[Tutor] conventions for establishing and saving default values for variables
Hi I was wondering if anyone could give me some insight as to the best way to get and save variables from a user the first time a script is opened. For example if the script prompts something like "What is the path to the folder?" and the result is held in a variable called thePath, what is the best way to have that variable saved for all subsequent uses of the script by the same user. Pete ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] How to numerically sort strings that start with numbers?
theList = ["21 trewuuioi","3zxc","134445"] print sorted(theList) Hi, the result of the sorted list above doesn't print in the order I want. Is there a straight forward way of getting python to print ['3zxc','21 trewuuioi','134445'] rather than ['134445', '21 trewuuioi', '3zxc']? Any help would be greatly appreciated Pete ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] find and replace relative to an nearby search string in a file
Hi, I am trying to do a find and replace in a text file (a nuke script).
Here are a couple excerpts from the file that demonstrate what I want to do.
I am always looking for the line " name Write1" as my starting point. In the
first example below, I want to replace the path, which is 2 lines above it.
I have made a basic script to do that and it works fine. The problem I am
having is when the number of lines between " name Write1" and the path above
it is not 1, my script breaks. I'm not sure how to say in python "when you
find the line " name Write1", go back line by line until you find a line
that begins with " file /Volumes/" and then assign a new variable to the
path on that line".
At the very bottom of this post I have included what I have so far (The
script which works but breaks). Any help would be greatly appreciated.
Pete
Write {
file /Volumes/raid0/Z353_002_comp_v27.%04d.cin
file_type cin
name Write1
xpos 13762
ypos -364
}
Write {
file /Volumes/raid0/Z353_002_comp_v04.%04d.exr
colorspace linear
raw true
file_type exr
name Write1
selected true
xpos -487
ypos -155
}
# This is the basic script
import re
theFile = open('/Volumes/raid0/Z353_001_comp_v05.nk',"r")
theNukeScriptText = theFile.read()
theFile.close()
#p = re.compile('.+_comp_v\d\d.%04d.cin\n file_type cin\n name Write1')
p = re.compile(r'.+_comp_v\d\d.%04d.cin\n.+\n name Write1')
m = p.finditer(theNukeScriptText)
the3Lines = p.findall(theNukeScriptText)
the3LinesString = ''.join(the3Lines)
theOldSeq = the3LinesString.split('\n')[0]
print str(the3LinesString.split('\n')[0])
theNewSeq = 'file /Volumes/raid0/Z353_002_comp_v27.%04d.cin'
theFile = open('/Volumes/raid0/Z353_001_comp_v05.nk', "w")
theFile.write(theNukeScriptText.replace(theOldSeq,theNewSeq))
theFile.close()
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[Tutor] open linux file browser from nuke python script
Hi, I am trying to get a python script to open up a file browser window with the location of a folder. I am using kubuntu 10.04. The string that gets created works fine if I paste it into a shell eg: 'kde-open path/to/the/sequence', but it doesn't seem to want to run from within my interpreter using either subprocess.Popen or os.system For the first argument I have tried 'kde-open', 'konqueror', and a few others that all work fine in the shell but not in my interpreter. Here is what my script looks like: import nuke import subprocess def showFolder(): subprocess.Popen(['kde-open', 'path/to/the/sequence']) showFolder() ### I must to run it from a specific interpreter (Nuke, the compositing software) Anyone have any idea what I might be doing wrong? Can anyone suggest a workaround? Pete ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] getting the last file in a folder (reliably)
Hi I have some code which works nine times out of ten. Maybe some could help
me make this a little more robust. I have a bunch of files in a folder with
a strict versioning based naming convention, where I want to open the
highest version number of a nuke script (not necessarily the one with the
newest modification date). So in the example folder contents listed below I
want to open "233_bb0072_comp_comp2k_v05.nk" (fourth from the bottom). Every
once in a while my python script ends up opening
233_bb0072_comp_comp2k_v04.nk (the next to last correct one). The script I
am using is shown below. Can anyone explain why it doesn't always work?
