python - 为什么请求返回 "None"？

Question

import requests

def get(url):
    if url[:7] == 'http://':
        if url[7:11] == 'www.':
            print url
            response = requests.get(url)
            if response.status_code == 200:
                return 'ok'

            else:
                return 'error'
        else:
            print(url)
            url = 'http://www.' + url[7:]
            get(url)
    else:
        print(url)
        url = 'http://' + url
        get(url)

print get('example.com')

谁能告诉我为什么这段代码返回“无”

Answer 1

您不会从对 get() 函数的递归调用中返回结果。

您需要返回递归调用 get() 函数的结果，示例 -

import requests

def get(url):
    if url[:7] == 'http://':
        if url[7:11] == 'www.':
            print url
            response = requests.get(url)
            if response.status_code == 200:
                return 'ok'

            else:
                return 'error'
        else:
            print(url)
            url = 'http://www.' + url[7:]
            return get(url)
    else:
        print(url)
        url = 'http://' + url
        return get(url)

print get('example.com')