How to determine how many values ​​there are in an array in php

In PHP, you can use the count() or sizeof() function to determine how many values ​​there are in the array. Both the count() and sizeof() functions can count the number of elements in the array, and sizeof() is an alias of the count() function. The usage is consistent, the syntax is "count($arr,$m)"; the second The parameter is used to process multi-dimensional arrays and can be omitted. If the value is set to 1 or "COUNT_RECURSIVE", the number of elements of the multi-dimensional array can be calculated.

The operating environment of this tutorial: windows7 system, PHP8 version, DELL G3 computer

The number of values ​​​​in the array is determined in php, which is the statistical array The number of elements in is the length of the array.

PHP provides us with two functions to calculate the length of an array, namely the count() and sizeof() 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: The number of elements in a one-dimensional array

<?php 
header("content-type:text/html;charset=utf-8");
$arr=array(1,2,3,4,5,6,7,8,9);
var_dump($arr);
echo "数组中有 ".count($arr)."个值";
?>

Example 2: The number of elements in 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 "数组中有 ".count($arr,1)."个值";
?>

After reading the above output, are you confused? There are not only 5 elements in the array ("Zhang San", 25, "High Number", "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, and "array("高数","PHP tutorial","English")" will be regarded as an overall statistics Once, the elements in it ("Advanced Mathematics", "PHP Tutorial", "English") will be counted again, so the final result is 6.

Recommended learning: "PHP Video Tutorial"

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