Interesting functions in python and interesting functions in python

Interesting functions in python and interesting functions in python

Filter (function, sequence): Execute function (item) in sequence for items in sequence, and combine items whose execution result is True into a List/String/Tuple (depending on the sequence type) return: >>> def f (x): return x % 2! = 0 and x % 3! = 0 >>> filter (f, range (2, 25) [5, 7, 11, 13, 17, 19, 23] >>> def f (x ): return x! = 'A'> filter (f, "abcdef") 'bcdef 'map (function, sequence): Execute function (item) in sequence for items in sequence ), see the execution result to form a List and return: >>> def cube (x): return x * x >>>> map (cube, range (1, 11) [1, 8, 27, 64,125,216,343,512,729,100 0] >>> def cube (x): return x + x... >>> map (cube, "abcde") ['A', 'bb ', 'cc', 'dd', 'ee'] In addition, map supports multiple sequence, this requires the function to support the corresponding number of parameter inputs: >>> def add (x, y): return x + y >>>> map (add, range (8 ), range (8) [0, 2, 4, 6, 8, 10, 12, 14] reduce (function, sequence, starting_value): calls the function sequentially for the items in sequence, if starting_value exists, it can also be called as an initial value. For example, it can be used to sum the List: >>> def add (x, y): return x + y >>> reduce (add, range (1, 11) 55 (Note: 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10) >>> reduce (add, range (1, 11), 20) 75 (Note: 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 20)

　　

How to define functions in python

Use the def keyword, which contains the parameter list in brackets.
Def add (a, B ):
Return a + B

# Call
Print add (1, 2)

What is the zip () function in python?

Zip ([1, 2, 3], ['A', 'B', 'C'])
The result is
[(1, 'A'), (2, 'B'), (3, 'C')]

Is to extract the elements of each array in sequence, and then combine
Operands can be more
Zip ([, 3], ['A', 'B', 'C'], [, 6 ])

If the element length is inconsistent, it will be cut to the same length.
In addition, zip (* list) is an asterisk in front of the array, which is the inverse operation of the above operation.
The result of zip (* [(1, 'A'), (2, 'B'), (3, 'C')]) is [1, 2, 3], ['A', 'B', 'C']