.join()方法到底做什么? [英] What exactly does the .join() method do?

问题描述

我刚接触Python，对.join()完全感到困惑，我读过的.join()是连接字符串的首选方法.

I'm pretty new to Python and am completely confused by .join() which I have read is the preferred method for concatenating strings.

我尝试过:

strid = repr(595)
print array.array('c', random.sample(string.ascii_letters, 20 - len(strid)))
    .tostring().join(strid)

有类似的东西:

5wlfgALGbXOahekxSs9wlfgALGbXOahekxSs5

为什么这样工作? 595不应该被自动添加吗?

Why does it work like this? Shouldn't the 595 just be automatically appended?

推荐答案

仔细查看您的输出:

5wlfgALGbXOahekxSs9wlfgALGbXOahekxSs5
^                 ^                 ^

我突出显示了原始字符串的"5"，"9"，"5". Python join() 方法是字符串方法，它采用与字符串连接的事物的 list .一个更简单的示例可能有助于解释:

I've highlighted the "5", "9", "5" of your original string. The Python join() method is a string method, and takes a list of things to join with the string. A simpler example might help explain:

>>> ",".join(["a", "b", "c"])
'a,b,c'

在给定列表的每个元素之间插入，".在您的情况下，您的列表"是字符串表示形式"595"，它被视为列表["5"，"9"，"5"].

The "," is inserted between each element of the given list. In your case, your "list" is the string representation "595", which is treated as the list ["5", "9", "5"].

您似乎正在寻找+，而不是:

It appears that you're looking for + instead:

print array.array('c', random.sample(string.ascii_letters, 20 - len(strid)))
.tostring() + strid

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