233_bb0072_comp_comp2k_v01.nk
233_bb0072_comp_comp2k_v01.nk~
233_bb0072_comp_comp2k_v02.nk
233_bb0072_comp_comp2k_v03.nk
233_bb0072_comp_comp2k_v03.nk~
233_bb0072_comp_comp2k_v04.nk
233_bb0072_comp_comp2k_v04.nk~
233_bb0072_comp_comp2k_v05.nk
233_bb0072_comp_comp2k_v05.autosave
233_bb0072_comp_comp2k_v05.nk~
233_bb0072_comp_comp2k_v06.nk
###
import os
def openNewestCompCommandLine():
theDirectory = "/path/to/my/comps/"
theFilesInTheFolder = os.listdir(theDirectory)
for aFile in theFilesInTheFolder:
if "~" not in aFile:
if "autosave" not in aFile:
theNukeFileName = aFile
theFullPath = theDirectory + theNukeFileName
os.system("nuke " + theFullPath)
if __name__ == '__main__':
openNewestCompCommandLine()
for aFile in theFilesInTheFolder:
print aFile
Pete
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[Tutor] how to temporarily disable a function
Hi I was wondering if there is a way to disable a function. Hi have a GUI grid snapping function that I use in a program called Nuke (the film compositing software) Here is the function (which loads when Nuke loads): ### def theAutoplaceSnap(): try: nuke.thisNode().autoplace() n = nuke.allNodes(); for i in n: nuke.autoplaceSnap(i) except: pass nuke.addOnUserCreate(theAutoplaceSnap) ### I have many functions which get loaded, but this particular one needs to be disabled when I am viewing another compositors script in the gui. I have a python script editor in Nuke in which I can run code if need be to run code on the fly. Help -- Pete ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] return, why do I need it?
Hi I have been writing python code for a while now and I never return anything within any of my functions, I just (eg.) print stuff or make directories or update a log or what have you. When I look at other people's code they are always returning in their functions and I was wondering if someone could give me an example of when I would absolutely have to return something. The thing I don't like about returning is that when I unindent a function and try to run the code to inspect parts of it for debugging I always have to alter the code so as not to get the "return not inside a function error", so I will change the word "return" to "print" and in many cases that's the way I leave it. Anyone have any thoughts on this? Thanks Pete ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] commands.getoutput equivalent in subprocess
Hello I print a lot of values at work using grep and need to be
constantly opening a shell window to do this (rather than staying
within my main program which is Nuke by the Foundry). Is there a
simple equilavent to commands.getoutput that is more up to date (I
would assume within the subprocess module)? It sounds like the
commands module will be phased out soonish. I am using Python 2.6
Here is the kind of thing I would like to do in subprocess
import commands
output = commands.getoutput("echo Hello World!")
print output
Thanks
Pete
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Re: [Tutor] commands.getoutput equivalent in subprocess
Ok thanks a lot. Pete On Mon, Mar 19, 2012 at 10:01 PM, Peter Otten <__pete...@web.de> wrote: >> Pete O'Connell wrote: > >> Hi, I am using Python 2.6 I can't use Python 3 in this particular > situation. > > [Please reply to the list, not in private mail.] > > You can continue to use commands.getoutput() in 2.6 and 2.7, and once you > are ready to make the jump to 3.x replace it with subprocess.getoutput(). > > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > http://mail.python.org/mailman/listinfo/tutor -- Pete ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] list comprehension, testing for multiple conditions
Hi I am trying to parse a text file and create a list of all the lines
that don't include: "vn", "vt" or are empty. I want to make this as
fast as possible because I will be parsing many files each containing
thousands of lines. I though I would give list comprehensions a try.
The last 3 lines of the code below have three list comprehensions that
I would like to combine into 1 but I am not sure how to do that.
