The map () function in Python

Map () is a Python built-in high-order function that receives a function f and a list, and then, by putting the function f on each element of the list in turn, gets a new list and returns.

Map () is a Python built-in high-order function that receives a function f and a list, and then, by putting the function f on each element of the list in turn, gets a new list and returns.

For example, for list [1, 2, 3, 4, 5, 6, 7, 8, 9]

If you want to square each element of the list, you can use the map () function:

Therefore, we only need to pass in the function f (x) =x*x, we can use the map () function to complete this calculation:

def f (x):     return x*xprint map (f, [1, 2, 3, 4, 5, 6, 7, 8, 9])

Output Result:

[1, 4, 9, 10, 25, 36, 49, 64, 81]

Note: the map () function does not change the original list, but instead returns a new list.

With the map () function, you can convert a list to another list, just pass in the conversion function.

Because the list contains elements that can be of any type, map () can not only handle lists that contain only numeric values, but in fact it can handle lists of any type, as long as the incoming function f can handle the data type.

Example:

Assuming that the user entered the English name is not standard, not according to the first letter capitalization, subsequent letter lowercase rules, please use the map () function, a list (including a number of nonstandard English names) into a list containing the canonical English name:

Input: [' Adam ', ' Lisa ', ' Bart '] output: [' Adam ', ' Lisa ', ' Bart ']

Method:

def Format_name (s):return s.capitalize ()print map (format_name, ['Adam'LISA' BarT'])          

Results:

['Adam'Lisa'Bart']

Reference from: http://www.cnblogs.com/Lambda721/p/6128351.html

The map () function in Python