在python3中声明后未定义函数

Question

Using python 3: I have three functions: montePi, isInCircle and main. I need to have the isInCircle called by montePi. The function will work, it just says that isInCircle is not defined. How can I define it?

import random
import math

def montePi(numDarts):

    inCircle = 0

    def isInCircle(x, y, r):
        r = 1
        d = math.sqrt(x**2 + y**2)
        if d <= r:
            return True
        else:
            return False

    for i in range(numDarts):
        x = random.random()
        y = random.random()
        d = math.sqrt(x**2 + y**2)
        if d <= 1:
            inCircle = inCircle +1
        pi = inCircle / numDarts * 4
    return pi

def main():
    print(montePi(100))
    print(montePi(1000))
    print(montePi(10000))
    print(montePi(100000))
main()

Answer 1

Because function isInCircle is defined in montePi , it can be called within montePi but not other functions as it is local. If you define isInCircle outside of montePi then you'll be able to call it from main .

Not sure what you're trying to program here, but there seems to be a chance that this question , regarding functions within functions can help you decide what you want here. Here is a question that covers how scopes work.

Should you need to call isInCircle from main or outside main , then this is how it should be formatted;

import random
import math

def isInCircle(x, y, r):
    r = 1
    d = math.sqrt(x**2 + y**2)
    if d <= r:
        return True
    else:
        return False

def montePi(numDarts):

    inCircle = 0

    for i in range(numDarts):
        x = random.random()
        y = random.random()
        d = math.sqrt(x**2 + y**2)
        if d <= 1:
            inCircle = inCircle +1
        pi = inCircle / numDarts * 4
    return pi

def main():
    print(montePi(100))
    print(montePi(1000))
    print(montePi(10000))
    print(montePi(100000))
main()