项目的php索引 [英] php index of item

问题描述

我有一个看起来像这样的数组:

$fruit = array('apple','orange','grape');

如何在上述数组中找到特定项目的索引?(例如，值 'orange')

解决方案

试试 array_search 功能.

来自手册中的第一个示例:

<块引用>

 '蓝色', 1 => '红色', 2 => '绿色', 3 => '红色');$key = array_search('green', $array);//$key = 2;$key = array_search('red', $array);//$key = 1;?>

注意事项

比较结果时，请确保使用 === 运算符显式测试值 false.

由于 PHP 中的数组是从 0 开始的，如果您要搜索的元素是数组中的第一个元素，则将返回值 0.

虽然 0 是一个有效的结果，但它也是一个假值，意味着以下将失败:

 '蓝色', 1 => '红色', 2 => '绿色', 3 => '红色');$key = array_search('blue',$array);if($key == false) {throw new Exception('找不到元素');}?>

这是因为 == 运算符检查 相等(通过类型杂耍)，而 === 运算符检查 身份.

I have an array that looks like this:

$fruit = array('apple','orange','grape');

How can I find the index of a specific item, in the above array? (For example, the value 'orange')

解决方案

Try the array_search function.

From the first example in the manual:

<?php
$array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');

$key = array_search('green', $array); // $key = 2;
$key = array_search('red', $array);   // $key = 1;
?>

A word of caution

When comparing the result, make sure to test explicitly for the value false using the === operator.

Because arrays in PHP are 0-based, if the element you're searching for is the first element in the array, a value of 0 will be returned.

While 0 is a valid result, it's also a falsy value, meaning the following will fail:

<?php
    $array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');   

    $key = array_search('blue',$array);

    if($key == false) {
        throw new Exception('Element not found');
    }
?>

This is because the == operator checks for equality (by type-juggling), while the === operator checks for identity.

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