still apply.
Hugo
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Re: [Tutor] video watermark
Am 04.06.2010 09:21, schrieb Igor Nemilentsev: Hi everyone. Can someone suggest a python module so that it would be able to do a video processing and adding watermark in video? Once I had to blur the part of the viewing area of a screencast which showed some confident CAD model. First, I exported the video as sequence of images with virtualdub. The result was something like 3000 *.bmp files on my harddrive. Then I created a little python script using PIL (http://www.pythonware.com/products/pil/). That script processed the files file by file, so no worries about huge movie files and memory. Finally, I've merged the new images with virtual dub. It all worked very well. Otherwise I'm not aware of any video processing library in Python. Also, there're filters for virtualdub to add watermarks to a movie. That might be the easiest way to get your results. Cheers, Jan ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misc question about scoping
> I have a distinct feeling that you would simply love a language like lisp.
LOL, it's actually on the list of things to do. And hear that one will become a
better programmer once they learn LISP.
> The code is succinct, and it may very well be called elegant in some
> sense of the word. I might call it "clever," which in the python
> community is not generally meant as a compliment. Readability counts,
> you see, and I find that piece of code nigh impossible to read. I
> would suggest changing the map calls into generator expressions, and
> using a few temporary variables for clarity. That should keep most of
> the brevity but increase legibility:
>
> answers = Answer.objects.filter(fk_questionSet=1,
> fk_question=1).values('widgetAnswer')
> answers = answers.order_by().annotate(widgetCount=Count('widgetAnswer'))
> values = (x.values() for x in answers)
> answerDict = dict((str(v[1]), v[0]) for v in values)
I am always fighting the battle - more compact vs more readable :) . A couple of
questions that I have: Why generators over map? Is it somehow more efficient
under the covers or is it for readability purposes? I noticed that you
took out the
lambda function too (not much good without a map/filter/reduce) to replace
with the generator function. Also could you give me some instances
where a generator
would be used in a real situation? I have already read the stuff on
doc.python.org about
generators.
Thanks,
Tino
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Re: [Tutor] Misc question about scoping
On 6/4/2010 5:46 AM Tino Dai said...
I'm at a point where I can do most things in Python (maybe) ,
now I'm looking to do them succinctly and elegantly. For instance, I
had about 10 - 15 lines of code to do this before with a bunch of
loops and if blocks, I distilled the product down to this:
answerDict=dict(map(lambda x: (str(x[1]),x[0]),map(lambda x: \
x.values(),Answer.objects.filter(fk_questionSet=1). \
filter(fk_question=1).values('widgetAnswer').order_by(). \
annotate(widgetCount=Count('widgetAnswer')
The first time there's a suspected problem with this code, you'll
probably end up with a similar refactored set of 10-15 lines. I'm sure
because I've got code like that scattered throughout my codebase and
that's what I end up doing. The difference is that I rattle off the
one-liners as part of the original coding effort, and only break it out
when there's a need to -- I'm not striving to compact things into
one-liners.
BTW, doesn't
dict(map(lambda x: (str(x[1]),x[0]),map(lambda x:x.values()
simply map the values of a dict back into a dict?
Emile
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[Tutor] treeTraversal, nested return?
