Built-in function Three Musketeers

map

lst = [1,2,3,4,5,6]

print(list(map(lambda x:x*x,lst)))


>>>[1, 4, 9, 16, 25, 36]

Pass in a function in the map, calculate the following loopable object, and output the result

 

filter

lst = [1,2,3,4,5,6]

print(list(filter(lambda x:x>2,lst)))

>>>[3, 4, 5, 6]

Enter a function, filter the following loopable objects, and output the results

 

reduce

import functools

lst = [1,2,3,4,5,6]

print(functools.reduce(lambda x,y:x+y,lst,999))

>>> 1020

In fact, it is 999 +21 
to achieve the cumulative effect