L = ["Hello", "World", 18, "Apple", None]
print(
[s.lower() for s in L if isinstance(s, str)]
) the above code changes all strings in a list to lowercase
output: ["hello"," world", "apple"]
the result I expect is ["hello"," world", 18, "apple", None]
that is to keep all the contents in it. What should I do
because you add if isinstance (s, str) and you drop all the non-string Filter, you can put the condition first:
[s.lower() if isinstance(s, str) else s for s in L]add that although python's list supports any type, I personally think that all elements in list should be of the same type
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