if语句中表达式的顺序 [英] The order of expressions in an if statement

问题描述

可能重复：

/ a Javascript缩小比较语句

我一直在编写 if 这样的语句：

Ive been writing my if statements like this:

if(variable1 === 1){}
if(variable2 > 10){}
if(variable3 == "a"){}

但我记得在某个地方读书（不幸的是我再也找不到那个页面了），如果语句最好这样写：

But I remember reading somewhere (unfortunately I cant find that page anymore), that if statements are better off written like this:

if(1 === variable1){}
if(10 < variable2){}
if("a" == variable3){}

你放的地方表达式右侧的变量。

Where you put the variable on the right hand side of the expression.

这是正确的吗？如果是这样，任何人都可以解释为什么这是正确的吗？此外，这适用于所有编程语言，还是只适用于javascript？

Is this correct? And, if so, can anyone shed any light on why this is correct? Also, does this apply to all programming languages, or just javascript?

TIA

推荐答案

1 === variable1 与用Yoda表示法编写的表达式 variable1 === 1 相同**：在左侧列出常数，在右侧列出变量。

1 === variable1 is same as the expression variable1 === 1 written in Yoda notation**: constant listed on left hand side, variable on the right hand side.

一些程序员选择使用它的主要原因是为了避免写入的常见错误 if（a = 1）程序员实际意味着 if（a == 1）或 if（a === 1）。以下代码行将起作用但不是预期的（ a 被分配一个值而如果块将始终被执行）：

The main reason why some programmers choose to use it is to avoid the common mistake of writing if (a = 1) where the programmer actually meant if (a == 1) or if (a === 1). The following line of code will work but not as expected (a is assigned a value and if block will always get executed):

if (a = 1) {}

反过来写的相同表达式将生成语法（或编译）错误：

The same expression written the other way round will generate a syntax (or compile) error:

if (1 = a) {}

程序员可以立即发现错误并且修复它。

The programmer can immediately spot the error and fix it.

我不喜欢或使用尤达符号。编码时我试着睁大眼睛。

I do not like or use the Yoda notation. I try to keep my eyes open while coding.

**我无法找到这个词的来源。

** I am unable to find out the origin of this term.

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