All, any observations might be helpful. For the display of database contents I have the following problem: Database querys will return data to me in tuples of the following sort: each tuple has a unique id, a parent id, and a type. a parent id of 0 indicates that the element has no parent. not all data elements have children image elements have no children and must have a parent So the contents of the db is a tree of sorts: (1, 0, work) (555, 1, image) (556, 1, work) (557, 556, image) (558, 556, work) (559, 558, image) (560, 558, work) (561, 556, image) (562, 556, image) (563, 1, work) (564, 563, work) (565, 1, work) I have a function that will traverse this tree, summoning lists of tuples at each leaf. Well and good; it took a lot of trial and error, but it was a fine education in tree traversal. def makeHeirarchy(id): id = parentPath(id)[-1] rootimages = getImages(id[0]) rootworks = getWorks(id[0]) heirarchy = treeTraversal(rootworks, [id, rootimages]) return heirarchy ## which calls this recursive function: def treeTraversal(listIn,result): for x in listIn: if not getWorks(x[0]): result.append(x) result.append(getImages(x[0])) else: result.append(x) result.append(getImages(x[0])) treeTraversal(getWorks(x[0]), result) return result My problem is that this returns the tuples to me in a flat list. I've been trying to work out how I can get it to return some sort of nested structure: nested lists, dictionaries, or html thus: 1,0,data 555, 1, image 556, 1, data 557, 556, image 561, 556, image 562, 556, image 558, 556, data 559, 558, image 560, 558, image 563, 1, data 564, 563, data 565, 1, data ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] From SQL Blobs to Python Buffers to Actual Files
When I write the blob/binary data to a file and give it its original file name
"customer1.rtf", I am expecting the application to read the binary data into
text,excel,word documents, or whatever application created the file originally.
Example:
when I write blob1 to customer1.rtf, I get
"xÚµVKsÛ6î93ù{ÈÁîÈ2%Û±cŸlgœdÒ<&vLJ²\J¨" as my first line.
To get the blob in Python, I use the following:
row=cursor.execute("select top 1 * from FOO..DocUploads").fetchone()
#row[2] is the original file name, row[3] is the binary data
The blob, when selected in python is a buffer:
>>> row[3]
When I print row[3] I get data like "xڵVKsÛ6î93ù{ÈÁîÈ2%۱"
When I print str(row[3]) I get the same data.
From: Steven D'Aprano
To: tutor@python.org
Sent: Thu, June 3, 2010 9:18:44 PM
Subject: Re: [Tutor] From SQL Blobs to Python Buffers to Actual Files
On Fri, 4 Jun 2010 10:57:07 am GoodPotatoes wrote:
> I have been given a legacy database, and need to read the binaryfiles
> out to a disk. The table has columns "filename" and "binaryFile",
> where the binaryFile is a BLOB
>
> My python script so far is:
>
> import pyodbc
> cnxn=pyodbc.Connection("DSN=sybasedatabase")
> cursor=cnxn.cursor()
> p=cursor.execute("select top 1 * from FOO..Table").fetchone()
> #p contains ('UsersOldFile.rtf', size 1496, offset 0 at 0x010C04E0>)
>
> #I tried to write this out to the disk as:
> myfile=open(p[0],'wb')
> myfile.write(p[1])
> myfile.close()
>
> #but all I get is gibberish. Is there another way to handle the
> buffer, or something else I'm missing?
What do you mean "gibberish"? I would expect a binary blob to look
exactly like random binary characters, in other words, gibberish, so
what makes you think this is not working perfectly?
What do you get if you print the binary blob, and what do you expect to
get?
--
Steven D'Aprano
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Re: [Tutor] treeTraversal, nested return?
In general, there's 2 solutions to your "unflattening" problem.
A) The general solution: Keep track of the depth you're at, and add
tabs/spaces ('\t' * depth) as necessary.
B) The xml solution: Use (for example) the dom.minidom module, and create a
new "ul node" and populate it with children, at each level. Then, have the
xml do the printing for you.
For what it's worth, I may have a slight nit-pick of your final output. I
don't believe you can technically have a child of a node. I'm not
absolutely sure on that, but my quick google searching has appeared to
confirm. If that turns out to be true, you'll need to change the structure
of your output.
1,0,data
555,1,image
...
All of that is, of course, null and void if you define your own xml scheme.
--
I enjoy haiku
but sometimes they don't make sense;
refrigerator?
On Fri, Jun 4, 2010 at 11:15 AM, wrote:
> All,
>
> any observations might be helpful. For the display of database contents I
> have the following problem:
>
> Database querys will return data to me in tuples of the following sort:
> each tuple has a unique id, a parent id, and a type.
>
> a parent id of 0 indicates that the element has no parent.
