Fix Python – list.index() function for Python that doesn’t throw exception when nothing found

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Question

Asked By – Yarin

Python’s list.index(x) throws an exception if the item doesn’t exist. Is there a better way to do this that doesn’t require handling exceptions?

Now we will see solution for issue: list.index() function for Python that doesn’t throw exception when nothing found

Answer

If you don’t care where the matching element is, then use:

found = x in somelist

If you do care, then use a LBYL style with a conditional expression:

i = somelist.index(x) if x in somelist else None

This question is answered By – Raymond Hettinger

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