Any tips would be greatly appreciated
pete
#start
fileName = '/usr/home/poconnell/Desktop/objCube.obj'
theFileOpened = open(fileName,'r')
theTextAsList = theFileOpened.readlines()
theTextAsListStripped = []
for aLine in theTextAsList:
theTextAsListStripped.append(aLine.strip("\n"))
theTextAsListNoVn = [x for x in theTextAsListStripped if "vn" not in x]
theTextAsListNoVnOrVt = [x for x in theTextAsListNoVn if "vt" not in x]
theTextAsListNoVnOrVtOrEmptyLine = [x for x in theTextAsListNoVn if x != ""]
#end
and here is the simple file I am parsing as a test:
#start##
## OBJ file generated by Nuke ##
# vertex list - offset=0
v 0.00 0.00 1.00
v 1.00 0.00 1.00
v 0.00 1.00 1.00
v 1.00 1.00 1.00
v 1.00 0.00 0.00
v 0.00 0.00 0.00
v 1.00 1.00 0.00
v 0.00 1.00 0.00
v 1.00 0.00 1.00
v 1.00 0.00 0.00
v 1.00 1.00 1.00
v 1.00 1.00 0.00
v 0.00 0.00 0.00
v 0.00 0.00 1.00
v 0.00 1.00 0.00
v 0.00 1.00 1.00
v 0.00 1.00 1.00
v 1.00 1.00 1.00
v 0.00 1.00 0.00
v 1.00 1.00 0.00
v 0.00 0.00 0.00
v 1.00 0.00 0.00
v 0.00 0.00 1.00
v 1.00 0.00 1.00
# point texture coordinates - offset=0
vt 0.00 0.00
vt 1.00 0.00
vt 0.00 1.00
vt 1.00 1.00
vt 0.00 0.00
vt 1.00 0.00
vt 0.00 1.00
vt 1.00 1.00
vt 0.00 0.00
vt 1.00 0.00
vt 0.00 1.00
vt 1.00 1.00
vt 0.00 0.00
vt 1.00 0.00
vt 0.00 1.00
vt 1.00 1.00
vt 0.00 0.00
vt 1.00 0.00
vt 0.00 1.00
vt 1.00 1.00
vt 0.00 0.00
vt 1.00 0.00
vt 0.00 1.00
vt 1.00 1.00
# vertex normals - offset=0
vn 0.00 0.00 1.00
vn 0.00 0.00 1.00
vn 0.00 0.00 1.00
vn 0.00 0.00 1.00
vn 0.00 0.00 -1.00
vn 0.00 0.00 -1.00
vn 0.00 0.00 -1.00
vn 0.00 0.00 -1.00
vn 1.00 0.00 0.00
vn 1.00 0.00 0.00
vn 1.00 0.00 0.00
vn 1.00 0.00 0.00
vn -1.00 0.00 0.00
vn -1.00 0.00 0.00
vn -1.00 0.00 0.00
vn -1.00 0.00 0.00
vn 0.00 1.00 0.00
vn 0.00 1.00 0.00
vn 0.00 1.00 0.00
vn 0.00 1.00 0.00
vn 0.00 -1.00 0.00
vn 0.00 -1.00 0.00
vn 0.00 -1.00 0.00
vn 0.00 -1.00 0.00
f 1/1/1 2/2/2 4/4/3 3/3/4
f 5/5/5 6/6/6 8/8/7 7/7/8
f 9/9/9 10/10/10 12/12/11 11/11/12
f 13/13/13 14/14/14 16/16/15 15/15/16
f 17/17/17 18/18/18 20/20/19 19/19/20
f 21/21/21 22/22/22 24/24/23 23/23/24
# end of file
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Re: [Tutor] list comprehension, testing for multiple conditions
What a great mailing list!
Thanks for all the responses.
I have a few questions, though, first in regards to Puneeth's code. He
writes to use:
>theTextAsListNoVnOrVtOrEmptyLine = [x for x in theTextAsListStripped if "vn"
>not in x and "vt" not in x and x!= ""]
It works but what I don't understand about this line is why the ands
are nor ors ("or" doesn't work even though I would have expected it
to)
I am sure I will have a few more questions over the next couple days
as I work my way through the responses.
Thanks
Pete
On Wed, Aug 22, 2012 at 6:23 PM, Puneeth Chaganti wrote:
> On Wed, Aug 22, 2012 at 11:35 AM, Pete O'Connell
> wrote:
>> Hi I am trying to parse a text file and create a list of all the lines
>> that don't include: "vn", "vt" or are empty. I want to make this as
>> fast as possible because I will be parsing many files each containing
>> thousands of lines. I though I would give list comprehensions a try.
>> The last 3 lines of the code below have three list comprehensions that
>> I would like to combine into 1 but I am not sure how to do that.
