Python path-function return value returns

return keyword

　　No return value

Returns a value

Return multiple values

1. No return value

----does not write return, it returns a none by default: The following function does not write return, which is a case where there is no return value.

#function DefinitiondefMylen ():"""calculate the length of a S1"""S1="Hello World"length=0 forIinchS1:length= Length+1Print(length)#function CallStr_len =Mylen ()#because there is no return value, the Str_len is none at this timePrint('Str_len:%s'%str_len)

-----Write only return, not write anything else, will return none, since there is no value to return, can not write return, why do you want to write a return? Here we have to talk about the other uses of return, that is, once the return is encountered, the entire function is terminated

def Ret_demo ():     Print (111)     return    Print (222= Ret_demo ()print(ret)

------return None: As in the above two cases, we generally do not write

def Ret_demo ():     Print (111)     return None     Print (222= Ret_demo ()print(ret)

return None

2. Returns a value

Just write what you want to return after return.

#function DefinitiondefMylen ():"""calculate the length of a S1"""S1="Hello World"length=0 forIinchS1:length= Length+1returnlength#function CallStr_len =Mylen ()Print('Str_len:%s'%str_len)

returns a value

3. Return multiple values

--- can return any number of values of any data type, with a value that receives

deffunc1 ():return1,2,3,4defFunc2 ():return1, (+), [3,4],{'name':'Nancy'}L1=func1 () L2=Func2 ()Print(L1)#(1, 2, 3, 4)Print(L2)#(1, (1, 2), [3, 4], {' name ': ' Nancy '})

return multiple values

--- returns any number of values of any data type, received with multiple values

deffunc1 ():return1,2,3,4defFunc2 ():return1, (+), [3,4],{'name':'Nancy'}L1=func1 () a,b,c,d=Func2 ()Print(L1)#(1, 2, 3, 4)Print(a,b,c,d)#1 (1, 2) [3, 4] {' name ': ' Nancy '}

receive with multiple values

----Cause Analysis

>>>#in Python, multiple values separated by commas are considered to be a tuple. (1, 2)>>> 1,2,3,4(1, 2, 3, 4)>>> (1,2,3,4)(1, 2, 3, 4)#Sequence Decompression One>>> a,b,c,d = (1,2,3,4)>>>a1>>>b2>>>C3>>>D4#Sequence Decompression Two>>> a,_,_,d= (1,2,3,4)>>>a1>>>D4>>> a,*_= (1,2,3,4)>>> *_,d= (1,2,3,4)>>>a1>>>D4#also applies to strings, lists, dictionaries, collections>>> A, B = {'name':'Eva',' Age': 18} >>>a'name'>>>b' Age'

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Python path-function return value returns