为什么python不允许在函数和变量名中使用连字符? [英] Why does python disallow usage of hyphens within function and variable names?

问题描述

我一直想知道为什么我们不能在python中的函数名和变量名之间使用连字符

I have always wondered why can't we use hyphens in between function names and variable names in python

尝试过函数式编程语言，如 Lisp 和 Clojure，其中允许使用连字符.为什么python不这样做.

Having tried functional programming languages like Lisp and Clojure, where hyphens are allowed. Why python doesn't do that.

# This won't work -- SyntaxError
def is-even(num):
    return num % 2

# This will work
def is_even(num):
    return num % 2

我确信 Guido 爵士一定是出于某些原因这样做了.我用谷歌搜索但无法找到答案.任何人都可以对此有所了解吗?

I am sure Sir Guido must have done this because of some reasons. I googled but couldn't manage to find the answer. Can anyone please throw some light on this?

推荐答案

因为连字符用作减法运算符.想象一下，你可以有一个 is-even 函数，然后你有这样的代码:

Because hyphen is used as the subtraction operator. Imagine that you could have an is-even function, and then you had code like this:

my_var = is-even(another_var)

is-even(another_var) 是对函数is-even 的调用，还是减去函数even 的结果来自名为 is?

Is is-even(another_var) a call to the function is-even, or is it subtracting the result of the function even from a variable named is?

Lisp 方言没有这个问题，因为它们使用前缀表示法.例如，

Lisp dialects don't have this problem, since they use prefix notation. For example, there's clear difference between

(is-even 4)

和

(- is (even 4))

在 Lisps 中.

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