Python provides 3 useful global functions we can use to work with collections:
Tip: sometimes list comprehensions make more sense and are generally considered more pythonic
map() is used to run a function upon each item in an iterable item like a list, and create a new list with the same number of items, but the values of each item can be changed.
map() being used to double each item in a list:
numbers = [1, 2, 3] def double(a): return a * 2 result = map(double, numbers)
When the function is a one-liner, it’s common to use a lambda function:
numbers = [1, 2, 3] double = lambda a : a * 2 result = map(double, numbers)
and even inline it:
numbers = [1, 2, 3] result = map(lambda a : a * 2, numbers)
The original list is left untouched, and a new list with the updated values is returned by
The result is a map object, an iterable, and you will need to cast it to a
list to print its content:
print(list(result)) # [2, 4, 6]
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