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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] ; ?>
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