How to use php array function

As a revolutionary web development language, PHP has many powerful features and functions, among which array functions are one of them. Arrays are one of the most common data types in PHP and are widely used in various web applications.

In this article, we will introduce some PHP array functions and their application in actual development. We will divide the function into the following parts according to its purpose: array sorting function, array processing function, array query function, and array merging function.

1. Array sorting function

1. sort()
   sort() function is used to sort the array in ascending order, that is, sort from small to large. The sample code is as follows:

$numbers = array(5, 3, 8, 1);
sort($numbers);
print_r($numbers);

The output result is: Array([0] => 1,[1] => 3,[2] => 5,[3] => 8)

2. rsort()
   rsort() function is used to sort the array in descending order, that is, from large to small. The sample code is as follows:

$numbers = array(5, 3, 8, 1);
rsort($numbers);
print_r($numbers);

The output result is: Array([0] => 8,[1] => 5,[2] => 3,[3] => 1)

3. asort()
   asort() function is used to sort the array in ascending order and retain the original key-value relationship. The sample code is as follows:

$numbers = array("A"=>5, "B"=>3, "C"=>8, "D"=>1);
asort($numbers);
print_r($numbers);

The output result is: Array([D] => 1,[B] => 3,[A] => 5,[C] => 8)

4. arsort()
   arsort() function is used to sort the array in descending order and retain the original key-value relationship. The sample code is as follows:

$numbers = array("A"=>5, "B"=>3, "C"=>8, "D"=>1);
arsort($numbers);
print_r($numbers);

The output result is: Array([C] => 8,[A] => 5,[B] => 3,[D] => 1)

2. Array processing function

1. array_push()
   array_push() function is used to add one or more elements to the end of the array. The sample code is as follows:

$colors = array("red", "green");
array_push($colors, "blue", "yellow");
print_r($colors);

The output result is: Array([0] => red,[1] => green,[2] => blue,[3] => yellow)

2. array_pop()
   array_pop() function is used to delete an element from the end of the array. The sample code is as follows:

$colors = array("red", "green", "blue");
$lastColor = array_pop($colors);
print_r($colors);
echo $lastColor;

The output result is: Array([0] => red,[1] => green)
blue

3. array_shift ()
   array_shift() function is used to delete an element from the head of the array. The sample code is as follows:

$colors = array("red", "green", "blue");
$firstColor = array_shift($colors);
print_r($colors);
echo $firstColor;

The output result is: Array([0] => green,[1] => blue)
red

4. array_unshift ()
   array_unshift() function is used to add one or more elements to the head of the array. The sample code is as follows:

$colors = array("red", "green");
array_unshift($colors, "blue", "yellow");
print_r($colors);

The output result is: Array([0] => blue,[1] => yellow,[2] => red,[3] => green)

3. Array query function

1. in_array()
   in_array() function is used to find whether the specified element is contained in the array. If found, it returns true, otherwise it returns false. The sample code is as follows:

$colors = array("red", "green", "blue");
if (in_array("green", $colors)) {
    echo "找到了";
} else {
    echo "没找到";
}

The output result is: found

2. array_search()
   array_search() function is used to find an element in the array and return Its corresponding key value. The sample code is as follows:

$colors = array("red", "green", "blue");
$pos = array_search("green", $colors);
echo $pos;

The output result is: 1

3. array_key_exists()
   array_key_exists() function is used to determine whether the specified key exists in the array. Returns true if present, false otherwise. The sample code is as follows:

$colors = array("red", "green", "blue");
if (array_key_exists(1, $colors)) {
    echo "存在";
} else {
    echo "不存在";
}

The output result is: exists

4. Array merge function

1. array_merge()
   array_merge() function Used to combine two or more arrays into one array. The sample code is as follows:

$colors1 = array("red", "green");
$colors2 = array("blue", "yellow");
$colors = array_merge($colors1, $colors2);
print_r($colors);

The output result is: Array([0] => red,[1] => green,[2] => blue,[3] => yellow)

2. array_combine()
   array_combine() function is used to combine the keys and values ​​of an array into an associative array. The sample code is as follows:

$keys = array("A", "B", "C");
$values = array("red", "green", "blue");
$colors = array_combine($keys, $values);
print_r($colors);

The output result is: Array([A] => red,[B] => green,[C] => blue)

As can be seen from the above example, the array functions provided by PHP are very convenient and can help us quickly implement various array operations. In actual development, we should make full use of these functions to improve development efficiency and code quality.

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