Restart function in python

问题

I am trying to make a restart function, so that when you have the answer of the function you can choose to get a new answer with new numbers or just close it.

i tried with def main() and then in the end again with main() but it is not working.

so i have made after the ,answer print, a restart function with my yeslist. , but beacuse i dont know what to fill in, under if restart in yeslist i cant get my restart. So how may i manage this?

   #import required modula
#import math
#from math import sin, pi
import math

#list for answers 
yeslist = ["yes", "y", "yeah" , "oke"]
#function to calculate x**3
def f(x):
    u = x**3
    return(u)
    #return math.sqrt(x) #function 
     #Function



#function for taking positive integer only
def positiveinput(message):
    while True:
        try:
            u= int(input(message))
            if u<= -1:
                raise ValueError
            #return the value of u
            elif u>=0:
                return u
            break
        except ValueError:
            print("oops!! That was no valid number. Try again... ")

a = positiveinput("What is the lowerlimit?:") #2

b = positiveinput("What is the upperlimit?:") #6

n = positiveinput("How many division intervals do you want?:")


#formula to calculate dx
dx = float ((b-a)/n)
xi = a;
Sum = 0;
for i in range(n):
    xi = xi+dx
    Sum = Sum + f(xi)
    #to get only the answer instead of (n * answers)
    if i==n-1:
        print("The surface under the line is %.2f"%(Sum*dx))

        restart= input ("do you want to start again")
        if restart in yeslist :
            input()
        else:
            exit()

回答1:

You should put all the code you want to repeat in a while loop.

#import required modula
#import math
#from math import sin, pi
import math

#list for answers 
yeslist = ["yes", "y", "yeah" , "oke"]
#function to calculate x**3
def f(x):
    u = x**3
    return(u)
    #return math.sqrt(x) #function 
     #Function



#function for taking positive integer only
def positiveinput(message):
    while True:
        try:
            u= int(input(message))
            if u<= -1:
                raise ValueError
            #return the value of u
            elif u>=0:
                return u
            break
        except ValueError:
            print("oops!! That was no valid number. Try again... ")

restart = "yes"
while restart in yeslist:
    a = positiveinput("What is the lowerlimit?:") #2

    b = positiveinput("What is the upperlimit?:") #6

    n = positiveinput("How many division intervals do you want?:")


    #formula to calculate dx
    dx = float ((b-a)/n)
    xi = a;
    Sum = 0;
    for i in range(n):
        xi = xi+dx
        Sum = Sum + f(xi)
        #to get only the answer instead of (n * answers)
        if i==n-1:
            print("The surface under the line is %.2f"%(Sum*dx))

            restart = input("do you want to start again")

exit()

回答2:

to repeat a process you want to follow this general framework.

define your desired/acceptable responses
set your input variable to something in your accepted responses
start a loop while your input variable is in your responses
inside the loop do your process
last thing in you loop, get input from the user to use for determining whether to continue.

    yeslist = ['y','yes','more']
    continue = 'y'
    while continue in yeslist:
        '''do your process here'''
        continue = input("another?")

回答3:

This will solve your problem. Just add while True, so that it starts again once all I/Os are complete. Hope it helped.

import math

#list for answers 
yeslist = ["yes", "y", "yeah" , "oke"]
#function to calculate x**3
def f(x):
    u = x**3
    return(u)
    #return math.sqrt(x) #function 
     #Function

#function for taking positive integer only
def positiveinput(message):
    while True:
        try:
            u= int(input(message))
            if u<= -1:
                raise ValueError
            #return the value of u
            elif u>=0:
                return u
            break
        except ValueError:
            print("oops!! That was no valid number. Try again... ")


while True:
    a = positiveinput("What is the lowerlimit?:") #2

    b = positiveinput("What is the upperlimit?:") #6

    n = positiveinput("How many division intervals do you want?:")

    #formula to calculate dx
    dx = float ((b-a)/n)
    xi = a;
    Sum = 0;
    for i in range(n):
        xi = xi+dx
        Sum = Sum + f(xi)
        #to get only the answer instead of (n * answers)
        if i==n-1:
            print("The surface under the line is %.2f"%(Sum*dx))

回答4:

Some things first:

You dont need ; in Python
You dont need the brakets when doing a return

Its simple, you can just put the "main" program in a while Loop and break if you want to leave.

One problem: You have 2 loops now (while and for). So what I did is added a boolean (do_break). If its true, the game ends:

# imports, functions and so on here
while True:
    a = positiveinput("What is the lowerlimit? ")  # 2
    b = positiveinput("What is the upperlimit? ")  # 6
    n = positiveinput("How many division intervals do you want? ")

    do_break = False

    # formula to calculate dx
    dx = float((b - a) / n)
    xi = a
    Sum = 0

    for i in range(n):
        xi = xi + dx
        Sum = Sum + f(xi)
        # to get only the answer instead of (n * answers)
        if i == n - 1:
            print("The surface under the line is %.2f" % (Sum * dx))

            restart = input("Do you want to start again? ")
            if not restart in yeslist:
                # if your input is NOT in yeslist, break
                do_break = True
                break  # Leave the for loop

    # If its breaked it now continues here
    if do_break:
        break  # Break again to leave while loop too

Edit:

I would NOT recommend doing it with functions, because of recursion!

来源：https://stackoverflow.com/questions/62248430/restart-function-in-python

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python

restart