>> Any tips would be greatly appreciated
>>
>> pete
>>
>> #start
>> fileName = '/usr/home/poconnell/Desktop/objCube.obj'
>> theFileOpened = open(fileName,'r')
>> theTextAsList = theFileOpened.readlines()
>>
>> theTextAsListStripped = []
>> for aLine in theTextAsList:
>>
>> theTextAsListStripped.append(aLine.strip("\n"))
>>
>> theTextAsListNoVn = [x for x in theTextAsListStripped if "vn" not in x]
>> theTextAsListNoVnOrVt = [x for x in theTextAsListNoVn if "vt" not in x]
>> theTextAsListNoVnOrVtOrEmptyLine = [x for x in theTextAsListNoVn if x != ""]
>
> Something like this should work :
>
> theTextAsListNoVnOrVtOrEmptyLine = [x for x in theTextAsListStripped
> if "vn" not in x and "vt" not in x and x!= ""]
>
> HTH,
> Puneeth
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Re: [Tutor] list comprehension, testing for multiple conditions
Thanks Peter. This looks like what I need:
with open(fileName) as lines:
wanted = [line.strip("\n") for line in lines if "vn" not in line
and "vt" not in line and line != "\n"]
Cheers
And in response to Allan's suggestion. I can see using a generator in
a situation where the if statements were more numerous and complex. I
am sure that will come in handy.
Thanks
On Wed, Aug 22, 2012 at 7:06 PM, Peter Otten <__pete...@web.de> wrote:
> Pete O'Connell wrote:
>
>> Hi I am trying to parse a text file and create a list of all the lines
>> that don't include: "vn", "vt" or are empty. I want to make this as
>> fast as possible because I will be parsing many files each containing
>> thousands of lines. I though I would give list comprehensions a try.
>> The last 3 lines of the code below have three list comprehensions that
>> I would like to combine into 1 but I am not sure how to do that.
>> Any tips would be greatly appreciated
>>
>> pete
>>
>> #start
>> fileName = '/usr/home/poconnell/Desktop/objCube.obj'
>> theFileOpened = open(fileName,'r')
>> theTextAsList = theFileOpened.readlines()
>
> If you have a file with 1,000,000 lines you have now a list of 1,000,000
> strings of which perhaps 1,000 match your criteria. You are squandering
> memory. Rule of thumb: never use readlines(), iterate over the file
> directly.
>
>> theTextAsListStripped = []
>> for aLine in theTextAsList:
>>
>> theTextAsListStripped.append(aLine.strip("\n"))
>>
>> theTextAsListNoVn = [x for x in theTextAsListStripped if "vn" not in x]
>> theTextAsListNoVnOrVt = [x for x in theTextAsListNoVn if "vt" not in x]
>> theTextAsListNoVnOrVtOrEmptyLine = [x for x in theTextAsListNoVn if x !=
>> ""]
>
> I think that should be
>
> theTextAsListNoVnOrVtOrEmptyLine = [x for x in theTextAsListNoVnOrVt if x !=
> ""]
>
> You can combine the three if clauses or add them all to one list-comp:
>
> with open(filename) as lines:
> wanted = [line.strip("\n") for line in lines
> if "vn" not in line and "vt" not in line and line != "\n"]
>
>
> You can even have multiple if clauses in one list-comp (but that is rarely
> used):
>
> with open(filename) as lines:
> wanted = [line.strip("\n") for line
> if "vn" not in line
> if "vt" not in x
> if line != "\n"]
>
> While your problem is simple enough to combine all filters into one list-
> comp some problems are not. You can then prevent the intermediate lists from
> materializing by using generator expressions. The result minimizes memory
> consumption, too, and should be (almost) as fast. For example:
>
> with open(filename) as lines:
> # use gen-exps to remove empty and whitespace-only lines
> stripped = (line.strip() for line in lines)
> nonempty = (line for line in stripped if line)
>
> wanted = [line for line in nonempty
> if "vt" not in line and "vn" not in line]
>
>
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Re: [Tutor] list comprehension, testing for multiple conditions
Hi. The next step for me to parse the file as I want to is to change
lines that look like this:
f 21/21/21 22/22/22 24/24/23 23/23/24
into lines that look like this:
f 21 22 23 24
Below is my terribly slow loop for doing this. Any suggestions about
how to make this code more efficient would be greatly appreciated
fileName = '/usr/home/poconnell/Desktop/objCube.obj'
with open(fileName) as lines:
theGoodLines = [line.strip("\n") for line in lines if "vn" not in
line and "vt" not in line and line != "\n"]
for i in range(len(theGoodLines)):
if theGoodLines[i][0] == "f":
aGoodLineAsList = theGoodLines[i].split(" ")
theGoodLines[i] = aGoodLineAsList[0] + " " +
aGoodLineAsList[1].split("/")[-1] + " " +
aGoodLineAsList[2].split("/")[-1] + " " +
aGoodLineAsList[3].split("/")[-1] + " " +
aGoodLineAsList[4].split("/")[-1]
for anItem in theGoodLines:
print anItem
##
Thanks!
