How to find the subscript of the first element of an array in php

Two implementation methods: 1. Use key() to get the subscript of the first element of the array, the syntax is "key (specified array)". 2. Use the "array_keys(original array)" statement to obtain all subscripts of the original array, return the key array containing all subscripts, and then use the "$key array name[0]" statement to obtain the first element of the key array value, which is the subscript of the first element of the original array.

The operating environment of this tutorial: Windows 7 system, PHP version 8.1, DELL G3 computer

php to find the array number Two methods for subscripting an element

Method 1: Use key() to obtain the subscript of the first element of the specified array

key () can return the key name of the current element in the array; initially, the current element points to the first element.

<?php
header("Content-type:text/html;charset=utf-8");
$arr=array("a"=>"1","b"=>"","c"=>"2","d"=>0,"e"=>"blue");
echo "原数组：";
var_dump($arr);
echo "数组第一个元素的下标为：".key($arr) ;
?>

Method 2: Use array_keys() and "key name array name [0]" to get the subscript of the first element of the specified array

• array_keys() function can obtain all subscripts of the original array and return a key array containing all subscripts

• Use "$ Key name array name [0]" Gets the first element of the key name array, which is the subscript of the first element of the original array

<?php
header("Content-type:text/html;charset=utf-8");
$arr=array("a"=>"1","b"=>"","c"=>"2","d"=>0,"e"=>"blue");
echo "原数组：";
var_dump($arr);
$keys=array_keys($arr);
echo "键名数组：";
var_dump($keys);
echo "原数组第一个元素的下标为：".$keys[0] ;
?>

Recommended learning: "PHP Video Tutorial"

The above is the detailed content of How to find the subscript of the first element of an array in php. For more information, please follow other related articles on the PHP Chinese website!