function
# One, less use of global variables
# 1. Unsafe, easy to modify
# 2. Running with in-occupied memory
# Two, the function returns multiple values, if more than one value is returned, the result of return is returned in tuple format
DefHelloABCD:
ReturnABCD
# Three, List derivation
Res= Hello (' Ybq ',' MPP ',' Zhx ',' Lby ')
Print (RES)
Nums= [0,1,3,4,5,6,7]
New_nums= [x-1For XIn Nums]
Print (new_nums)
# 四、一个 function only implements one function, the less code the better
#
# Five, constant
# A constant is a variable that does not change.
# constant names are all defined in uppercase letters.
# variable Exchange
A = 2
b = 1
# b = 1 A = 2
# b,a = A, b #交换两个变量的值
# print (A, B)
A = a + b # 3
b = a -b # 2
A = a -b # 3-2
# built-in functions
# function is variable
# len type print input str
PrintAll ([1,2,3,4]))# Determine if the values inside an iterative object are true
PrintAny ([0,1,2,3,4]))# Determine if there is a true value in an object that can be iterated
PrintBin100))# Decimal to binary binary
Ejz=Bin100)
Print (Ejz.replace (' 0b ',‘‘))# 0b characters added by default after de-binary
PrintChr65))# Print the ASCII corresponding to the number
PrintOrd' A '))# Print the ASCII code corresponding to the string
PrintDir1))# To print callable methods of incoming objects
PrintEval‘[]‘))# Execute Python code, only perform simple, define data types and operations
Code=' Def a ():p rint (' AA ') '
PrintEXEC (code))# Execute Python code
PrintSorted' 0123450 '))# Ascending
Ids= [1,2,3,4,7,8,0,-1]
PrintSorted (IDs,Reverse=true))# Descending
Round1.987123,5)# Keep a few decimals
Names= [' Little Black ',' Little White ',' Little Yellow ',' Little Green ']
Names1= [' Little Black ',' Little White ',' Little Yellow ',' Little Green ']
# Zip loop fetch number
For ID, name, sInchZip (IDs, names, names1):# cycle through several, whichever is less
Print (ID, name, s)
# Filter Loop Call function, filter only save results return True
DefFuncA:# 0 1 2
IfA%2==0:
Return True
Else
Return False
Nums= [xFor XInchRange11)]
Res=Filter (func, Nums)
PrintList (res))
# The map loop calls the function and returns the result of each call to the function in a list
All_res= []
For NumIn Nums:
Res= func (num)
All_res.append (RES)
Res=Map (func, Nums)
PrintList (res))
# function is variable
DefAdd ():
Print' Add Item ')
DefView ():
Print' View Products ')
DefDelete ():
Print' Delete Items ')
Choice=Input' Please enter select 1, 2, 3, '). Strip ()
Menu= {
' 1 ' : Add, # directly through the variable call function
' 2 ' : View,
' 3 ' : Delete
}
if choice in menu:
Span style= "Font-weight:bold" > Menu[choice] () # suitable for functions without arguments, Or the parameter is the same as the case.
else:
Print (
Python_python built-in functions