python3-notes-c-004-functions-map, filter, reduce & lambda

f =Lambda xY, z:x + y + Z
Print (f (1,2,3))# 6
g =Lambda x, y=2, z=3:x + y + Z
Print (g (1,z=4,y=5))# 10

# lambdaExpressions are commonly used to write jump tables (Jump table), which is a list or dictionary of behaviors
L = [(Lambda x:x**2),
(Lambda x:x**3),
(Lambda x:x**4)]
Print (l[0] (2), l[1] (2), l[2] (2))# 4 8 16

D = {' F1 ':(Lambda:2 +3),
 ' F2 ':(Lambda:*3),
 ' F3 ':(Lambda:2**5);
Print (d[' F1 '] (), d[' F2 '] (), d[' F3 '] ())# 5 6 8

# map (function, sequence[, sequence, ...]) list
#Maps a function call to the corresponding element of each sequence and returns a list with all the returned values
DefInc (X, y):
 Return (x, y)
La = [1,2,3,4]
LB = [' Sun ',M,T,W,T,F,' S ']
L1 =ListMap (inc, LA, LB))# <class ' list ': [(1, ' Sun '), (2, ' M '), (3, ' T '), (4, ' W ')]
L2 =ListMap (Lambda x, y:x * y), LA, LA))#of two parameters<class ' list ';: [1, 4, 9, 16]
L3 =ListMap (Lambda x:x**2), LA))#UseLambdaForm<class ' list ';: [1, 4, 9, 16]
L4 =List (x**2For XInchRange1,5))#It's faster.<class ' list ';: [1, 4, 9, 16]
L5 =List (x+yFor XInchRange5)If X2 = =0For YInchRange10)If y%2 = =1)
 # <class ' list ';: [1, 3, 5, 7, 9, 3, 5, 7, 9, 11, 5, 7, 9, 11, 13]

# Filter (function or None, sequence), list, tuple, or string
#A given Boolean function is called for each element of a known sequence, and an element that returns a nonzero value is added to a list
DefFUN1 (x):
 If x >100:
 Return True
Else
 Return False
F1 =ListFilter (FUN1, [2, 101,  3]) # <class ' list ';: [101, 600]
F2 = List (filter (lambda x:x% 2 = = 0, LA)) # <class ' list ';: [2, 4]
F3 = List (filter (lambda x: True if (x > ' a ') else False, [' A ', ' B ', ' C ')]) # <class ' L Ist ';: [' B ', ' C ']                

# Reduce (function, sequence[, initial]), value
# (Summary: The continuation of the result and the next element of the sequence are cumulative calculations)
# functionparameter is a function with two parameters,ReduceSequentially fromSequenceTo take an element from a
#And the Last CallfunctionThe result of making the parameter call againfunction。 First time callfunctionWhen
#If you provideInitialparameter, theSequenceThe first element in theinitial call function< Span style= "COLOR: #808080", 
 #  otherwise sequence The first two elements in the parameter call function from functools import reduce 
 C = reduce (lambda x# 
 C = reduce (lambda x100)  #                 

Python3-notes-c-004-functions-map, filter, reduce & lambda