Pete
On Wed, Aug 22, 2012 at 9:59 PM, Pete O'Connell wrote:
> Thanks Peter. This looks like what I need:
>
> with open(fileName) as lines:
> wanted = [line.strip("\n") for line in lines if "vn" not in line
> and "vt" not in line and line != "\n"]
>
> Cheers
>
> And in response to Allan's suggestion. I can see using a generator in
> a situation where the if statements were more numerous and complex. I
> am sure that will come in handy.
>
> Thanks
>
>
> On Wed, Aug 22, 2012 at 7:06 PM, Peter Otten <__pete...@web.de> wrote:
>> Pete O'Connell wrote:
>>
>>> Hi I am trying to parse a text file and create a list of all the lines
>>> that don't include: "vn", "vt" or are empty. I want to make this as
>>> fast as possible because I will be parsing many files each containing
>>> thousands of lines. I though I would give list comprehensions a try.
>>> The last 3 lines of the code below have three list comprehensions that
>>> I would like to combine into 1 but I am not sure how to do that.
>>> Any tips would be greatly appreciated
>>>
>>> pete
>>>
>>> #start
>>> fileName = '/usr/home/poconnell/Desktop/objCube.obj'
>>> theFileOpened = open(fileName,'r')
>>> theTextAsList = theFileOpened.readlines()
>>
>> If you have a file with 1,000,000 lines you have now a list of 1,000,000
>> strings of which perhaps 1,000 match your criteria. You are squandering
>> memory. Rule of thumb: never use readlines(), iterate over the file
>> directly.
>>
>>> theTextAsListStripped = []
>>> for aLine in theTextAsList:
>>>
>>> theTextAsListStripped.append(aLine.strip("\n"))
>>>
>>> theTextAsListNoVn = [x for x in theTextAsListStripped if "vn" not in x]
>>> theTextAsListNoVnOrVt = [x for x in theTextAsListNoVn if "vt" not in x]
>>> theTextAsListNoVnOrVtOrEmptyLine = [x for x in theTextAsListNoVn if x !=
>>> ""]
>>
>> I think that should be
>>
>> theTextAsListNoVnOrVtOrEmptyLine = [x for x in theTextAsListNoVnOrVt if x !=
>> ""]
>>
>> You can combine the three if clauses or add them all to one list-comp:
>>
>> with open(filename) as lines:
>> wanted = [line.strip("\n") for line in lines
>> if "vn" not in line and "vt" not in line and line != "\n"]
>>
>>
>> You can even have multiple if clauses in one list-comp (but that is rarely
>> used):
>>
>> with open(filename) as lines:
>> wanted = [line.strip("\n") for line
>> if "vn" not in line
>> if "vt" not in x
>> if line != "\n"]
>>
>> While your problem is simple enough to combine all filters into one list-
>> comp some problems are not. You can then prevent the intermediate lists from
>> materializing by using generator expressions. The result minimizes memory
>> consumption, too, and should be (almost) as fast. For example:
>>
>> with open(filename) as lines:
>> # use gen-exps to remove empty and whitespace-only lines
>> stripped = (line.strip() for line in lines)
>> nonempty = (line for line in stripped if line)
>>
>> wanted = [line for line in nonempty
>> if "vt" not in line and "vn" not in line]
>>
>>
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>
>
>
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> -
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Re: [Tutor] list comprehension, testing for multiple conditions
Thanks eryksun, that is a very clear example.
