PHPでの並べ替え
- WBOYオリジナル
- 2024-08-29 13:04:46406ブラウズ
並べ替えとは、配列の要素を特定の順序で並べることです。 PHP は、数値配列などの通常の配列と連想配列に対してソートを実行します。数値配列のような通常の配列は、単純な sort() 関数を使用して並べ替えることができます。また、連想配列で並べ替えを実行するには、さまざまな関数があります。
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並べ替えは、昇順または降順、アルファベット順または数値順、自然な方法、ランダムな順序、およびユーザー定義の順序で行うことができます。数値配列やインデックス付き配列などの配列、および連想配列の場合、並べ替えはキーに基づいて、または昇順または降順などの 2 つの順序のいずれかの値に基づいて昇順または降順配列で行われます。データ要素がソートされた形式である場合、配列でソートすると検索が容易になります。
PHP では並べ替えはどのように実行されますか?
並べ替えは、PHP でsort関数を使用して実行されます。さまざまなソート関数があります。
年功序列に基づいて家族のメンバーの年齢を知りたいとします。家族には 15 人のメンバーがいる場合もあります。 15 人のメンバーの年齢を並べ替えるには、sort 関数を使用し、結果をすぐに取得します。したがって、このような場合には、sort が登場し、推奨されます。
また、ライブラリを使用する必要はありません。
構文:
sort(array);
ここで、配列は入力配列の名前です。
次の例では、$people 配列と $ages 配列の要素を並べ替えます。
アルファベット順に並べ替えます:
$people = array ('Rama', 'James', 'Mary', 'Alice', 'Radha');
数値順に並べ替えます:
$ages = array (25,10,30,15,20);
上記の 2 つの配列を結合し、1 つの連想配列を作成します。
$people_ages = array ('James' => 25, 'Rama' => 10, 'Mary' => 30, 'Alice' => 15, 'Radha' => 20);
例:
を使用して数値順に並べ替えます。コード:
<?php
//example to perform ages array
$ages = array(25,10,30,15,20);
// calculate length of array
$array_length = count($ages);
echo "Before Sort"."<br>";
//array before sorting
for($i=0;$i<$array_length;$i++)
{
echo $ages[$i] ."<br>";
}
echo '<hr>';
//performing sort
sort($ages);
echo "After Sort"."<br>";
//array after sorting
for($i=0;$i<$array_length;$i++)
{
echo $ages[$i]."<br>";
} ?>
出力:
例:
を使用してアルファベット順に並べ替えます。コード:
<?php
//example to perform people array
$people= array('Rama', 'James', 'Mary', 'Alice', 'Radha');
// calculate length of array
$array_length = count($people);
echo "Before Sort"."<br>";
//array before sorting
for($i=0;$i<$array_length;$i++)
{
echo $people[$i] ."<br>";
}
echo '<hr>';
//performing sort
sort($people);
echo "After Sort"."<br>";
//array after sorting
for($i=0;$i<$array_length;$i++)
{
echo $people[$i]."<br>";
}
?>
出力 :
連想配列の並べ替え
キーと値のペアが関連付けられている連想配列に対して並べ替えを実行すると、キーが失われます。また、並べ替えは実行されますが、配列の各要素には新しい数値インデックスが割り当てられています。
コード:
// example to perform sort on people and ages array together
// you will find that the keys are not preserved and changed
$people_ages = array('James' => 25, 'Rama' => 10, 'Mary' => 30, 'Alice' => 15, 'Radha' => 20);
// calculate length of array
$array_length = count($people_ages);
echo "Before Sort"."<br>";
//array before sorting we will use foreach loop
foreach($people_ages as $key=>$value)
{
echo $key."=>".$value."<br>";
}
echo '<hr>';
//performing sort
sort($people_ages);
echo "After Sort"."<br>";
//array after sorting
foreach ($people_ages as $key=>$value)
{
echo $key."=>".$value."<br>";
}
出力:
したがって、単純な sort() の代わりに、asort() を使用します。 asort() は、連想配列の要素を昇順にソートする関数です。 arsort() は、配列の要素を降順に並べ替える関数です。どちらも値によってソートされます。ここで、これらの配列と他の配列関数について詳しく学びましょう
PHP での並べ替えの種類
さまざまな種類の配列関数を以下に示し、並べ替えの順序 (昇順か降順か) とキーによる並べ替えまたは値による並べ替え関数についても説明します。
- sort(): this function sorts the input array in ascending order and sorts it by value
- rsort(): this function sorts the input array in descending order and sorts it by value
- asort(): this function sorts the input array in ascending order and sorts it by value
- arsort(): this function sorts the input array in descending order and sorts by value
- ksort(): this function sorts the input array in ascending order and sorts it by key
- krsort(): this function sorts the input array in descending order and sorts it by key
- usort(): this function sorts the input array based on the user-defined function and sorts by value
- uasort(): this function sorts the input array based on the user-defined function and sorts by value
- uksort(): this function sorts the input array based on the user-defined function and sorts by key
- natsort(): this function sorts the input array-based natural ordering.