> not all data elements have children
> image elements have no children and must have a parent
>
> So the contents of the db is a tree of sorts:
>
> (1, 0, work)
> (555, 1, image)
> (556, 1, work)
> (557, 556, image)
> (558, 556, work)
> (559, 558, image)
> (560, 558, work)
> (561, 556, image)
> (562, 556, image)
> (563, 1, work)
> (564, 563, work)
> (565, 1, work)
>
> I have a function that will traverse this tree, summoning lists of tuples
> at each leaf. Well and good; it took a lot of trial and error, but it was a
> fine education in tree traversal.
>
> def makeHeirarchy(id):
>id = parentPath(id)[-1]
>rootimages = getImages(id[0])
>rootworks = getWorks(id[0])
>heirarchy = treeTraversal(rootworks, [id, rootimages])
>return heirarchy
>
> ## which calls this recursive function:
>
> def treeTraversal(listIn,result):
>for x in listIn:
>if not getWorks(x[0]):
>result.append(x)
>result.append(getImages(x[0]))
>else:
>result.append(x)
>result.append(getImages(x[0]))
>treeTraversal(getWorks(x[0]), result)
>return result
>
> My problem is that this returns the tuples to me in a flat list.
> I've been trying to work out how I can get it to return some sort of nested
> structure: nested lists, dictionaries, or html thus:
>
>
> 1,0,data
>
>555, 1, image
>556, 1, data
>
>557, 556, image
>561, 556, image
>562, 556, image
>558, 556, data
>
>559, 558, image
>560, 558, image
>
>
>563, 1, data
>
>564, 563, data
>
>565, 1, data
>
>
>
> ___
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>
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Re: [Tutor] sockets, servers, clients, broadcasts...?
Thanks for the suggestions, everyone. For now, more as a way to introduce myself to all this, I am going to have my program automatically start a server and pop up that server's ip. Then, if you want, you can type in an ip and connect to the server at that ip (ports are hard-coded at ). That way everyone is a server and a client, and either you connect to someone else as a client or they connect to you as a client. It appears, though, that I need a loop to have a server make any sense at all, to handle incoming data and connection requests. Obviously, starting this loop will then put the rest of my program on hold. Am I safe to use basic threading to stick the server's loop into a new thread? That is, will the rest of my program be able to talk to the server / will the server be able to talk to my program from its new home in its separate thread, and might I run into strange problems because of process scheduling and blocking (or not blocking)? On 6/4/10, spir wrote: > On Thu, 3 Jun 2010 18:03:34 -0400 > Alex Hall wrote: > >> Hi all, >> I am a CS major, so I have had the required networking class. I get >> the principles of networking, sockets, and packets, but I have never >> had to actually implement any such principles in any program. Now I >> have this Battleship game (not a school assignment, just a summer >> project) that I am trying to make playable over the internet, since I >> have not written the AI and playing Battleship against oneself is >> rather boring. >> >> Right now I am just trying to figure out how to implement something >> like the following: >> *you start the program and select "online game" >> *you select "server" or "client" (say you choose "server") >> *somehow, your instance of the program starts up a server that >> broadcasts something; your enemy has selected "client", and is now >> (SOMEHOW) listening for the signal your server is broadcasting >> *the signal is picked up, and, SOMEHOW, you and your opponent connect >> and can start sending and receiving data. >> >> First, how does the client know where to look for the server? I am not >> above popping up the server's ip and making the client type it in, but >> a better solution would be great. >> How do I make it so that the client can find the server correctly? The >> above IP is one thing, but are ports important here? Not a big deal if >> they are, but I am not sure. Does someone have an example of this >> process? > > I'm far to be a specialist in this field, so this is just reasoning by > watching your requirements. > > First, such a game seems to match peer-to-peer relation. This would be > different if you implemented complicated game logic, like in the case of an > AI playing. > For peers to connect, a general solution is them to register on a dedicated > public interface (the same can be used to publish a server's IP, indeed). > Then, your app first reads data there to know which (address,port) pair(s) > are available. > But since you seem to be still exploring data exchange issues, you'd better > concentrate on this basic mechanism first, choose and try one of numerous > possible solutions, then only address higher-level problems. In the > meanwhile, just put IPs and ports in a config file or even hardcode them as > constants. > > About client-server, as said above, this model does not really seem to match > your use case, I guess. But this is still an interesting alternative. I > would set my own post as server and players as clients. So, when playing > myself, I would be a local client. This indeed allows two other guys playing > using your post as server (and you maybe watching the game ;-). > But this does not make much sense if the server does not have any relevant > info to deliver (eg playing hints). > > > Denis > > > vit esse estrany ☣ > > spir.wikidot.com > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > http://mail.python.org/mailman/listinfo/tutor > -- Have a great day, Alex (msg sent from GMail website) mehg...@gmail.com; http://www.facebook.com/mehgcap ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misc question about scoping