Cheers
pete
On Wed, Aug 22, 2012 at 11:16 PM, eryksun wrote:
> On Wed, Aug 22, 2012 at 3:06 AM, Peter Otten <__pete...@web.de> wrote:
>>
>> wanted = [line.strip("\n") for line in lines
>> if "vn" not in line and "vt" not in line and line != "\n"]
>
> Here's an equivalent expression with the negation factored out:
>
> not ("vn" in line or "vt" in line or line == "\n")
>
> http://en.wikipedia.org/wiki/De_Morgan%27s_laws
>
> If you have a lot of tests all using the same operator (e.g. "in"),
> you can use "any" (OR) or "all" (AND) with a generator expression:
>
> vals = ["vn", "vt", "vu", "vv", "vw", "vx", "vy", "vz"]
> wanted = [line for line in lines if not any(v in line for v in vals)]
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Re: [Tutor] list comprehension, testing for multiple conditions
On Thu, Aug 23, 2012 at 2:53 AM, Steven D'Aprano wrote:
> On 22/08/12 20:28, Pete O'Connell wrote:
>>
>> Hi. The next step for me to parse the file as I want to is to change
>> lines that look like this:
>> f 21/21/21 22/22/22 24/24/23 23/23/24
>> into lines that look like this:
>> f 21 22 23 24
>
>
> In English, what is the rule you are applying here? My guess is:
>
> "Given three numbers separated by slashes, ignore the first two numbers
> and keep the third."
>
> E.g. "17/25/97" => 97.
>
> Am I close?
Hi Steve, yes that is correct
>
>
>
>> Below is my terribly slow loop for doing this. Any suggestions about
>> how to make this code more efficient would be greatly appreciated
>
>
> What makes you say it is "terribly slow"? Perhaps it is as fast as it
> could be under the circumstances. (Maybe it takes a long time because
> you have a lot of data, not because it is slow.)
OK maybe I am wrong about it being slow (I thought for loops were
slower than lis comprehensions). But I do know I need it to be as fast
as possible if I need to run it on a thousand files each with hundreds
of thousands of lines
>
> The first lesson of programming is not to be too concerned about speed
> until your program is correct.
>
> Like most such guidelines, this is not entirely true -- you don't want
> to write code which is unnecessarily slow. But the question you should
> be asking is, "is it fast enough?" rather than "is it fast?".
>
> Also, the sad truth is that Python tends to be slower than some other
> languages. (It's also faster than some other languages too.) But the
> general process is:
>
> 1) write something that works correctly;
>
> 2) if it is too slow, try to speed it up in Python;
>
> 3) if that's still too slow, try using something like cython or PyPy
>
> 4) if all else fails, now that you have a working prototype, re-write
> it again in C, Java, Lisp or Haskell.
>
> Once they see how much more work is involved in writing fast C code,
> most people decide that "fast enough" is fast enough :)
OK I will keep it as is and see if I can live with it.
Thanks
Pete
>
>
>
>> with open(fileName) as lines:
>> theGoodLines = [line.strip("\n") for line in lines if "vn" not in
>> line and "vt" not in line and line != "\n"]
>
>
> I prefer to write code in chains of filters.
>
> with open(fileName) as lines:
> # get rid of leading and trailing whitespace, including newlines
> lines = (line.strip() for line in lines)
> # ignore blanks
> lines = (line in lines if line)
> # ignore lines containing "vn" or "vt"
> theGoodLines = [line in lines if not ("vn" in line or "vt" in line)]
>
> Note that only the last step is a list comprehension using [ ], the others
> are generator expressions using ( ) instead.
>
> Will the above be faster than your version? I have no idea. But I think it
> is more readable and understandable. Some people might disagree.