- natcasesort(): this function sorts the input array-based natural ordering and is case insensitive.
- shuffle(): this function sorts the input array based on the value, and the output is a random order of values.
Let us learn about each function in detail
1. sort()
This function we have already seen. This function performs sorting on the given array and arranges the elements of the array in ascending array.
Code :
//example to perform ages array
$ages = array(25,10,30,15,20);
// calculate length of array
$array_length = count($ages);
echo "Before Sort"."<br>";
//array before sorting
for($i=0;$i<$array_length;$i++)
{
echo $ages[$i] ."<br>";
}
echo '<hr>';
//performing sort
sort($ages);
echo "After Sort"."<br>";
//array after sorting
for($i=0;$i<$array_length;$i++)
{
echo $ages[$i]."<br>";
}
Output:
2. rsort()
This function performs sorting on the given array and arranges the elements of the array in descending array, opposite of what sort() function does. Also, the sorting is performed with values.
a. Code:
//example to perform ages array
$ages = array(25,10,30,15,20);
// calculate length of array
$array_length = count($ages);
echo "Before Sort"."<br>";
//array before sorting
for($i=0;$i<$array_length;$i++)
{
echo $ages[$i] ."<br>";
}
echo '<hr>';
//performing sort
rsort($ages);
echo "After Sort"."<br>";
//array after sorting
for($i=0;$i<$array_length;$i++)
{
echo $ages[$i]."<br>";
}
Output :
b. Code:
//example to perform people array
$people= array('Rama', 'James', 'Mary', 'Alice', 'Radha');
// calculate length of array
$array_length = count($people);
echo "Before Sort"."<br>";
//array before sorting
for($i=0;$i<$array_length;$i++)
{
echo $people[$i] ."<br>";
}
echo '<hr>';
//performing sort
rsort($people);
echo "After Sort"."<br>";
//array after sorting
for($i=0;$i<$array_length;$i++)
{
echo $people[$i]."<br>";
}
Output:
3. asort()
This function performs sorting on the given array and arranges the array’s values in ascending order, opposite of what sort() function does. Also, the sorting is performed with values and not keys.
Code :
//example to perform people_ages array
$people_ages = array('James' => 25, 'Rama' => 10, 'Mary' => 30, 'Alice' => 15, 'Radha' => 20);
// calculate length of array
$array_length = count($people_ages);
echo "Before Sort"."<br>";
//array before sorting
foreach($people_ages as $key=>$value)
{
echo $key."=>".$value."<br>";
}
echo '<hr>';
//performing sort
asort($people_ages);
echo "After Sort"."<br>";
//array after sorting
foreach($people_ages as $key=>$value)
{
echo $key."=>".$value."<br>";
}
Output:
4. arsort()
This function performs sorting on the given array and arranges the array’s values in a descending array. This example prints the array using a foreach loop and outputs the result as before sorting and after sorting.
Code:
//example to perform people_ages array
$people_ages = array('James' => 25, 'Rama' => 10, 'Mary' => 30, 'Alice' => 15, 'Radha' => 20);
// calculate length of array
$array_length = count($people_ages);
echo "Before Sort"."<br>";
//array before sorting
foreach($people_ages as $key=>$value)
{
echo $key."=>".$value."<br>";
}
echo '<hr>';
//performing sort
arsort($people_ages);
echo "After Sort"."<br>";
//array after sorting
foreach($people_ages as $key=>$value)
{
echo $key."=>".$value."<br>";
}
Output:
5. ksort()
This function performs sorting on the given array and arranges the keys of the array in ascending order. This example prints the array using a foreach loop and outputs the result as before sorting and after sorting.
Code:
//example to perform people_ages array
$people_ages = array('James' => 25, 'Rama' => 10, 'Mary' => 30, 'Alice' => 15, 'Radha' => 20);
// calculate length of array
$array_length = count($people_ages);
echo "Before Sort"."<br>";
//array before sorting
foreach($people_ages as $key=>$value)
{
echo $key."=>".$value."<br>";
}
echo '<hr>';
//performing sort
ksort($people_ages);
echo "After Sort"."<br>";
//array after sorting
foreach($people_ages as $key=>$value)
{
echo $key."=>".$value."<br>";
}
Output:
6. krsort()
This function performs sorting on the given array and arranges the keys of the array in descending order. This example prints the array using a foreach loop and outputs the result as before sorting and after sorting.
Code:
//example to perform people_ages array
$people_ages = array('James' => 25, 'Rama' => 10, 'Mary' => 30, 'Alice' => 15, 'Radha' => 20);
// calculate length of array
$array_length = count($people_ages);
echo "Before Sort"."<br>";
//array before sorting
foreach($people_ages as $key=>$value)
{
echo $key."=>".$value."<br>";
}
echo '<hr>';
//performing sort
krsort($people_ages);
echo "After Sort"."<br>";
//array after sorting
foreach($people_ages as $key=>$value)
{
echo $key."=>".$value."<br>";
}
Output:
7. natsort()
This function performs sorting on the given array and arranges the keys of the array in descending order. This example prints the array using a foreach loop and outputs the result as before sorting using assort() function and after sorting using natsort() function.
