Script Discussion & Critique

[hokiegal99]

Is there a forum where one could post a Python script and have it
critiqued by others?

Something like: Y would be more efficent if you did it this way, or
doing it that way could cause problems with X, etc.

Thanks!!!

[Peter Otten]

hokiegal99 wrote:

Thanks for any ideas, pointers or critique... most of the ideas behind
the script came from the list.
Choose variable names that make their intended purpose clear, e.g.
searchToken/replaceToken instead of x/y.
search = string.find(dat a, x)
if search >=1:

This is wrong as others have already explained. I recommend:

if searchToken in data:
# perform replacement

(I did it with .find() till yesterday, but no more! I like that Python
minimizes the need of artificial indices:-)

Factor out reusable code, e.g:

def replaceTokenInT ree(rootFolder, searchToken, replaceToken,
filterFunc=None )
def replaceTokenInF ile(filename, searchToken, replaceToken, backupFile=None )

This will pay off as your scripts grow (or your script grows:-), so make it
a habit as soon as possible.
Some observations that are not directly code-related:

You can change - and possibly corrupt - *many* files in one run of you
script. So you might add a confirmation prompt repeating searchToken,
replaceToken and the root directory (resolved to an absolute path) and -
somewhat more ambitious - a means to generate backups.

When replacement fails on one file, e. g. due to access rights, you could
catch the exception and prompt the user, if he wants to continue or abort
the script.

Chances are that there are some files in the tree that you do not want to
process, so you should add some basic filtering. The fnmatch module might
be helpful.
Last but most important:

Take time to build a test file tree, and include all special cases you can
think of (including those you consider irrelevant) e. g. files
starting/ending with search token, zerolength file, file with readonly
access.

Peter

[Ganesan R]

>>>>> "hokiegal99 " == hokiegal99 <ho********@hot mail.com> writes:

Is this script written well? Is it a good design? How could it be made
better (i.e. write to a file exactly what the scipt did)? I hope to
use it to recursively find a replace strings in all types of files
(binary and text). Thanks for any ideas, pointers or critique... most of the ideas behind
the script came from the list.
Others have done an excellent job of telling you the problems of critiquing
your code. I'll try to address one point that others haven't covered
already.
print " "
print "************** *************** *************** **********"
print " Three Easy Steps to a Recursive find and Replace "
print "************** *************** *************** **********"
print " "
x = raw_input("1. Enter the string that you'd like to find: ")
print " "
y = raw_input("2. What would you like to replace %s with: " %x)
print " "
setpath = raw_input("3. Enter the path where the prgroam should run: ")

What you've done is not wrong. But it's simpler to replace all that with

import sys
x = sys.argv[1]
y = sys.argv[2]
setpath = sys.argv[3]

so that you can run it as "python myscript.py <search> <replace> <path>".
This way you can easily call your script from another program and
makes it much more useful. You can do something like

if len(sys.argv) >= 1:
x = sys.argv[1]
y = sys.argv[2]
setpath = sys.argv[3]
else:
raw_input(...)
...

and get the best of both worlds.

Ganesan

--
Ganesan R

[hokieghal99]

Ganesan R wrote:

Others have done an excellent job of telling you the problems of critiquing
your code. I'll try to address one point that others haven't covered
already.

What you've done is not wrong. But it's simpler to replace all that with

import sys
x = sys.argv[1]
y = sys.argv[2]
setpath = sys.argv[3]

so that you can run it as "python myscript.py <search> <replace> <path>".
This way you can easily call your script from another program and
makes it much more useful. You can do something like

if len(sys.argv) >= 1:
x = sys.argv[1]
y = sys.argv[2]
setpath = sys.argv[3]
else:
raw_input(...)
...

I don't understand this approach to developing a script. I think this is
more of a true program than a script... it's much more complex. My
background is shell scripting so I'm limited to what I've learned from
that. Python is much deeper than that, but I'm learning. Thank you for
the advice.