将默认值分配给变量的最短方法？ [英] Shortest way to assign a default value to a variable?

问题描述

我现在有权使用cookie值（如果存在），否则使用默认值：

I have this right now to use a cookie value if exists otherwise use a default value:

$default_carat_min = "0.25";
if($_COOKIE["diamond-search_caratMin"])
{
    $default_carat_min = $_COOKIE["diamond-search_caratMin"];
}

我将不得不使用很多变量，会变得非常混乱/丑陋。因此，我尝试提出一种更简洁的书写方式。

I am going to have to do this with a lot of variables, and its going to get really cluttered/ugly. So I am trying to come up with a cleaner way of writing this.

我尝试过：

$default_carat_min = $_COOKIE["diamond-search_caratMin"] | "0.25";

哪个没有用。

I可以这样做：

$default_carat_min = $_COOKIE["diamond-search_caratMin"] ? $_COOKIE["diamond-search_caratMin"] : "0.25";

但是我不喜欢重复 $ _ COOKIE 两次。我想知道是否可以像第二个示例那样编写它？

But I don't like how I have to repeat the $_COOKIE twice. I am wondering if there is a way to write it something like my 2nd example?

推荐答案

PHP 5.3为< a href = http://www.php.net/manual/zh-CN/language.operators.comparison.php#language.operators.comparison.ternary rel = noreferrer>三元运算符：

$default_carat_min = $_COOKIE["diamond-search_caratMin"] ?: "0.25";

如果左侧为true，则向左侧求值，否则为右侧。

Which evaluates to the left side if the left side is true, and evaluates to the right side otherwise.

在5.3之前，您必须使用长格式。

Prior to 5.3, however, you'd have to use the long form.

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