This function refreshes the output as the function randomizes the order of values in the given array. New numeric keys replace the keys mentioned in the array are assigned. For example, 10 is greater than 7 in a human being view, but according to the sorting algorithm 10 comes before 7.
We will use the natural flow of order.
Code:
<?php
$input = array("13 orange","14 Apple","15 3Banana","11 papaya","10 Grapes");;
$arr1 = $arr2 = $input;
echo "Before Sort"."<br>";
//array before sorting
foreach($input as $key=>$value)
{
echo $key."=>".$value."<br>";
}
echo '<hr>';
//performing sort
sort($arr1);
echo "Using asort function "."<br>";
//array before sorting
foreach($arr1 as $key=>$value)
{
echo $key."=>".$value."<br>";
}
echo '<hr>';
//performing sort
natsort($arr2);
echo "Using natsort function "."<br>";
foreach($arr2 as $key=>$value)
{
echo $key."=>".$value."<br>";
}
?>
Output :
8. natcasesort()
This function works the same as natsort() but is case insensitive.
Code:
$input = array("13 orange","14 Apple","15 Banana","11 papaya","10 Grapes");;
$arr1 = $arr2 = $input;
echo "Before Sort"."<br>";
//array before sorting
foreach($input as $key=>$value)
{
echo $key."=>".$value."<br>";
}
echo '<hr>';
//performing sort
sort($arr1);
echo "Using asort function "."<br>";
//array before sorting
foreach($arr1 as $key=>$value)
{
echo $key."=>".$value."<br>";
}
echo '<hr>';
//performing sort
natcasesort($arr2);
echo "Using natcasesort function "."<br>";
foreach($arr2 as $key=>$value)
{
echo $key."=>".$value."<br>";
}
Output :
9. usort()
This function performs sorting on the given array and arranges the values of the array in ascending order. This example prints the array using for loop and outputs the result.
In this program, the usort function takes two parameters: the input array and the other is the name of the function being called (here is compare).
This compare function is user-defined; also, the function is optional. This function returns 0 only if the condition in if block is satisfied, and else it will send -1 if the values compared is smaller than the other and 1 if the values compared is greater than the other.
Code:
function compare($x, $y) {
if($x == $y ){
return 0;
}
if($x < $y ){
return -1;
}
if($x > $y ){
return 1;
}
}
$numbers = array(10,4,5,3,20);
echo "Before Sort"."<br>";
//array after sorting
$array_length = count($numbers);
for($i=0;$i<$array_length;$i++)
{
echo $numbers[$i]."<br>";
}
echo '<hr>';
//performing sort
usort($numbers, "compare");
echo "After Sort"."<br>";
//array after sorting
$array_length = count($numbers);
for($i=0;$i<$array_length;$i++)
{
echo $numbers[$i]."<br>";
}
Output :
10. uasort()
This function performs sorting on the given array and arranges the array’s values in ascending order using the compare function.
Code:
<?php
function compare($x, $y) {
if($x == $y ){
return 0;
}
if($x < $y ){
return -1;
}
if($x > $y ){
return 1;
}
}
echo '<hr>';
//performing sort
$input = array("num1"=>10,"num2"=>4,"num3"=>3,"num4"=>5, "num5"=>20);
uasort($input, "compare");
echo "After Sort"."<br>";
//array after sorting
$array_length = count($input);
foreach($input as $key=>$value)
{
echo $key."=>".$value."<br>";
}
Output:
11. uksort()
This function performs sorting on the given array and arranges the array’s keys in ascending order using the compare function.
Code:
<?php
function compare($x, $y) {
if($x == $y ){
return 0;
}
if($x < $y ){
return -1;
}
if($x > $y ){
return 1;
}
}
echo '<hr>';
//performing sort
$input = array("num1"=>10,"num2"=>4,"num3"=>3,"num4"=>5, "num5"=>20);
uksort($input, "compare");
echo "After Sort"."<br>";
//array after sorting
$array_length = count($input);
foreach($input as $key=>$value)
{
echo $key."=>".$value."<br>";
}
Output :
12. shuffle()
This function refreshes the output as the function randomizes the order of values in the given array. New numeric keys replace the keys mentioned in the array are assigned.
Code:
$input = array('a'=>"Guava",'e'=>"Apple",'b'=>"Orange",'c'=>"Papaya", 'd' => "Banana");
echo "Before Sort"."<br>";
//array before sorting
foreach($input as $key=>$value)
{
echo $key."=>".$value."<br>";
}
echo '<hr>';
shuffle($input);
echo 'You need to refresh to see the new shuffle everytime'.'<br>';
$array_length = count($input);
echo '<hr>';
//array after sorting
$array_length = count($input);
foreach($input as $key=>$value)
{
echo $key."=>".$value."<br>";
}
Output:
Conclusion
In this article, most of the types of sorting are covered. The arrays are explained with examples. I hope you find it useful, informative and interesting.
以上がPHPでの並べ替えの詳細内容です。詳細については、PHP 中国語 Web サイトの他の関連記事を参照してください。