CODEWITHSUNDEEP
pythonlambdafilter
DQI
DQI

Reputation: 785

python code with lambda and filter

Can anyone help me understand the following piece of python code:

for i, char in filter(lambda x: x[1] in str1, enumerate(str2)):
    # do something here ...

str1 and str2 are strings, I sort of understand that the "lambda x: x[1] in str1" is filtering condition, but why x[1] ?

How can I convert this for loop into a lower level (but easier to understand) python code ?

Thanks

Upvotes: 2

Views: 149

Answers (2)

Karin
Karin

Reputation: 8610

This appears functionality equivalent to:

for i, char in enumerate(str2):
    if char in str1:
        # do something here

filter is taking a list of tuples consisting of the index and elements of str2, filtering out those elements that do not appear in str1, then returning a iterable of the remaining indices and elements from str2.

Upvotes: 4

njzk2
njzk2

Reputation: 39403

Because of enumerates.

Enumerates returns tuples of (index, value) for an iterable of values.

x is a tuple of index, char.

I would write lambda (index, char): char in str1 for clarity

Upvotes: 0

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