我在哪里可以阅读到有关用“?"完成的条件的信息?和“:" (冒号)? [英] Where can I read about conditionals done with "?" and ":" (colon)?

问题描述

可能重复:
参考-此符号在PHP中是什么意思?

Possible Duplicate:
Reference - What does this symbol mean in PHP?

我一直在用if/else或一年左右来做条件.查看一些新代码，我看到一个条件条件似乎在使用?和:而不是if和else.我想了解更多有关此的内容，但是我不确定要从Google那里找到解释其工作原理的文章.我该怎么办?

I've been doing conditionals with if/else or a year or so now. Looking at some new code, I'm seeing a conditional that appears to use ? and : instead of if and else. I'd like to learn more about this, but I am not sure what to google to find articles explaining how it works. How can I do it?

推荐答案

它是三元运算符.

基本用法类似

$foo = (if this expressions returns true) ? (assign this value to $foo) : (otherwise, assign this value to $foo)

它不仅可以用于分配，还可以像其他示例那样在下面出现.

It can be used for more than assignment though, it looks like other examples are cropping up below.

我认为您在许多现代的OO风格的PHP中看到此问题的原因是，如果没有静态类型，您最终将对任何特定变量的类型抱有偏执，并且一元三进制的混乱程度要小于7.如果有条件则行.

I think the reason you see this in a lot of modern, OO style PHP is that without static typing you end up needing to be paranoid about the types in any particular variable, and a one line ternary is less cluttered than a 7 line if/else conditional.

此外，为了尊重命名中的评论和真实性，请阅读有关 the 计算机科学中的三元运算符 s .

Also, in deference to the comments and truth in naming, read all about the ternary operators in computer science.

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