JavaScript和Python中的分号有什么区别? [英] What is the difference between semicolons in JavaScript and in Python?

问题描述

Python和JavaScript都允许开发人员使用或省略分号.但是，我经常看到它(在书和博客中)建议我不应该在Python中使用分号，而应该始终在JavaScript中使用分号.

Python and JavaScript both allow developers to use or to omit semicolons. However, I've often seen it suggested (in books and blogs) that I should not use semicolons in Python, while I should always use them in JavaScript.

语言在使用分号之间有技术上的区别吗?还是仅仅是文化上的区别?

Is there a technical difference between how the languages use semicolons or is this just a cultural difference?

推荐答案

Python中的分号是完全可选的(当然，除非您想在一行中包含多个语句).我个人认为，每条语句末尾带有分号的Python代码看起来非常难看.

Semicolons in Python are totally optional (unless you want to have multiple statements in a single line, of course). I personally think Python code with semicolons at the end of every statement looks very ugly.

现在在Javascript中，如果您不写分号，则会在行尾自动插入 ¹ .这可能会导致问题.考虑:

Now in Javascript, if you don't write a semicolon, one is automatically inserted¹ at the end of line. And this can cause problems. Consider:

function add(a, b) {
  return
    a + b
}

您可能会认为这会返回 a + b ，但是Javascript却使您不胜其烦，并将其视为:

You'd think this returns a + b, but Javascript just outsmarted you and sees this as:

function add() {
  return;
    a + b;
}

改为返回 undefined .

¹ 参见第27页，项目7.9-

¹ See page 27, item 7.9 - Automatic Semicolon Insertion on ECMAScript Language Specification for more details and caveats.

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