[python] Compare string with all values in list

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)>=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?

This question is related to python

The answer is


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:
    # ...

In Python you may use the in operator. You can do stuff like this:

>>> "c" in "abc"
True

Taking this further, you can check for complex structures, like tuples:

>>> (2, 4, 8) in ((1, 2, 3), (2, 4, 8))
True

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'}