How to find the number of elements in a two-dimensional array in PHP

In PHP, you can use the count() or sizeof() function to find out how many elements there are in a two-dimensional array; both functions can count the number of elements in a two-dimensional array, the syntax "count($ arr,$m)" or "sizeof($arr,$m)", you only need to set the value of parameter "$m" to "1" or "COUNT_RECURSIVE" to recursively calculate the number of elements in the array.

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

Find how many elements there are in the two-dimensional array, that is Calculate the length of a two-dimensional array. PHP provides us with two functions to calculate the length of an array, namely the count() and sizeof() functions; both of these functions can handle multidimensional functions.

Note: The sizeof() function is an alias of the count() function, that is, the function and usage of the sizeof() function are exactly the same as the count() function.

The following will focus on the count() function.

The count() function can count the number of all elements in the array, or the number of attributes in the object. Its syntax format is as follows:

count($array , $mode )

The parameter description is as follows:

• $array: is the array or object to be counted;
• $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 $mode is set to COUNT_RECURSIVE or 1, the count() function Will recursively count the number of elements in the array, especially useful for counting the number of elements in multi-dimensional arrays.

Tip: If $array is neither an array nor an object, the count() function will return 1; if $array is equal to NULL, the count() function Return 0.

Example 1: count() function calculates the length of a two-dimensional array

<?php
header("Content-type:text/html;charset=utf-8");
$arr= array(
	"张三",
	25,
    array("高数","PHP教程","英语"),
);
//输出语句
var_dump($arr);
echo "二维数组的长度为：".count($arr,1);
?>

Looked at the above output results , are you confused? There are not only 5 elements in the array ("张三", 25, "高书", "PHP Tutorial ", "English"), why is the array length displayed in the result not 5, but 6?

In fact, this is because at this time, the count() function loops to count all elements in the two-dimensional array, "array("高num","PHP Tutorial","English")" It will be counted once as a whole, and the elements inside it ("高码", "PHP tutorial", "English") will be counted again. , so the final result is 6.

Example 2: Use the sizeof() function to calculate the length of a two-dimensional array

<?php
header("Content-type:text/html;charset=utf-8");
$arr = [&#39;php中文网&#39;,&#39;PHP教程&#39;,[&#39;https://www.php.cn/&#39;,&#39;sizeof()函数&#39;,&#39;数组长度&#39;]];
//输出语句
var_dump($arr);
echo "二维数组的长度为：".sizeof($arr, 1);
?>

Recommended learning: "PHP Video Tutorial》

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