> > flag = True if (someValue or another) else False > > > I'd prefer the form: > >flag = not not (someValue or another) Eek! no I'd just cast to a bool: flag = bool(someValue or another) but the if/else form has the Pythonic virtue of explicitness. Alan G. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misc question about scoping
On 4 jun 2010, at 21:02, ALAN GAULD wrote: Eek! no I'd just cast to a bool: flag = bool(someValue or another) but the if/else form has the Pythonic virtue of explicitness. Are you arguing that the if/else form is better than simply casting to bool because it is more explicit? You could hardly name the cast implicit, it's right there in your face. If anything, I'd say the if/else is a more indirect way of expressing te cast, even more so when you realize bool is called on the expression anyway by the if statement, to determine its truthiness. Hugo ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] sockets, servers, clients, broadcasts...?
"Alex Hall" wrote connect to you as a client. It appears, though, that I need a loop to have a server make any sense at all, to handle incoming data and connection requests. You need to listen then process incoming messages then listen some more, so yes you will need a loop. Probaqbly an infinite one: while True: listen() if someQuitMessage: break process() rest of my program on hold. Am I safe to use basic threading to stick the server's loop into a new thread? For your game you don't need to do that. A single thread should suffice. But usually a server's listen loop is the main thread and the processing goes into the sub threads. program be able to talk to the server / will the server be able to talk to my program from its new home in its separate thread, Look at the example in my tutorial. It doesn't use threads but services two separate clients without lockup. (Albeit it doesn't care about context...) -- Alan Gauld Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misc question about scoping
> Are you arguing that the if/else form is better than simply casting > to bool because it is more explicit? No, I'm simply offering a reason to use if/else in the general sense. In practice, for this specific case, I'd go with the bool(expr) form. Alan Gauld Author of the Learn To Program website http://www.alan-g.me.uk/___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misc question about scoping
On Fri, Jun 4, 2010 at 10:02 PM, ALAN GAULD wrote: > > No, I'm simply offering a reason to use if/else in the general sense. > > In practice, for this specific case, I'd go with the bool(expr) form. > Ah, then it seems we are in agreement. Sorry for the misunderstanding ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misc question about scoping
Hugo Arts wrote: On Fri, Jun 4, 2010 at 1:23 PM, Dave Angel wrote: I'd prefer the form: flag =ot not (someValue or another) That's a construct you might commonly find in languages like C, but I don't think it's very pythonic. If you want to convert your result to a bool, be explicit about it: flag =ool(some_value or another) I'd agree that the if/else construct is redundant if you just want a True/False result, but the double not is a kind of implicit type conversion that is easily avoided. Hugo I'd certainly agree that bool() is better than not not. And I admit a C background. DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misc question about scoping
On Fri, Jun 4, 2010 at 6:26 PM, Tino Dai wrote: > > LOL, it's actually on the list of things to do. And hear that one will become > a > better programmer once they learn LISP. > I most certainly did. There are very few languages as conceptually pure as this one. If you ever get it on the top of your list, check out these links. [1] is the venerable book "structure and interpretation of computer programs," commonly regarded as one of the best introductory programming books ever written. It teaches scheme. [2] is a set of excellent lectures of said book, by its writers. They are very good teachers. [1] http://mitpress.mit.edu/sicp/ [2] http://groups.csail.mit.edu/mac/classes/6.001/abelson-sussman-lectures/ > > I am always fighting the battle - more compact vs more readable :) . A couple > of > questions that I have: Why generators over map? Is it somehow more efficient > under the covers or is it for readability purposes? I noticed that you > took out the > lambda function too (not much good without a map/filter/reduce) to replace > with the generator function. Also could you give me some instances > where a generator > would be used in a real situation? I have already read the stuff on > doc.python.org about > generators. > generator expressions have essentially the same performance, but are less memory hungry, since the results do not have to be kept into memory. There is a function called imap in the itertools module that has that same benefit though, so it's not inherent to map at all. Think of the list comprehension as a more readable/concise alternative to map and filter, while generator expressions correspond to the imap/ifilter functions. Readability is the key issue here. The generator expression doesn't need a function, so the use of the lambda keyword is avoided, making it a lot shorter and easier on the eyes. It also reads more naturally. generator expressions are basically just a shortcut to generators though, which are even more powerful. Take, for example, a simple generator that yields the fibonacci sequence: def fib(): a = b = 1 while True: yield a a, b = b, a + b >>> fib() >>> it = fib() >>> for i in range(10): print it.next(), 1 1 2 3 5 8 13 21 34 55 >>> It's both more efficient and clearer than a function that simply calculates a list and returns the results. Plus it can actually go on infinitely, and you just take as many results from it as you need (also look at itertools for that, particularly takewhile). In practice it's used mostly for writing __iter__ methods, which is vastly simpler than a separate iterator class with the next method and everything. Just write __iter__ as a generator that yields your sequence, and you're done. Hugo ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misc question about scoping
On Fri, 4 Jun 2010 12:26:20 -0400 Tino Dai wrote: > Also could you give me some instances > where a generator > would be used in a real situation? I have already read the stuff on > doc.python.org about > generators. Sure, generally speaking in the programming world, documentation misses the first and principle step: *purpose* :-) Why is that stuff intended for? My point of view is as follows (I don't mean it's _the_ answer): Generators are useful when not all potential values need be generated (or possibly not all). Meaning you perform some task until a condition is met, so you don't need all possible map values. A mapping or list comprehension instead always creates them all. A particuliar case where a generator is necessary is the one of an "open", unlimited, series, defined by eg a formula, such as cubes. Such a potentially infinite series is only broken by a loop break: def cubes(first): n = first while True: yield n ** 3 n += 1 for cube in cubes(1): if cube > 999: break else: print(cube), Denis vit esse estrany ☣ spir.wikidot.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] treeTraversal, nested return?
On Fri, 4 Jun 2010 10:15:26 -0700 (PDT) jjcr...@uw.edu wrote: > All, > > any observations might be helpful. For the display of database contents I > have the following problem: > > Database querys will return data to me in tuples of the following sort: > each tuple has a unique id, a parent id, and a type. > > a parent id of 0 indicates that the element has no parent. > not all data elements have children > image elements have no children and must have a parent > > So the contents of the db is a tree of sorts: > > (1, 0, work) > (555, 1, image) > (556, 1, work) > (557, 556, image) > (558, 556, work) > (559, 558, image) > (560, 558, work) > (561, 556, image) > (562, 556, image) > (563, 1, work) > (564, 563, work) > (565, 1, work) > > I have a function that will traverse this tree, summoning lists of tuples > at each leaf. Well and good; it took a lot of trial and error, but it was > a fine education in tree traversal. > > def makeHeirarchy(id): > id = parentPath(id)[-1] > rootimages = getImages(id[0]) > rootworks = getWorks(id[0]) > heirarchy = treeTraversal(rootworks, [id, rootimages]) > return heirarchy > > ## which calls this recursive function: > > def treeTraversal(listIn,result): > for x in listIn: > if not getWorks(x[0]): > result.append(x) > result.append(getImages(x[0])) > else: > result.append(x) > result.append(getImages(x[0])) > treeTraversal(getWorks(x[0]), result) > return result > > My problem is that this returns the tuples to me in a flat list. > I've been trying to work out how I can get it to return some sort of > nested structure: nested lists, dictionaries, or html thus: For an indented output, you're simply forgetting to inform the recursive function aobut current indent level. Example (note: a nested sequence is not a tree: it has no root): SPACE , WIDTH, NODE, NL = " " , 4 , "" , '\n' def indentOutput(s, level=0): # fake root if level == 0: text = NODE else: text = "" # children level += 1 offset = level * SPACE * WIDTH for element in s: if isinstance(element, (tuple,list)): text += "%s%s%s%s" %(NL,offset,NODE , indentOutput(element, level)) else: text += "%s%s%s" %(NL,offset,element) return text s = (1,(2,3),4,(5,(6,7),8),9) print indentOutput(s) 1 2 3 4 5 6 7 8 9 Denis vit esse estrany ☣ spir.wikidot.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] sockets, servers, clients, broadcasts...?
