Re: [Tutor] eazy python question involving functions and parameters
>> Just think: 4 players left means that this is the semi final. > > What a brilliant answer! It tells him how to do it if he just stops and > thinks but gives nothing away. I love it. :-) i agree with alan on this. in fact, i can just picture the brackets in my head already. :-) another thing from the OP that no one has addressed yet is what *this* means: > > Write an expression (not a statement!) to the veterans, we don't have to think twice, but this may not be obvious to a beginner. basically, an expression is something like 4 * 5, foo(), [x for x in range(5)], etc. that evaluates to *some* Python object, like a number, instance, or a list, etc. this also includes function (calls) because it is associated with the single return value that comes back from every call. in contrast, a statement is something that has no intrinsic value (nor associated Python object), such as print, pass, continue, or any keywords like those. hope this helps too! -- wesley - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - "Core Python Programming", Prentice Hall, (c)2007,2001 "Python Fundamentals", Prentice Hall, (c)2009 http://corepython.com wesley.j.chun :: wescpy-at-gmail.com python training and technical consulting cyberweb.consulting : silicon valley, ca http://cyberwebconsulting.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] real world decorators
John wrote: Hi, I think I understand what decorators are and how they work. Maybe it's just me but I don't know where I'd use them in my real world programming. I see how they work with profile or coverage but does anyone have real world uses. @classmethod, @staticmethod, @property, @abstractclass, @abstractproperty are in my opinion the most import. Some toolkits use them too. I mostly create wxPython apps and don't see where they might apply. The wx toolkit is designed to work with C++ and wxPython is just a language binding for it. As far as I know C++ doesn't support Decorators or something similar like it. So there won't be many uses for decorators in wx apps. I know the tutors will enlighten me! Some ideas for decorators, if you want to play around with them: @fireandforget Make a function call in another thread, so you can return immediately - without returning result. This could be for example useful to send an email without needing to wait, until it is sent. @cache Cache the results of a function in a dictionary. If the function is called look up the value of the cache first. This only works with side-effect free functions of course. @timeout Check if the execution time of a function exceeds a timeout limit. If so raise an exception. @ignoreexceptions In my opinion, you should avoid using decorators in productive code, if you don't have a good reason to do otherwise. Every decorator adds some sort of "magic" to your program and using too much "magic" will make it difficult to maintain. - Patrick ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] eazy python question involving functions and parameters
-Original Message- >From: wesley chun >Sent: Sep 21, 2009 4:49 AM >To: tutor@python.org >Subject: Re: [Tutor] eazy python question involving functions and parameters > >>> Just think: 4 players left means that this is the semi final. >> >> What a brilliant answer! It tells him how to do it if he just stops and >> thinks but gives nothing away. I love it. :-) > >i agree with alan on this. in fact, i can just picture the brackets in >my head already. :-) Couldn't this be a king of the hill type of competition with winner of first contest takes on a remaining challenger and the winner of that takes on the last challenger? . ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] real world decorators
On Sunday 20 September 2009 03:43:32 pm Eike Welk wrote: > On Sunday 20 September 2009, John wrote: > > Hi, > > > > I think I understand what decorators are and how they work. Maybe > > it's just me but I don't know where I'd use them in my real world > > programming. I see how they work with profile or coverage but does > > anyone have real world uses. > > Frequently used are @classmethod and @staticmethod: > http://docs.python.org/library/functions.html#classmethod > > An other interesting usage of decorators is Phillip J. > Eby's 'simplegeneric' library, where decorated functions replace big > if... elif... constructions: > http://cheeseshop.python.org/pypi/simplegeneric/0.6 > > But really decorators are just syntactical sugar. They are an elegant > way to write a special case of a function call. > > Kind regards, > Eike. Thanks to all that responded on list and off. You guys have provided much to read. Thanks Johnf ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] eazy python question involving functions and parameters
