Python Map
Map maps a function to all elements of an input list. The specification of Map is: map(function_to_apply, list_of_inputs)
Most of the time, we need to pass all the elements in the list to a function one by one and collect the output. For example:
items = [1, 2, 3, 4, 5] squared = [] for i in items: squared.append(i**2)
Using Map allows us to solve this problem in a simpler way.
items = [1, 2, 3, 4, 5] squared = list(map(lambda x: x**2, items))
Most of the time, we will use the anonymous function lambda in python to cooperate with map. Not only for a list of inputs, but we can also use it for a list of functions.
def multiply(x): return (x*x) def add(x): return (x+x) funcs = [multiply, add] for i in range(5): value = list(map(lambda x: x(i), funcs)) print(value)
The output of the above program is:
# Output: # [0, 0] # [1, 2] # [4, 4] # [9, 6] # [16, 8]
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