Example of using count to get the length of a multidimensional array in PHP

In the previous article, we introduced to you how to obtain the length of php array, but the array is divided into one-dimensional array, multidimensional array, then This article describes how to implement count to obtain the length of a multidimensional array in PHP. Share it with everyone for your reference. The specific analysis is as follows:

Let’s first take a look at the results of the following program:

$numb=array(             
array(10,15,30),array(10,15,30),array(10,15,30) 
);  
echo count($numb,1);

A.3
B.12
C.6
D.9
The answer is that if mode is set to COUNT_RECURSIVE (or 1) in the B
count function, the number of elements in the array in the multi-dimensional array will be recursively calculated (that is, 12 in your result). If mode is not set, it defaults to 0. Multidimensional arrays (arrays within arrays) are not detected (result 3).

The first thing to traverse is the outer arrayIt turns out that there are two elements ("color1", "color2", "color3") and then traverse ("color1" for 3
, "color2", "color3") The array results in 9 elements as 9
The result is 3+9=12

Reference example:

The code is as follows:

<?php
$fruits = array (
    array (1, 2,null,null, 5, 6),
    array (1, 2,null,null, 5, 6),
);
echo(count($fruits[0]));
?>

If you use an array defined in other ways, such as:
Copy the code as follows:

<?php
$fruits[0][0]=1;
$fruits[0][3]=1;
$fruits[0][4]=1;
echo(count($fruits[0]));
?>

In this way, 3 will be output, because arrays in PHP do not require indexing Continuous, the reference manual has the following paragraph:
Array:
PHP The array in is actually an ordered graph. A graph is a mapping of values ​​to keys type. This type is optimized in many ways, so you can use it as a real array, or a list (vector), a hash table (an implementation of a graph), a dictionary, a set, a stack, a queue, and more possibilities sex. It's also easy to simulate a tree since you can use another PHP array as a value.
Example:
Get the length of the first dimension of a two-dimensional or multi-dimensional array. This is a common program judgment. For example, the array you read is a two-dimensional array:

<?php
$arr=array(
 0=>array(&#39;title&#39; => &#39;新闻1&#39;, &#39;viewnum&#39; => 123, &#39;content&#39; => &#39;ZAQXSWedcrfv&#39;),
 1=>array(&#39;title&#39; => &#39;新闻2&#39;, &#39;viewnum&#39; => 99, &#39;content&#39; => &#39;QWERTYUIOPZXCVBNM&#39;)
);
?>

If you want to count the length of the array $arr, that is to say, the two-dimensional array has only two news, the number you want is also 2, but if you use count($arr) different versions of php, statistics The results are different;
Later I found in the php manual that the count function has a second parameter, which is explained as follows:
The count function has two parameters:
0( or COUNT_NORMAL) is the default and does not detect multi-dimensional arrays (arrays within arrays);
1 (or COUNT_RECURSIVE) is for detecting multi-dimensional arrays,
So if you want to determine whether the read array $arr has news information, just To write like this:

<?php
if(is_array($arr) && count($arr,COUNT_NORMAL)>0 )
{
  .....
} else {
  .....
}
?>

You can use code like this to test the function:

<?php
$arr=array(
 0=>array(&#39;title&#39; => &#39;新闻1&#39;, &#39;viewnum&#39; => 123, &#39;content&#39; => &#39;ZAQXSWedcrfv&#39;),
 1=>array(&#39;title&#39; => &#39;新闻2&#39;, &#39;viewnum&#39; => 99, &#39;content&#39; => &#39;QWERTYUIOPZXCVBNM&#39;)
);
echo &#39;不统计多维数组：&#39;.count($arr,0);//count($arr,COUNT_NORMAL)
echo "<br/>";
echo &#39;统计多维数组：&#39;.count($arr,1);//count($arr,COUNT_RECURSIVE)
?>

Summary:

This article has solved the problem of obtaining the first dimension length of a two-dimensional or multi-dimensional array in PHP. Is it very simple to obtain the length of a PHP array? I hope it will be helpful to you!

Related recommendations:

How to get the length of php array

Method to determine php array dimension (php array length)

php array, php array length_PHP tutorial

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