Copying a list using [:}. and trying to make everything in the new list lower case using lower() [duplicate]

First: you forgot () in value = value.upper().
Second: you need lower(), not upper().
Third: there is function list() so don't use variable list because you will have no access to function list()

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It changes to lower text in local variable value but not on list.

If you want to replace in existing list then it may need use index

copied_list[index] = copied_list[index].lower().

like

old_list = ['CAR', 'TRUCK'] copied_list = old_list[:] for index in range(len(copied_list)): copied_list[index] = copied_list[index].lower() print(copied_list)

But more popular is to create empty list and .append() new value

old_list = ['CAR', 'TRUCK'] copied_list = [] # empty list for value in old_list: copied_list.append( value.lower() ) print(copied_list)

or even as list comprehension

old_list = ['CAR', 'TRUCK'] copied_list = [value.lower() for value in old_list] print(copied_list)

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You may also use map() with str.lower (and eventually with list() if you want to see results at once - if you don't plan to use for-loop for this)

old_list = ['CAR', 'TRUCK'] copied_list = list(map(str.lower, old_list)) print(copied_list)