Compare string with all values in list

Question

I am trying to fumble through python  and learn the best way to do things  I have a string where I am doing a compare with another string to see if there is a match  if paid j  find d  gt  0       BLAH BLAH  If d were an list  what is the most efficient way to see if the string contained in paid j  has a match to any value in d

User · Answer

In Python you may use the in operator  You can do stuff like this    gt  gt  gt   c  in  abc  True   Taking this further  you can check for complex structures  like tuples    gt  gt  gt   2  4  8  in   1  2  3    2  4  8   True

User · Answer

I assume you mean list and not array  There is such a thing as an array in Python  but more often than not you want a list instead of an array   The way to check if a list contains a value is to use in   if paid j  in d

User · Answer

for word in d      if d in paid j            do something     will try all the words in the list d and check if they can be found in the string paid j    This is not very efficient since paid j  has to be scanned again for each word in d  You could also use two sets  one composed of the words in the sentence  one of your list  and then look at the intersection of the sets   sentence    words don t come easy  d     come    together    easy    does    it    s1   set sentence split    s2   set d   print  s1 intersection s2     Output     come    easy

User · Answer

If you only want to know if any item of d is contained in paid j   as you literally say   if any x in paid j  for x in d         If you also want to know which items of d are contained in paid j    contained    x for x in d if x in paid j     contained will be an empty list if no items of d are contained in paid j    There are other solutions yet if what you want is yet another alternative  e g   get the first item of d contained in paid j   and None if no item is so contained    firstone   next  x for x in d if x in paid j    None    BTW  since in a comment you mention sentences and words  maybe you don t necessarily want a string check  which is what all of my examples are doing   because they can t consider word boundaries -- e g   each example will say that  cat  is in  obfuscate   because   obfuscate  contains  cat  as a substring    To allow checks on word boundaries  rather than simple substring checks  you might productively use regular expressions    but I suggest you open a separate question on that  if that s what you require -- all of the code snippets in this answer  depending on your exact requirements  will work equally well if you change the predicate x in paid j  into some more sophisticated predicate such as somere search paid j   for an appropriate RE object somere   Python 2 6 or better -- slight differences in 2 5 and earlier    If your intention is something else again  such as getting one or all of the indices in d of the items satisfying your constrain  there are easy solutions for those different problems  too    but  if what you actually require is so far away from what you said  I d better stop guessing and hope you clarify -

[python] Compare string with all values in list

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