>
>
>
>> for i in range(len(theGoodLines)):
>> if theGoodLines[i][0] == "f":
>> aGoodLineAsList = theGoodLines[i].split(" ")
>> theGoodLines[i] = aGoodLineAsList[0] + " " +
>> aGoodLineAsList[1].split("/")[-1] + " " +
>> aGoodLineAsList[2].split("/")[-1] + " " +
>> aGoodLineAsList[3].split("/")[-1] + " " +
>> aGoodLineAsList[4].split("/")[-1]
>
>
>
> Start with a helper function:
>
> def extract_last_item(term):
> """Extract the item from a term like a/b/c"""
> return term.split("/")[-1]
>
>
> for i, line in enumerate(theGoodLines):
> if line[0] == "f":
> terms = line.split()
> theGoodLines[i] = " ".join([extract_last_item(t) for t in terms])
>
>
>
> See how you go with that.
>
>
>
> --
> Steven
>
> ___
> Tutor maillist - Tutor@python.org
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Re: [Tutor] list comprehension, testing for multiple conditions
On Thu, Aug 23, 2012 at 4:16 AM, Alan Gauld wrote: > theTextAsListNoVnOrVtOrEmptyLine = [x for x in theTextAsListStripped > if "vn" not in x > if "vt" not in x > if x!= ""] > > It's slightly more verbose but it makes the rules more explicit, IMHO. I agree, it seems easier to read when written on multiple lines. I'll do it that way, Thanks Pete ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] list comprehension, testing for multiple conditions
Ok thanks for the advice everyone. Cheers Pete On Thu, Aug 23, 2012 at 10:58 AM, Jerry Hill wrote: > On Wed, Aug 22, 2012 at 5:23 PM, Pete O'Connell > wrote: >> OK maybe I am wrong about it being slow (I thought for loops were >> slower than lis comprehensions). But I do know I need it to be as fast >> as possible if I need to run it on a thousand files each with hundreds >> of thousands of lines > > You're quite likely wrong about that. The overall runtime of your > code is very likely to end up dominated by I/O with the hard drive, > not the microsecond differences in how you process each line. The way > to know for sure is to write code that is easy to read and does the > correct thing. Then run the code an see if it's too slow for your > purposes. If it is, profile the code and see where it's spending all > of its time. Only then can you actually optimize the right places. > > Once you've identified where your code needs to be faster, you're > likely to get more mileage out of a clever algorithm change than a > micro-optimization to your filtering. Or maybe you'll discover that it > really is worthwhile to optimize your filtering, because it's inside a > tight loop, and that's where all of your time is spent. There are a > lot of tricks you can use to slightly speed up your python code, but > none of them are worth doing until you know for sure that you're > optimizing in the right place. And if it turns out that the code's > runtime is fine as first written, you don't have to waste your time > doing lots of work for little gain. > > -- > Jerry > ___ > Tutor maillist - Tutor@python.org > To unsubscribe or change subscription options: > http://mail.python.org/mailman/listinfo/tutor -- - ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] list comprehension, testing for multiple conditions
Hi, I have tried to simplify things and am running into a bit of trouble.
What i am really trying to do is: Keep all the lines starting with "v " and
then delete those lines whose modulus 5 don't equal zero
I have written it like this which seems to take a really long time (a
couple of minutes when iteration over a folder with 200 files to parse)
#
with open(theFilePath) as lines:
#keep only the lines beginning with "v " (this works)
theGoodLines = [line.strip("\n") for line in lines if "v " ==
line[0:2]]
theLinesAsListSubset = []
for i in range(len(theGoodLines)):
nuke.tprint(i)
if i%5 != 0:
continue
elif i%5 == 0:
theLinesAsListSubset.append(theGoodLines[i])
I think it would be better to include the modulud test within the original
list comprehension but I am not sure how to access the index of "line":
#something like this is a sketch of what I mean (I know it's wrong)
theGoodLines = [line.strip("\n") for line in lines if "v " ==
line[0:2] and line.getIndex() % 5 == 0]
Do I need enumerate for this maybe?
