description
map () will do the mapping function in accordance with the specified sequence provided.
The first parameter argument function to call the function function of each element in the sequence, each time the function returns a new list of function return values.
grammar
map () function syntax:
map(function, iterable, …)
parameter
function -- 函数
iterable -- 一个或多个序列
return value
Python 2.x return list.
Python 3.x returns an iterator.
Examples
The following example shows a map () method is used:
>>> def square (x): # calculate the number of squares
… return x ** 2
…
>>> map (square, [1,2,3,4,5]) # calculates the square of each element of the list
[1, 4, 9, 16, 25]
map (lambda x: x ** 2 , [1, 2, 3, 4, 5]) # lambda anonymous function using
[1, 4, 9, 16, 25]
Two lists, a list of data of the same position are summed
>>> map(lambda x, y: x + y, [1, 3, 5, 7, 9], [2, 4, 6, 8, 10])
[3, 7, 11, 15, 19]