another thing from the OP that no one has addressed yet is what *this* means: >/ > Write an expression (not a statement!) / to the veterans, we don't have to think twice, but this may not be obvious to a beginner. basically, an expression is something like 4 * 5, foo(), [x for x in range(5)], etc. that evaluates to *some* Python object, like a number, instance, or a list, etc. this also includes function (calls) because it is associated with the single return value that comes back from every call. in contrast, a statement is something that has no intrinsic value (nor associated Python object), such as print, pass, continue, or any keywords like those. hope this helps too! -- wesley Umm.you just completely confused me. What does it do? <>___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] eazy python question involving functions and parameters
>> an expression is something ... that evaluates to *some* Python object >>: >> in contrast, a statement is something that has no intrinsic value > > Umm.you just completely confused me. What does it do? ok, now *i*'m the one confused... what does *what* do? both expressions and statements represent executable Python code, however, a snippet of code like "4*5" has a value... it evaluates to 20, which you can optionally save or (re)use. similarly, a function, like this one that does nothing: "def foo(): pass", also has a return value (None) that you can save. however, calls to print (in Python 2), pass, if, while, for, try, etc., do NOT have any return value, because they are statements, not expressions. in fact, if you try to save a value when executing those commands, you get an error: In [1]: x = print 'hi' - File "", line 1 x = print 'hi' ^ SyntaxError: invalid syntax In [2]: of course, since print is a function in Python 3, it changes from being a statement (in Python 2) to an expression (in Python 3). again, the easiest way to differentiate b/w the 2 is whether or not it results in some Python object. if it doesn, it's an expression; if not, it's a statement. clear as mud? hope this somewhat helps... -- wesley - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - "Core Python Programming", Prentice Hall, (c)2007,2001 "Python Fundamentals", Prentice Hall, (c)2009 http://corepython.com wesley.j.chun :: wescpy-at-gmail.com python training and technical consulting cyberweb.consulting : silicon valley, ca http://cyberwebconsulting.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] eazy python question involving functions and parameters
And to remove all doubt wesley chun wrote: again, the easiest way to differentiate b/w the 2 is whether or not it results in some Python object. if it doesn, it's an expression; if not, it's a statement. Should say ... if it does, it's an expression You'll find my explanation of expressions in the Functional Programming topic in the advanced section of my tutor. 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
[Tutor] need to hire a tutor for online, i can pay by week or per hr $$$
hi i need a tutor for help with python. I'll ask you basic questions through email and such. I can pay by the hour or by week or whatever. reply here or to bmxx5...@aol.com -- View this message in context: http://www.nabble.com/need-to-hire-a-tutor-for-online%2C-i-can-pay-by-week-or-per-hr-%24%24%24-tp25530473p25530473.html Sent from the Python - tutor mailing list archive at Nabble.com. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] NameError
I keep getting the following error and don't uderstand why:
Traceback (most recent call last):
File "/home/kreglet/bin/test.py", line 15, in btnStatclick
btnStat.set_label("Pressed")
NameError: global name 'btnStat' is not defined
#!/usr/bin/env python
import gtk
import sys
class NewAppWindow(gtk.Window):
def btnStatclick(self, widget, data=None):
#print status
if self.status == True:
btnStat.set_label("Not Pressed")
self.status =False
print self.status
elif self.status == False:
btnStat.set_label("Pressed")
self.status =True
print self.status
def endapp(widget, data=None):
sys.exit()
def __init__(self):
super(NewAppWindow, self).__init__()
self.set_title("New App")
self.set_size_request(1024, 768)
self.set_keep_above(True)
self.set_position(gtk.WIN_POS_CENTER)
self.set_modal(True)
self.status=False
fixed = gtk.Layout()
btnClose = gtk.Button()
btnClose.set_use_stock(True)
btnClose.set_label("gtk-close")
btnClose.show()
btnStat = gtk.Button("Status")
fixed.put(btnStat, 650, 10)
btnStat.connect("clicked", self.btnStatclick)
fixed.put(btnClose, 650, 50)
btnClose.connect("clicked", self.endapp)
self.add(fixed)
self.connect("destroy", gtk.main_quit)
self.show_all()
NewAppWindow()
gtk.main()
--
View this message in context:
http://www.nabble.com/NameError-tp25530479p25530479.html
Sent from the Python - tutor mailing list archive at Nabble.com.