Thanks
Pete
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[Tutor] reducing a list evenly when deleting elements by index
Hi, I have a bezier line with 20 points on it and I am trying to reduce this to a line with 4 points, keeping the first and last points and 2 evenly spaced points in between like so: ** becomes: *. . . .* These points are removable only by index, so if I remove point 2, point 3 then becomes point 2 in the next iteration, so I end up having a spacing like this which is not what I want: *. . . .* Here is the code that I have so far. I hope it makes sense: ## for aNode in nuke.allNodes(): if aNode.shown(): theRotoNode = aNode curveKnob = theRotoNode['curves'] rootLayer = curveKnob.rootLayer theNumberOfPointToReduceTo = 5 for aShape in rootLayer: theOriginalShape = aShape thePointList = [] for aPoint in aShape: thePointList.append(aPoint) if len(thePointList) > 5: theNumberOfPoints = len(thePointList) keepEvery = float(theNumberOfPoints)/theNumberOfPointToReduceTo theIndicesToKeep = [] theIndicesToKeep.append(0) theIndicesToKeep.append(1) for i in range(theNumberOfPoints)[1:-1]: if i*keepEvery < theNumberOfPoints: theIndicesToKeep.append(int(round(i*keepEvery))) theIndicesToKeep.append(theNumberOfPoints-2) theIndicesToKeep.append(theNumberOfPoints-1) thePointsToRemove = tuple(set(range(theNumberOfPoints)) - set(theIndicesToKeep)) #everything is good up to here, the code below doesn't work properly and I'm kinda stuck counter = -1 for aPointIndex in thePointsToRemove: counter+=1 aPointIndex = aPointIndex-(counter) print aPointIndex aShape.remove(aPointIndex) Any advice would be greatly appreciated. Pete ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] reducing a list evenly when deleting elements by index
Ah of course. Thanks very much Oscar! Pete On Mon, Sep 17, 2012 at 1:29 PM, Oscar Benjamin wrote: > On 17 September 2012 02:15, Pete O'Connell wrote: > >> Hi, I have a bezier line with 20 points on it and I am trying to reduce >> this to a line with 4 points, keeping the first and last points and 2 >> evenly spaced points in between like so: >> ** >> becomes: >> *. . . .* >> >> These points are removable only by index, so if I remove point 2, >> point 3 then becomes point 2 in the next iteration, so I end up having a >> spacing like this which is not what I want: >> *. . . .* > > > But removing item 19 doesn't affect the position of item 2. The trick is > to start the loop at the end of the list and work back to the beginning. > > Oscar > -- - ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] reducing a list evenly when deleting elements by index
> 1) You have a Bezier curver consisting of 20 control points and would like > to > approximate it with a simpler cubic Bezier curve consisting of only 4 > points. > I would call this "approximating a Bezier with a lower order Bezier". > > Hi Oscar. Thanks for your reply. This one above is the one that I am trying to do. It is true that choosing arbitrary points evenly selected from the original points is not ideal, it is good enough for my purposes in most cases. When I have a bit more time I am going to try to implement the Ramer–Douglas–Peucker algorithm to improve the accuracy of my curve simplification: http://en.wikipedia.org/wiki/Ramer%E2%80%93Douglas%E2%80%93Peucker_algorithm Thanks Pete ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] reducing a list evenly when deleting elements by index
Thanks Stephen. That looks like nice clean code too! Cheers Pete On Tue, Sep 18, 2012 at 9:59 AM, Stephen Haywood < step...@averagesecurityguy.info> wrote: > Someone has already tried. https://github.com/sebleier/RDP > > > On Mon, Sep 17, 2012 at 5:50 PM, Pete O'Connell > wrote: > >> When I have a bit more time I am going to try to implement the >> Ramer–Douglas–Peucker algorithm to improve the accuracy of my curve >> simplification: >> >> http://en.wikipedia.org/wiki/Ramer%E2%80%93Douglas%E2%80%93Peucker_algorithm >> >> >> > -- > Stephen Haywood > Information Security Consultant > CISSP, GPEN, OSCP > T: @averagesecguy > W: averagesecurityguy.info > > -- - ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] How to load python code only after program startup?
Hi I use a compositing program called Nuke which loads my custom modules on start up. So if I have an error in my python code somewhere, Nuke won't open and it throws a typical error which is easy enough to fix. The problem I am running into is that when others on my network are using an older version of Nuke, some of my code causes their older version to not open. For example, recently I started using gnuplot.py for graphical feed back which the older version of Nuke doesn't like. So my question is: What is the best way to wrap all my custom code so that it isn't read on startup, but rather only after I invoke a "loadMyCustomModules.py" module. Help please:)! Pete ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
