How to determine whether an array is a two-dimensional array in PHP

Two judgment methods: 1. Use the count() function to compare whether the length obtained is the same when the second parameter is omitted and when the second parameter is not omitted. The syntax "count($arr)!=count( $arr,1)", if the return value is true, it is a two-dimensional array, and vice versa. 2. Use the foreach statement to loop through the array, and use is_array() in the loop body to determine whether the element value is an array type. If neither element is of array type, it is not a two-dimensional array. If one is, it is a two-dimensional array.

The operating environment of this tutorial: windows7 system, PHP version 8.1, DELL G3 computer

php determines whether the array is Two methods for two-dimensional arrays

Method 1: Use the count() function to determine

The count() function calculates the number in the array The number of units or the number of attributes in the object

count ( mixed $var [, int $mode ] )

$mode: is an optional parameter and can be omitted.

• If the $mode parameter is omitted, or set to COUNT_NORMAL or 0, the count() function will not detect multidimensional arrays;

• If If $mode is set to COUNT_RECURSIVE or 1, the count() function will recursively count the number of elements in the array, which is especially useful for calculating the number of elements in multi-dimensional arrays.

If the $mode parameter is omitted, count will not detect multi-dimensional arrays and will only obtain the number of elements in one dimension.

So you only need to compare whether the length obtained when the $mode parameter is omitted and when the $mode parameter is not omitted is the same to determine whether it is a two-dimensional array.

count($arr) != count($arr, 1)

• If they are not equal (the return value is true), it is a two-dimensional array
  

• If they are equal (the return value is false) ), it is not a two-dimensional array
  

<?php
header(&#39;content-type:text/html;charset=utf-8&#39;);   
$arr = array(1,array(2,4),6); 
var_dump($arr);
if (count($arr) != count($arr, 1)) {
    echo &#39;是二维数组&#39;;
} else {
    echo &#39;不是二维数组&#39;;
} 
?>

Method 2: foreach statement is_array() function

• Use the foreach statement to loop through the array

• In the loop body, use the is_array() function to determine whether the element value is an array type, if not, then it is not Two-dimensional array, if there is one, it is a two-dimensional array

<?php  
header("content-type:text/html;charset=utf-8");
$arr = array(1,2,3,4,5); 
var_dump($arr);
$con=0;
foreach($arr as $v){
	if(is_array($v)){
		$con=1;
		break;
	}else{
		$con=0;
	}
}
if($con==1){
	echo "是二维数组";
}else{
	echo "不是二维数组";
}

?>

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