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Re: [Tutor] need to hire a tutor for online, i can pay by week or per hr $$$
On Mon, Sep 21, 2009 at 4:40 PM, daggerdvm wrote: > > hi i need a tutor for help with python. I'll ask you basic questions through > email and such. I can pay by the hour or by week or whatever. We do that for free here, just post your questions to the list. We try not to give answers to homework problems, other than that ask away! Kent ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] NameError
On Mon, Sep 21, 2009 at 4:00 PM, kreglet wrote:
>
> I keep getting the following error and don't uderstand why:
>
> Traceback (most recent call last):
> File "/home/kreglet/bin/test.py", line 15, in btnStatclick
>btnStat.set_label("Pressed")
> NameError: global name 'btnStat' is not defined
>
>
> #!/usr/bin/env python
>
> import gtk
> import sys
>
> class NewAppWindow(gtk.Window):
>
>def btnStatclick(self, widget, data=None):
>#print status
>if self.status == True:
>btnStat.set_label("Not Pressed")
>self.status =False
>print self.status
>elif self.status == False:
>btnStat.set_label("Pressed")
>self.status =True
>print self.status
btnStat isn't defined here. I think you should be declaring a self.btnStat
in the __init__ method (which I usually put as the first function in my
class - I'm honestly not sure if it makes a difference), and calling
self.btnStat
Unlike C/C++, python is explicit when dealing with members of the class. I'm
not sure if anything is implied when it comes to namespaces, but I'm pretty
sure it's all gotta be specific.
HTH,
Wayne
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Re: [Tutor] NameError
On Mon, Sep 21, 2009 at 2:06 PM, Wayne wrote:
> On Mon, Sep 21, 2009 at 4:00 PM, kreglet wrote:
>>
>> I keep getting the following error and don't uderstand why:
>>
>> Traceback (most recent call last):
>> File "/home/kreglet/bin/test.py", line 15, in btnStatclick
>> btnStat.set_label("Pressed")
>> NameError: global name 'btnStat' is not defined
>>
>>
>> #!/usr/bin/env python
>>
>> import gtk
>> import sys
>>
>> class NewAppWindow(gtk.Window):
>>
>> def btnStatclick(self, widget, data=None):
>> #print status
>> if self.status == True:
>> btnStat.set_label("Not Pressed")
>> self.status =False
>> print self.status
>> elif self.status == False:
>> btnStat.set_label("Pressed")
>> self.status =True
>> print self.status
>
> btnStat isn't defined here. I think you should be declaring a self.btnStat
> in the __init__ method (which I usually put as the first function in my
> class - I'm honestly not sure if it makes a difference), and calling
> self.btnStat
pretty much what wayne suggested. you need to put the btnStat variable
into your instance's namespace, hence self.btnStat = ... instead of
just btnStat whose namemapping will disappear when __init__()
completes even though the object still exists -- it's just an extra
reference held somewhere else.
by stashing it away into the instance('s dictionary), you'll be able
to access it again in the btnStatclick() callback.
