# Multiple operations for each number in the python square list

Time：2021-10-18

## map

`map(function,iterable)`

1. x = [1,2,3,4,5]
2. def square(num):
3. return num*num
4. print(list(map(square,x)))
5. #output:[1, 4, 9, 16, 25]

## lambda

`lambda x:`

1. x = [1,2,3,4,5]
2. print(list(map(lambda num:num*num, x)))
3. #output:[1, 4, 9, 16, 25]

## list comprehensions

`[funtion for item in iterable]`

1. print([ num*num for num in [1,2,3,4,5]])
2. #output:[1, 4, 9, 16, 25]

Supplement: several methods of finding the square root and square of numbers in Python

## Method 1: use the built-in module

1. >>> import math
2.
3. >>>Math. Pow (12, 2) # square
4. 144.0
5.
6. >>>Math. Sqrt (144) # find the square root
7. 12.0
8.
9. >>>

## Method 2: use expression

1. >>>12 * * 2 # square
2. 144
3.
4. >>>144 * * 0.5 # find square root
5. 12.0
6.
7. >>>

## Method 3: use built-in functions

1. >>>Pow (12, 2) # square
2. 144
3.
4. >>>Pow (144,. 5) # find the square root
5. 12.0
6.
7. >>>

The above is personal experience. I hope you can give us a reference and support us. If you have any mistakes or don’t consider completely, please don’t hesitate to comment.