How to get the length of an array in php (with examples)

How to get the length of an array in php (with examples)_PHP tutorial

WBOY

Release： 2016-07-13 10:25:52

Original

856 people have browsed it

It is very simple to get the length of an array in PHP. PHP provides us with two functions to calculate the length of a one-dimensional array, such as count and sizeof, which can directly count the length of the array. Let's take a look at a few examples.
How to get the length of an array in php, use the php function count(), or sizeof()
For example:

Copy the code The code is as follows:

$arr = Array('0','1','2','3','4');
echo count($arr);
// Output 5
$arr = array('A','B','C');
echo sizeof($arr);
//Output 3

sizeof () and count() have the same purpose. Both functions can return the number of array elements. You can get the number of elements in a regular scalar variable. If the array passed to this function is an empty array, or a If there is no set variable, the number of array elements returned is 0;
The two functions have the same function. According to the manual, sizeof() is an alias of the function count().

So how to count the length of multi-dimensional arrays? Continue to look at the example
For example, the array you read is a two-dimensional array:

Copy the code The code is as follows:

$arr=array(
                        0=>array('title' => 'News 1', 'viewnum' => 123, 'content' => ' ZAQXSWedcrfv'),
          1=>array('title' => 'News2', 'viewnum' => 99, 'content' => 'QWERTYUIOPZXCVBNM')
          );
?>

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 have different statistical results;
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 contains news information, just To write like this:

Copy code The code is as follows:

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

You can use code like this to test the function:

Copy the code The code is as follows:

$arr=array(
array ),
1=>array('title' => 'News2', 'viewnum' => 99, 'content' => 'QWERTYUIOPZXCVBNM')
echo 'Do not count multi-dimensional arrays:'.count($arr,0);//count($arr,COUNT_NORMAL)

echo "
";
echo 'Count multi-dimensional arrays ：'.count($arr,1);//count($arr,COUNT_RECURSIVE)
?>