best wishes,
-- wesley
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
"Core Python Programming", Prentice Hall, (c)2007,2001
"Python Fundamentals", Prentice Hall, (c)2009
http://corepython.com
wesley.j.chun :: wescpy-at-gmail.com
python training and technical consulting
cyberweb.consulting : silicon valley, ca
http://cyberwebconsulting.com
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Re: [Tutor] How to get homework help (was need to hire a tutor... )
On Mon, 2009-09-21 at 17:04 -0400, Kent Johnson wrote: > On Mon, Sep 21, 2009 at 4:40 PM, daggerdvm wrote: > > > > hi i need a tutor for help with python. I'll ask you basic questions > > through > > email and such. I can pay by the hour or by week or whatever. > > We do that for free here, just post your questions to the list. We try > not to give answers to homework problems, other than that ask away! > > Kent I'm new on this list <*waves hello to everyone*>, but I suspect the trick to getting help here with homework is pretty much the same as most other tech lists. 1. Flag the problem as homework. Don't try and deceive those who are trying to help. 2. Outline your understanding of the problem; Both what you do understand, and what you don't. 3. Post the code you've tried. For larger code blocks, try and explain what you're wanting each section of the code to do. This is probably more for your benefit (to help clarify your thinking on the problem) than for the experts here; They'll have a pretty good handle on what the code really is doing ;-) 4. If you haven't got code yet, post pseudo code outlining how you might approach the problem. This will help develop your algorithm for solving the problem. Don't underestimate the importance of this step. If you don't have a good algorithm for solving the problem, all the language syntax in the world won't help. 5. Accept that you won't be given answers directly, but there is an enormous amount of patience, help and sympathy for those first starting out. Everyone who has reached the 'high ground' on the learning journey likes to see someone new starting out and making headway on the same journey. They'll (almost always) gladly extend a hand in help, but won't do the journey for you. Anything worthwhile must be earned, and that means putting in the hard yards. Be polite, patient and respectful of those who have gone before you, and they'll keep extending the hand of help. Abuse the help, and it won't last long. A bit like life in general really. 6. Don't post the same question in every forum you can find. Any decent forum will have enough experts to help out. And don't abuse those contributing to the discussion; remember that bit about showing respect? And that help being withdrawn? 7. The advice given on http://www.pubbs.net/python/200909/108644/ shouldn't be ignored (yes, I can use google too). ESR (love him or loath him) really was giving good advice in http://catb.org/~esr/faqs/smart-questions.html. There is a reason it gets quoted regularly. Ignore it at your peril. Try it on the problem you posted previously; you might not have understood the hints that were given (probably not if your postings elsewhere are anything to go by) but if you're fair dinkum give it a go. If your just wanting to pass your class by getting others to solve your programming problems for you, get some spine and do it properly or fail graciously. The alternative is to be a fraud, and that never gets respect. Tim Bowden ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] ex-ftp
hello friends
I am trying to write a class to save a url.page.
But it is not working.It is saving the html.page.But not getting
images.I am unable to show the list (object.links).
Please take a look at it and show me how to rectify it.
import urllib2,ftplib,re
class Collect:
def __init__(self,parent):
self.parent=parent
self.links=[]
self.ims=[]
s=urllib2.urlopen(self.parent)
data=s.read()
self.data=data
a=re.compile ('<[aA].*[\'"](.*)[\'"].*>'); b=re.compile('http://www.asstr.org')
c.save(c.data)
c.bring()
#c.show(c.ims)
c.links
Thanks in advance.
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Re: [Tutor] ex-ftp
On Tue, Sep 22, 2009 at 2:39 PM, prasad rao wrote:
> hello friends
> I am trying to write a class to save a url.page.
> But it is not working.It is saving the html.page.But not getting
> images.I am unable to show the list (object.links).
> Please take a look at it and show me how to rectify it.
>
> import urllib2,ftplib,re
> class Collect:
> def __init__(self,parent):
> self.parent=parent
> self.links=[]
> self.ims=[]
> s=urllib2.urlopen(self.parent)
> data=s.read()
> self.data=data
> a=re.compile ('<[aA].*[\'"](.*)[\'"].*>'); b=re.compile(' img[\'"](.+)[\'"].*')
> try:
> z=re.search(a,self.data).group(1)
> self.links.extend(z)
> except:pass
> try:
> y=re.search(b,self.data).group(1)
> self.ims.extend(y)
> except:pass
> return
>
> def save(self,data):
> d=open('C:/%s .html'%self.parent[10:15],'w')
> d.write(data)
> return
> def bring(self):
> ftp=ftplib.FTP(self.parent)
> ftp.login()
> for x in self.ims:
> data=ftp.retlines(x)
> d=open('C:/%s'%x,'w')
> d.write(data)
> return
>
> def show(self,z):
> for x in z:
> print x
> return
>
>
> c=Collect('http://www.asstr.org')
> c.save(c.data)
> c.bring()
> #c.show(c.ims)
> c.links
>
> Thanks in advance.
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>
>
Might be nice to mention to all who access these emails from work that
the site this script is scraping is not safe for work.
-Mal
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