php array function method

PHP is a popular programming language used for developing web applications and dynamic websites. In PHP, an array is a common data type, a data structure consisting of a set of values. PHP provides many functions and methods to process arrays, allowing developers to easily sort, filter, search, etc. arrays.

This article will introduce the commonly used array function methods in PHP.

1. Method of creating array

1. array()
   array() function is the most basic method of creating an array. It takes any number of values ​​as arguments and creates a new array using them as array elements.

Example:

$arr ​​= array('apple', 'orange', 'banana');

2. []Operator## The #[] operator is a new way to create arrays introduced in PHP 5.4. It can create an array directly without calling the array() function, making it more concise to use.
   

Example:

$arr ​​= ['apple', 'orange', 'banana'];

range()
3. range The () function is a method to create an array according to specified rules. It receives three parameters: a start value, an end value, and an optional step value. It creates an array containing all integer values ​​in the specified range.
   

Example:

$arr ​​= range(1, 10);

2. Array operation method

array_push()
1. The array_push() function is used to add one or more elements to the end of the array.
   

Example:

$arr ​​= array('apple', 'orange');

array_push($arr, 'banana', 'grape');

array_pop()
2. array_pop() function is used to delete an element from the end of the array.
   

Example:

$arr ​​= array('apple', 'orange', 'banana');

array_pop($arr);

array_shift()
3. array_shift() function is used to delete an element from the beginning of the array.
   

Example:

$arr ​​= array('apple', 'orange', 'banana');

array_shift($arr);

array_unshift()
4. array_unshift() function is used to insert one or more elements at the beginning of the array.
   

Example:

$arr ​​= array('banana');

array_unshift($arr, 'apple', 'orange');

array_reverse()
5. array_reverse() function is used to reverse the order of elements in an array.
   

Example:

$arr ​​= array('apple', 'orange', 'banana');

$arr ​​= array_reverse($arr);

3. Array traversal method

foreach()
1. The foreach() function is used to traverse all elements in the array and assign them to a variable. It is the most commonly used method of traversing arrays in PHP.
   

Example:

$arr ​​= array('apple', 'orange', 'banana');

foreach($arr as $value){
echo $value . '\n';
}

for()
2. thefor() function can also be used to iterate over the array, but it requires manual counting in the loop to access the array elements in .
   

Example:

$arr ​​= array('apple', 'orange', 'banana');

for($i = 0; $i < count ($arr); $i ){
echo $arr[$i] . '\n';
}

4. Array sorting method

sort ()
1. sort() function is used to sort the elements in the array in ascending order.
   

Example:

$arr ​​= array('apple', 'orange', 'banana');

sort($arr);

rsort()
2. rsort() function is used to sort the elements in the array in descending order.
   

Example:

$arr ​​= array('apple', 'orange', 'banana');

rsort($arr);

asort()
3. asort() function sorts the elements in the array according to their values ​​and preserves the key-value association.
   

Example:

$arr ​​= array('apple' => 3, 'orange' => 2, 'banana' => 1);

asort($arr);

ksort()
4. ksort() function sorts the elements in an array according to their keys and preserves the key-value association.
   

Example:

$arr ​​= array('apple' => 3, 'orange' => 2, 'banana' => 1);

ksort($arr);

5. Array filtering method

array_filter()
1. array_filter() function is used to filter elements from an array. It accepts two parameters: the array to be filtered and the callback function. The callback function can be customized to define filtering rules.
   

Example:

$arr ​​= array('apple', 'orange', 'banana');

$newArr = array_filter($arr, function($value ){
return $value != 'banana';
});

array_map()
2. array_map() function is used to apply an Callback function and returns a new array.
   

Example:

$arr ​​= array('apple', 'orange', 'banana');

$newArr = array_map(function($value){
return strtoupper($value);
}, $arr);

6. Array search method

in_array()
1. in_array() function is used Searches the array for the specified value and returns true if found, false otherwise.
   

Example:

$arr ​​= array('apple', 'orange', 'banana');

if(in_array('banana', $arr)) {
echo 'Found';
}else{
echo 'Not Found';
}

array_search()
2. array_search() function is used in Searches an array for a specified value and returns its key.
   

Example:

$arr ​​= array('apple', 'orange', 'banana');

$key = array_search('banana', $arr) ;

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