Convert a Python list with strings all to lowercase or uppercase

python list
user219126 picture user219126 · Nov 26, 2009 · Viewed 533k times · Source

I have a python list variable that contains strings. Is there a python function that can convert all the strings in one pass to lowercase and vice versa, uppercase?

Answer

YOU picture YOU · Nov 26, 2009

It can be done with list comprehensions. These basically take the form of [function-of-item for item in some-list]. For example, to create a new list where all the items are lower-cased (or upper-cased in the second snippet), you would use:

>>> [x.lower() for x in ["A","B","C"]]
['a', 'b', 'c']

>>> [x.upper() for x in ["a","b","c"]]
['A', 'B', 'C']

You can also use the map function:

>>> map(lambda x:x.lower(),["A","B","C"])
['a', 'b', 'c']
>>> map(lambda x:x.upper(),["a","b","c"])
['A', 'B', 'C']

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