Python function VII (built-in function)

One. Built-in functions

1. Important built-in functions

　　Are all with key: Max min Map filter returns an iterator

Sorted returns the list function name after the

1.1 Max

DIC = {'K1': 20,'K2': 30,'K3': 100}deffunc (x):returnDIC[X]L1= Max (Dic,key=func,)#(the output is that DIC defaults to the output of DIC's key), the function returns a value, that is, the key to select the largest valuePrint(L1)#K3DiC= {3:20,2:30,1:100}deffunc (x):returnXL1= Max (Dic,key=func,)#(the output is that DIC defaults to the output of DIC's key), the function returns the key value, that is, the largest key is selectedPrint(L1)#3

1.2 Zip allows you to place multiple, iterative objects with a minimum number of iterations to return an iterator ( zipper method)

L1 = [1,2,3,4,5]l2= ['Wusir','Alex','Taibai']l3= ['*',"**"]Print(Zip (L1,L2))#<zip object at 0x00000161edc19f08> forIinchZip (l1,l2,l3):Print(i) Results: (1,'Wusir','*')(2,'Alex','**')

1.3 Map

Print([I*i forIinchRange (5)])#[0, 1, 4, 9, +]Print(Map (abs,[1,2,3,-4,-5,-7]))#<map object at 0x0000015b0dcc75c0> iterator forIinchMap (abs,[1,2,3,-4,-5,-7]):#ABS is built-in function, absolute value    Print(i)defFunc (x):returnx*x forIinchMap (Func,range (5)):#Func is a function of its own writing.    Print(i)defFunc (x):returnx*x forIinchMap (func,[0,1,2,3,4]):    Print(i)

1.4 Filter filters out eligible element outputs

Print  for inch if i% 2 = = 0]    #[2, 4]def func1 (x):return x% 2 = 0for in filter (func1,[1,2,3,4,5]):    print(i)#  Result:  #  2#  4

1.5 sorted returns a list, forms a new list, and returns

List.sort () Change the original list

L1 = [1,4,3,5,7,8]Print(Sorted (L1,))#[1, 3, 4, 5, 7, 8]L= ['FSDAFSA','Fddsaf','QQQ','FGASJDLG;DSJFG']deffunc1 (x):returnlen (x)Print(Sorted (L,key=len))#[' QQQ ', ' fddsaf ', ' FSDAFSA ', ' FGASJDLG;DSJFG '] forIinchSorted (l,key=func1):Print(i)

2. Introduction to the rest of the built-in functions

2.1 # All

Print (Any ([' ', 1,0]))     # true        any at least one element is true and returns true  similar to orprint(All ([', 1,0]))     #  False       All elements are true and return true     similar to and

2.2 Ord input character, return Unicode corresponding encoding location

CHR input encoding position, return Unicode corresponding character

#Print (Ord (' A '))#Print (ord (' B '))#Print (Ord (' Medium '))#Results:# the#98#20013Print(Chr (97))#aPrint(Chr (20013))#inPrint(ASCII ('a'))#' A 'Print(ASCII ('Country'))#\U56FD

2.3%r repr True Colours

' alex%r '% ('sb')print(name)                 #Alex ' sb ' Print (Repr ('[up]'))       # ' [up] '

2.4 Slice () slice

L1 = [11,22,33,44]print(l1[1::2= Slice (1,4,2)      # name a rule, after the slice  Print(L1[SL])

2.5 reversed () forms a new iterator.

L1 = [11,33,22,44,'Alex']l1.reverse ()print(L1)      #[' Alex ', A, a, a, a, a.   change is the original list, can only print the original list L2 = reversed (L1)    # This is an iterator iteratorfor   in L2:    print(i)

Two. anonymous functions

Typically used in conjunction with built-in functions

Format: Lambda x:x

L1 = ['234',' A','Fsdafa','Fdsagag']defFunc1 (x):returnX% 2 = =0 forIinchFilter (func1,[1,2,3,4,5]):    Print(i)#2 4 forIinchFilterLambdaX:len (x) >= 3,['234',' A','Fsdafa','Fdsagag']):    Print(i)#234 Fsdafa Fdsagag

Python function VII (built-in function)