Question

我有一个类似的元组

a = (1,2,3,4).

是否可以将元组更改为

a = [('roll', 1),('roll',2),('roll', 3),('roll', 4)]

Answer 1

这里的列表理解很简单-

string sb = "Invoice #:" +
                "1267" +
                "<br>" +
                "Date:" +
                "4/16/2018 10:44:00 AM" +
                "<br>" +
                "PO #:" +
                "<br>" +
                "Reference:" +
                "<br>" +
                "Countermen:" +
                "A/A";

var matches = Regex.Match(sb,
    @"Invoice #:\s*(.*?)\s*<br>\s*Date:\s*(.*?)\s*<br>\s*PO #:\s*(.*?)\s*<br>\s*Reference:\s*(.*?)\s*<br>\s*Countermen:\s*(.*?)\s*$");

if (!matches.Success)
{
    throw new Exception("Unable to parse");
}

var invoice = matches.Groups[1].Value;
var date = matches.Groups[2].Value;

OP

a = [("roll", i) for i in a]

有关列表理解here

的更多信息

Answer 2

是-只需执行list comprehension：

CREATE FUNCTION ... AS

请注意，这样做会重新绑定 a = [('roll', i) for i in a]！（请参阅@ShadowRanger的注释。）

Answer 3

轻松。使用a list comprehension：

a = [("roll", x) for x in a]

或with itertools stuff：

import itertools

a = list(zip(itertools.repeat('roll'), a))  # No need to wrap in list if you'll iterate the result and discard it

Answer 4

您还可以使用map函数：

i = (1,2,3,4)
list(map(lambda x: ('roll',x), i))

Answer 5

或使用list（）的另一种选择

 list(zip(["roll"]*4, a))

python中的元组转换到列表

5 个答案: