How to find the length of a two-dimensional array in php

In PHP, you can use the count() function to find the length of a two-dimensional array. This function can count the number of all elements in the array, which is the length of the array; when the second parameter of the function Set to "COUNT_RECURSIVE" or 1 to recursively calculate the number of elements in the array, that is, to find the length of the two-dimensional array. The syntax is "count(two-dimensional array, COUNT_NORMAL)" or "count(two-dimensional array, 1 )".

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

In PHP, you can use count () function to find the length of a two-dimensional array.

We all know that the array length of a one-dimensional array can be found using the count() function. In fact, the length of a two-dimensional array can also be found using the count() function.

Only need to pass two parameters to the count() function: the first parameter is $array, specifying the array to be counted; and the second parameter is $mode, the value is set to COUNT_RECURSIVE or 1, so that the count() function will recursively calculate the number of elements in the array, which is especially useful for calculating the number of elements in multi-dimensional arrays.

Example: length of two-dimensional array

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

After reading the above output, are you confused? There are not only 5 elements in the array ("张三", 25, "高书", "PHP tutorial", "English") , why does the array length displayed in the result not be 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 ("高书", "PHP Tutorial", "English") will be counted again. , so the final result is 6.

Note:

PHP provides us with two functions to calculate the length of the array, namely count() and sizeof() functions; but sizeof() function It 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.

Count() function syntax:

count($array [, $mode = COUNT_NORMAL])

• $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 will return 0.

Recommended learning: "PHP Video Tutorial"

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