How to check if a string contains an element from a list in Python

Question

I have something like this   extensionsToCheck      pdf     doc     xls    for extension in extensionsToCheck      if extension in url string          print url string    I am wondering what would be the more elegant way to do this in Python  without using the for loop   I was thinking of something like this  like from C C     but it didn t work   if    pdf  or   doc  or   xls   in url string      print url string    Edit  I m kinda forced to explain how this is different to the question below which is marked as potential duplicate  so it doesn t get closed I guess      The difference is  I wanted to check if a string is part of some list of strings whereas the other question is checking whether a string from a list of strings is a substring of another string  Similar  but not quite the same and semantics matter when you re looking for an answer online IMHO  These two questions are actually looking to solve the opposite problem of one another  The solution for both turns out to be the same though

User · Answer

This is a variant of the list comprehension answer given by @psun.

By switching the output value, you can actually extract the matching pattern from the list comprehension (something not possible with the any() approach by @Lauritz-v-Thaulow)

extensionsToCheck = ['.pdf', '.doc', '.xls']
url_string = 'http://.../foo.doc'

print [extension for extension in extensionsToCheck if(extension in url_string)]

['.doc']`

You can furthermore insert a regular expression if you want to collect additional information once the matched pattern is known (this could be useful when the list of allowed patterns is too long to write into a single regex pattern)

print [re.search(r'(\w+)'+extension, url_string).group(0) for extension in extensionsToCheck if(extension in url_string)]

['foo.doc']

User · Answer

Use list comprehensions if you want a single line solution  The following code returns a list containing the url string when it has the extensions  doc   pdf and  xls or returns empty list when it doesn t contain the extension    print  url string for extension in extensionsToCheck if extension in url string     NOTE  This is only to check if it contains or not and is not useful when one wants to extract the exact word matching the extensions

User · Answer

It is better to parse the URL properly - this way you can handle http       file doc foo and http       foo doc file exe correctly   from urlparse import urlparse import os path   urlparse url string  path ext   os path splitext path  1  if ext in extensionsToCheck    print url string

User · Answer

Check if it matches this regex       pdf    doc    xls      Note  if you extensions are not at the end of the url  remove the   characters  but it does weaken it slightly

User · Answer

extensionsToCheck      pdf     doc     xls     test doc  endswith extensionsToCheck      returns True   test jpg  endswith extensionsToCheck      returns False

User · Answer

Use a generator together with any  which short-circuits on the first True   if any ext in url string for ext in extensionsToCheck       print url string    EDIT  I see this answer has been accepted by OP  Though my solution may be  good enough  solution to his particular problem  and is a good general way to check if any strings in a list are found in another string  keep in mind that this is all that this solution does  It does not care WHERE the string is found e g  in the ending of the string  If this is important  as is often the case with urls  you should look to the answer of  Wladimir Palant  or you risk getting false positives

[python] How to check if a string contains an element from a list in Python

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