php索引项 [英] php index of item
问题描述
我有一个如下所示的数组:
I have an array that looks like this:
$fruit = array('apple','orange','grape');
如何在上面的数组中找到特定项目的索引? (例如,值'orange')
How can I find the index of a specific item, in the above array? (For example, the value 'orange')
推荐答案
尝试 array_search 函数。
从手册中的第一个示例:
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;
?>
提醒
比较结果时,请务必使用 ==显式测试值
运算符。 false
=
When comparing the result, make sure to test explicitly for the value false
using the ===
operator.
因为PHP中的数组是基于0的,如果您要搜索的元素是数组中的第一个元素,则返回值0。
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.
虽然0是有效结果,但它也是一个假值,意味着以下将失败:
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');
}
?>
这是因为 ==
运算符检查for equality (通过type-juggling),而 ===
运算符检查 identity 。
This is because the ==
operator checks for equality (by type-juggling), while the ===
operator checks for identity.
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