On 6/4/10, Alan Gauld wrote:
>
> "Alex Hall" wrote
>
>> connect to you as a client. It appears, though, that I need a loop
>> to
>> have a server make any sense at all, to handle incoming data and
>> connection requests.
>
> You need to listen then process incoming messages then listen some
> more, so yes you will need a loop. Probaqbly an infinite one:
>
> while True:
> listen()
> if someQuitMessage:
> break
> process()
>> rest of my program on hold. Am I safe to use basic threading to
>> stick
>> the server's loop into a new thread?
>
> For your game you don't need to do that. A single thread should
> suffice.
The idea is to have every instance of the game start up a server (if
it is configured to do so by the user). So when a client connects to
you, you and the client exchange data (ship positions, board size, and
so on), then each move by you sends results to the client and each
move by the client sends results to you. For example, the client fires
at square A1. As soon as that happens, a toople something like
("shell","a1")
is sent to you, the server. You then see if that was a hit or a miss
on one of your ships and inform the user accordingly. Currently, the
game is based on an accelerator table inside a wx Frame, but I think
what I will do is put the calls to server.send() as required in each
function called by the accelerator table. I am not sure how I would
insert this into the server's loop; as it stands, it seems much more
intuitive to have the server spinning its wheels, waiting for things
to happen. Again, I am very new to all this, so maybe there is a
better way, but I do not know how I would put all the game logic into
a huge while loop. Oh, I am using the "toomi" library, which provides
basic client and server classes and seems to do what I need, at least
for now.
> But usually a server's listen loop is the main thread and the
> processing
> goes into the sub threads.
>
>> program be able to talk to the server / will the server be able to
>> talk to my program from its new home in its separate thread,
>
> Look at the example in my tutorial. It doesn't use threads but
> services two separate clients without lockup. (Albeit it doesn't
> care about context...)
What is the link for the tutorial? Also, maybe a bit off topic, what
is a context? I dealt with them a lot in Android programming last
semester, but I still do not get them, and I thought they were just an
Android/Java thing.
>
> --
> Alan Gauld
> Author of the Learn to Program web site
> http://www.alan-g.me.uk/
>
>
> ___
> Tutor maillist - Tutor@python.org
> To unsubscribe or change subscription options:
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>
--
Have a great day,
Alex (msg sent from GMail website)
mehg...@gmail.com; http://www.facebook.com/mehgcap
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Re: [Tutor] From SQL Blobs to Python Buffers to Actual Files
On Sat, 5 Jun 2010 03:51:02 am GoodPotatoes wrote:
> When I write the blob/binary data to a file and give it its original
> file name "customer1.rtf", I am expecting the application to read the
> binary data into text,excel,word documents, or whatever application
> created the file originally.
>
> Example:
> when I write blob1 to customer1.rtf, I get
> "xÚµVKsÛ6î93ù{ÈÁîÈ2%Û±cŸlgœdÒ<&vLJ²\J¨" as my first line.
Does that look like Rich Text Format to you? RTF looks like:
{\rtf1\ansi{\fonttbl\f0\fswiss Helvetica;}\f0\pard
This is some {\b bold} text.\par}
It's a database blob. Writing it to a file called "customer1.rtf" won't
magically turn it into RTF any more than writing it to a file
called "puppy.jpg" will magically turn it into a picture of a puppy.
