2018-6-6-python full stack development day15-part2-recursion

Recursive

Continue running functions within the function, knowing that a goal is reached and the final return value.

Characteristics of recursion:

1. The function must have a definite end condition

2. Without entering a recursion, the problem that needs to be addressed should be reduced

3. Recursive efficiency is low, need to prevent memory overflow

Class Exercises

　

1. Ask the way

　　

#Ask the way, there are several people on the road, ask if one of them knows where the place is.s1=['Alex','Xuzheng','Xiaoye','Haibin']defWenlu (S1): person=s1.pop (0)#the list of passers-by is paged out for questioning, and the list of non-questions is reduced    ifperson = ='Haibin':#only the seashore knows the way.        return 'Ah, I know how to get to the Taiping container .'    ifLen (S1) = =0:return 'no one knows where the road is.'    Print('I'm sorry, I don't know, I'll ask you.') Res=Wenlu (S1)returnResres=Wenlu (S1)Print(RES)

Very coarse recursion.

str = input (' Please enter several characters:')def  F (x):    if x = =-1:         return "'    Else :         return Str[x] + f (x-1)print(f (Len (str)-1)----Alex= = = Xela

Wrote it myself.

def Zhuan (x):     if x = = 0        :return'    else:        a=s[x-1]+zhuan (x-1 )        return  ab=Zhuan (len (s))print(b)

2018-6-6-python full stack development day15-part2-recursion