- Counting elements of an array.
- Counting elements of a multidimensional or nested array.
- Count the frequency of unique values in an array.
- Finding the maximum and minimum values in an array.
Counting elements in arrays
//Count function syntax count(Countable|array $value, int $mode = COUNT_NORMAL): int
The count( ) function returns the number of elements in the array, the following example prints 7 as expected:
<?php
$days = array("Mon", "Tue", "Wed", "Thu",
"Fri", "Sat", "Sun");
echo count($days); // 7
The count( ) function works on an array or countable object and returns 0 when either an empty array or a variable that isn’t set is examined. If there is any doubt, isset( ) and is_array( ) should be used to check the variable being considered.
Counting elements of a multidimensional or nested array
To find the number of elements in a multidimensional or nested array, the count() function has an optional mode argument COUNT_RECURSIVE that recursively counts the elements:
<?php
//7 elements
$a = array('sun','mon','tue','wed',
'thu','fri','sat');
//12 elements
$b = array('jan','feb','mar','apr',
'may','jun','jul','aug',
'sep','oct','nov','dec');
//2 elements
$c = array ('days' => $a, 'month' => $b);
echo count ($c); //2
echo count ($c, COUNT_RECURSIVE); //21
//or
echo count ($c, 1); //21
sizeof vs. count
The sizeof() function is an alias for the count() function.
<?php
$days = array("Mon", "Tue", "Wed", "Thu",
"Fri", "Sat", "Sun");
echo sizeof($days); // 7
Count frequency of unique values in an array
//Syntax array_count_values(array $array): array
The array_count_values() function counts how many times a unique value is found in an array. It returns an associative array with the keys representing the unique element of the array, and the value containing the number of times that unique element occurred within the array.
<?php
$a = array(1, 3, 1, 5, 5, 9, 0, 5);
$b = array_count_values( $a );
$c = print_r ( $b , true);
echo "<pre> $c </pre>";
/*Prints:
Array
(
[1] => 2
[3] => 1
[5] => 3
[9] => 1
[0] => 1
)*/
This example counts the frequency of the values in the array. The array_count_values function returns an array that uses the value as an index and the frequency as the value.
Finding the maximum and minimum values in an array
The maximum and minimum values can be found from an array numbers with max( ) and min( ), respectively:
//max functin syntax max(array $value_array): mixed //min function syntax min(array $value_array): mixed
If an array of integers is examined, the returned result is an integer, if an array of floats is examined, min( ) and max( ) return a float:
<?php $var = array(10, 5, 37, 42, 1, -56); echo max($var); // prints 42 echo min($var); // prints -56
Both min( ) and max( ) can also be called with a list of integer or float arguments:
<?php echo max (10, 5, 37, 42, 1, -56); // prints 42 echo min (10, 5, 37, 42, 1, -56); // prints -56
Both max( ) and min( ) work with strings or arrays of strings, but the results may not always be as expected.
Working with arrays:
