我做错了什么，这两个循环不起作用？ 链接是一个列表。

links = ['newarklongtermparking.com', 
 'www.airportparkingreservations.com', 
 'airparkparking.com', 
 'jfklongtermparking.com', 
 'book2park.com', 
 'globalairportparking.com', 
 'neworleansparking.com', 
 'parkwayparking.com', 
 'www.airportparkinginc.com', 
 'airportparkfly.com', 
 'unitedairportparking.com', 
 'www.way.com', 
 'cheapairportparking.org', 
 'wallypark.com', 
 'parkbytheports.com', 
 'www.cheapparkfly.com'] 

删除 www.

for a in links: 
    if (a[0] == a[1] == a[2] == 'w'): 
        a = a[4:] 

添加正确形式的链接

for a in links: 
    a = 'https://www.' + a 

请您参考如下方法:

您正在做的是修改循环变量。这根本不会影响列表。如果您想就地修改元素，我建议使用 enumerate，然后通过索引访问列表项:

for i, a in enumerate(links): 
    prefix = 'https://' if a.startswith('www') else 'https://www.' 
    links[i] = prefix + a 

处理后，links 的内容如下:

https://www.newarklongtermparking.com 
https://www.airportparkingreservations.com 
https://www.airparkparking.com 
https://www.jfklongtermparking.com 
https://www.book2park.com 
https://www.globalairportparking.com 
https://www.neworleansparking.com 
https://www.parkwayparking.com 
https://www.airportparkinginc.com 
https://www.airportparkfly.com 
https://www.unitedairportparking.com 
https://www.way.com 
https://www.cheapairportparking.org 
https://www.wallypark.com 
https://www.parkbytheports.com 
https://www.cheapparkfly.com