This chapter describes several common PHP array internals. We’ve already looked at PHP arrays, creating 1 array with the array() function and removing 1 array element with the unset() function. In this section we will also learn about some other common internal functions related to arrays. count,sizeof count - Returns the number of elements in an array. sizeof, an alias for count, functions like count 1 and returns the number of elements in an array. An example of the count function is shown below, where the number of elements in the output array is 6.
<?php
$a = array(1,2,4,5,3,9);
echo count($a); //6
?>sort sort - Sorts the elements of an array. After sorting, the original key of each element of the array is changed. Examples of sort functions are as follows:
<html>
<body>
<?php
$a = array(1,2,4,5,3,9);
echo "before sorting: <br />";
foreach ($a as $key=>$value)
{
echo "a[$key]: $value <br />";
}
sort($a);
echo "after sorting: <br />";
foreach ($a as $key=>$value)
{
echo "a[$key]: $value <br />";
}
?>
</body>
</html>The display results returned are:
before sorting:
a[0]: 1
a[1]: 2
a[2]: 4
a[3]: 5
a[4]: 3
a[5]: 9
after sorting:
a[0]: 1
a[1]: 2
a[2]: 3
a[3]: 4
a[4]: 5
a[5]: 9asort asort - Sort the elements of the array, leaving each element as key. We changed sort($a) in the above example to asort($a) and got the following result:
before sorting:
a[0]: 1
a[1]: 2
a[2]: 4
a[3]: 5
a[4]: 3
a[5]: 9
after sorting:
a[0]: 1
a[1]: 2
a[4]: 3
a[2]: 4
a[3]: 5
a[5]: 9ksort ksort - Sorts each element of the array according to the size of key. Examples of ksort functions are as follows:
<html>
<body>
<?php
$fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");
ksort($fruits);
foreach ($fruits as $key => $val) {
echo "$key : $val <br />";
}
?>
</body>
</html>The results returned are as follows:
a : orange
b : banana
c : apple
d : lemon