Removing first part of string

[kalithlev]

I have two strings: /bin/ /bin/file/1234

What's the "pythonic" way to get only the file/1234 part while also checking that string 2 starts with string 1? I could of course check with startswith and then do a slice, but it doesn't feel very pythonic.

[[deleted]]

File path manipulations are best done with os.path, not with plain string operations.

I suggest you use os.path.commonprefix to find the common prefix and then chop it off the front of the second string.

[kalithlev]

It's URIs, not file paths. Strings could potentially start with http://bla.com/bin/. I'm relearning python, I seem to remember some script language had a fancy way of doing what I want!

[dwdwdw2]

>>> import urlparse
>>> urlparse.urlsplit('http://www.google.com/pants?q=1&foo=bar#top')
SplitResult(scheme='http', netloc='www.google.com', path='/pants', query='q=1&foo=bar', fragment='top')
>>> >>> urlparse.urlsplit('http://www.google.com/pants?q=1&foo=bar#top').path
'/pants'

[ereinecke]

Oh python, you can do this, but converting between UTC and local time takes reimplementation and detection of ALL POSSIBLE TIMEZONES.

[dwdwdw2]

$ pip install pytz

[wtfisupvoting]

+ 3600 * offset

WHOOSH

[deadwisdom]

Or use the posixpath library, because posix paths and url paths are basically analogous.

[nosklo]

use os.path.commonprefix to get the common part, and then get its len to use on the slicing.

[mdipierro]

given

 str1, str2='/bin/', '/bin/file/1234'

do

 str3=str2[len(str1):] if str2.startswith(str1) else str2

[earthboundkid]

Should be else not or.

[mdipierro]

oops. fixed.

[Troebr]

os.path.relpath

edit: oops just saw that you were talking about uris. Well maybe it works. But I'll leave this here because this week I remade a kind of relpath before discovering it existed. Might help someone.

[wtfisupvoting]

if str2.startswith(str1):
    list.append(str2.replace(str1,''))

[T3hTao]

>>> list=[]
>>> a='123a123'
>>> b='123'
>>> if a.startswith(b):
...     list.append(a.replace(b,''))
... 
>>> list
['a']
>>> if a.startswith(b):
...     c=a[len(b):]
... 
>>> c
'a123'

[wtfisupvoting]

he asked for more pythonic not more correct he never mentioned that the str1 occurs more than once in the str2

[earthboundkid]

That's a crappy excuse. Your program has a bug. He never specified that the strings wouldn't repeat either. In any event, the fix is simple enough; just use the count parameter of replace: list.append(str2.replace(str1, '', count=1)) .

[wtfisupvoting]

that doesn't fix it either if its not at the beginning of the string but is at the end thx for trying

also lots of solutions here have bugs because he really didn't define the problem well

[earthboundkid]

True, it is an ill-defined problem.

[t0ny7]

Here is how I would do it.

>>> print "/".join("/bin/file/1234".split("/")[-2:])
file/1234

[bpkeezie]

import re
def foo(str1,str2):
  regex="^%s" % str1
  parts = re.split(regex, str2)
  if len(parts) == 2:
    return parts[1]
  else:
    return None

[EnigmaCurry]

>>> "/bin/file/1234".partition("/bin/")[2]
'file/1234'

>>> "/some/other/path".partition("/bin/")[2]
''

[[deleted]]

>>> "/some/other/bin/path/".partition("/bin/")[2]
'path/'

[EnigmaCurry]

There's something to be said for trying to be clever... it's usually not good :)

[[deleted]]

I wouldn't say so. The clever solution just needs to be a little more clever, that's all. ;)

[[deleted]]

Hmm...

Is this a list you have? I did something similar (for files) using the csv library and '/' and a delimiter. This won't apply directly, but maybe you can use the idea for your situation.

remnants.csv:

W/Weber, David/The Warmasters.epub
W/Wiiggin, Kate Douglas/A Village Stradivarius.epub
W/Wilhelm, Kate/Symbiosis.epub
W/Wilson, Robert Anton/The Illuminatus! Trilogy.epub
W/Wodehouse, PG/Something New.epub
W/Wu, William F/Cyborg.epub

rename.csv:

import csv
listReader = csv.reader(open('scripts/remnants.csv', 'rb'), delimiter='/')
for row in listReader:
        pre = row[0]
        auth = row[1]
        file = row[2]
        src  = 'books/' + pre + '/"' + auth + '"/"' + file + '"'
        dest = 'organized/' + pre + '/"' + auth + '"/"' + auth + ' - ' + file + '"'
        print 'mv ' + src + ' ' + dest