Blobs are database-specific binary data, not RTF. The database could be
doing *anything* to it -- it could be compressing it, or encoding it in
some way, who knows? You have to convert the data back into RTF before
writing it. This almost certainly isn't a Python problem, but a
database problem. Consult your database documentation, and good luck.
--
Steven D'Aprano
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Re: [Tutor] sockets, servers, clients, broadcasts...?
> Look at the example in my tutorial. It doesn't use threads but What is the link for the tutorial? In my sig. Go to the V2 version and look for the Network Programming topic. > what is a context? I dealt with them a lot in Android programming Nothing to do with Android contexts I'm simply using the English meaning. In other words my example processes each request independent of the client, there is no concept of session state. It basically servers up a sequience of numbers on a firs come first served basis, it doesn't remember the last number served per client and give the next number it just serves the next number to whoever asks for one. In your case you only have one client per server - albeit with two servers - so each server only has to deal with a single client's request so again no need to keep session state (the context), you just look at the model and act accordingly. HTH, Alan G http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Misc question about scoping
"Hugo Arts" wrote [1] http://mitpress.mit.edu/sicp/ [2] http://groups.csail.mit.edu/mac/classes/6.001/abelson-sussman-lectures/ And I'd add the superb How to Design Programs: http://www.htdp.org/ It teaches Scheme programming using a recipe approach that creates a standard stricture for a function. It then extends that structure as the examples build in complexity but always keeping the basic theme. This book and SICP are two of the best for making you rethink all you thought you knew about program structure and design! If you really want to bend your brain in Lisp (Scheme) try The Little Schemer and its follow up the Seasoned Schemer It took me 3 attempts to really get to grips with the first and I'm on my second attempt at the second! What all these books will do is give you a rational approach to problem solving for programming that will often work when more 'conventional' approaches don't. The performance of the resulting code may not be optimal but it will often give you the key breakthrough that you can then rewrite more conventionally into good and fast code. It also often leads to much more elegant solutions. Good for when you have something that works but looks a mess... rethink it for Lisp and see what's different. -- Alan Gauld Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] treeTraversal, nested return?
Matthew,
sorry for responding to you instead of the list
Thanks for trying to tutor the dunderheaded. It is exactly the general
solution I wish to learn. But how, in the context of my treeTraversal
function, does one "keep track of the depth you're at"? Tabs are all very
well, but what I want is truly a nested structure, and as you point out in
that's not what I was showing in my html (though deprecated,
browsers still render lists like the one I showed).
The simplest and most graphic example would be a nested list of lists, but
for the life of me I can't work out how to generate that in this context.
Jon
On Fri, 4 Jun 2010, Matthew Wood wrote:
In general, there's 2 solutions to your "unflattening" problem.
A) The general solution: Keep track of the depth you're at, and add
tabs/spaces ('\t' * depth) as necessary.
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[Tutor] Lisphon
On Fri, 4 Jun 2010 22:33:19 +0200 Hugo Arts wrote: > On Fri, Jun 4, 2010 at 6:26 PM, Tino Dai wrote: > > > > LOL, it's actually on the list of things to do. And hear that one will > > become a > > better programmer once they learn LISP. > > > > I most certainly did. There are very few languages as conceptually > pure as this one. If you ever get it on the top of your list, check > out these links. [1] is the venerable book "structure and > interpretation of computer programs," commonly regarded as one of the > best introductory programming books ever written. It teaches scheme. > [2] is a set of excellent lectures of said book, by its writers. They > are very good teachers. > > [1] http://mitpress.mit.edu/sicp/ > [2] http://groups.csail.mit.edu/mac/classes/6.001/abelson-sussman-lectures/ Thanks for the pointer, Hugo, did not know these lectures. If you do not know lisperati, you *must* follow the pointer, if only for the home page: http://lisperati.com/. Also, history of Lisp: http://www-formal.stanford.edu/jmc/history/lisp/lisp.html Denis vit esse estrany ☣ spir.wikidot.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
