Map () function in python and map function in python

Map () function in python and map function in python

Map () is a high-order function built in Python. It receives a function f and a list, and uses function f in turn on each element of the list, get a new list and return it.

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, you only need to pass in the f (x) = x * x function to complete the computation using the map () function:

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 returns a new list.

The map () function can be used to convert a list to another list. You only need to pass in the conversion function.

Because the list element can be of any type, map () can not only process a list that only contains values, but also process a list that contains any type, as long as the input function f can process this data type.

Example:

Assume that the English name entered by the user is invalid, and the first letter is not followed by the lowercase letter rules, use the map () function to put a list (including several nonstandard English names) to a list containing standardized English names:

Input: ['Adam ', 'lisa', 'bart']
Output: ['Adam ', 'lisa', 'bart']

Method:

def format_name(s):return s.capitalize()print map(format_name, ['adam', 'LISA', 'barT'])

Result:

>>> ['Adam', 'Lisa', 'Bart']