下面的文章《PHP 中的陣列》提供了在 PHP 中建立陣列的概述。數組是類似資料類型的集合。數組在單一變數中儲存多個值。當變數也可以儲存值時,為什麼需要數組呢?答案是因為儲存有限資料的值(例如數字5的計數)是可能的,但是當計數增加到例如100或200時,我們需要在100個變數中儲存100個值,這有點困難;因此,我們將其儲存在一個數組中。這就是使用數組的原因。
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文法:
variablename = array();
或
variablename[i] = value;
其中變數名稱是變數的名稱,i是鍵,或索引值是元素值。
建立陣列的範例
$colors = array("Red","Green","Blue");
為了計算陣列的長度,我們使用 count 關鍵字。
$length = count($colors); // output is 3
數組中的每個值稱為數組的一個元素。數組索引從0開始。數組中最後一個元素的索引是數組總長度減1。
在上面給出的範例中,Red 的索引為 0,Green 為 1,Blue 為 2。因此,借助索引或鍵來存取數組變得更加容易。為了取得數組每個索引處的值,我們循環遍歷給定的陣列。要循環數組,我們使用 foreach 迴圈或 for 迴圈。
像 foreach 和 for 這樣的迴圈用於迴圈遍歷數組。每個數組都有從 0 開始的索引,依此類推:
PHP中有三種類型的陣列;讓我們詳細了解每種類型的陣列:
在此數組類型中,索引始終是數字,它不能是字串。相反,它可以儲存任意數量的元素和任意類型的元素。
文法:
variable name = array("value1","value2","value3","value4")
代碼:
<?php //Example to demonstrate numeric array $input = array("Apple", "Orange", "Banana", "Kiwi"); //Here, to get these values we will write like echo $input[0] . "\n"; // will give Apple echo $input[1] . "\n"; // will give Orange echo $input[2] . "\n"; // will give Banana echo $input[3] . "\n"; // will give Kiwi // To get the length of array we will use count echo "The count of the array is " . count($input); // will give 4 echo "\n"; //To print the array we can use print_r($input); ?>
輸出:
或
宣告數值陣列的另一種方法是以下程式。在這個程式中,我們還將看到修改和列印值。
代碼:
<?php //Example to demonstrate numeric array in another way $input[0] = "Apple"; $input[1] = "Orange"; $input[2] = "Banana"; $input[3] = "Kiwi"; // To get Kiwi we will write like echo $input[3]."<br>"; // will give Kiwi //To modify Orange value $input[1] = "Mango"; // Now echo $input[1] will give Mango echo $input[1]."<br>"; // Mango //To print the array we can use print_r($input); ?>
輸出:
現在我們將學習如何使用for迴圈來遍歷陣列
代碼:
<?php //Example to demonstrate for loop on a numeric array //declaring the array $input = array("Apple", "Orange", "Banana", "Kiwi", "Mango"); //the for loop to traverse through the input array for($i=0;$i<count($input); $i++) { echo $input[$i]; echo "<br>"; } ?>
輸出:
這個陣列是鍵值對的形式,其中鍵是陣列的索引,值是陣列的元素。
文法:
$input = array("key1"=>"value1", "key2"=>"value2", "key3"=>"value3", "key4"=>"value4");
或
不使用陣列關鍵字宣告關聯陣列的另一種方法
$input[$key1] = $value1; $input[$key2] = $value2; $input[$key3] = $value3; $input[$key4] = $value4;
代碼:
<?php //Example to demonstrate associative array //declaring an array $input = array( "Jan"=>31, "Feb"=>28, "Mar"=>31, "Apr"=>30); // the for loop to traverse through the input array foreach($input as $in) { echo $in."<br>";} ?>
輸出:
這個數組是數組的數組,其中數組的值包含數組。
文法:
$input =array( array('value1', 'value2', 'value3'), array('value4', 'value5', 'value6'), array('value7', 'value8', 'value9'));,
代碼:
<?php //Example to demonstrate multidimensional array // declaring a multidimensional array $input = array ("colors"=>array ("Red", "Green", "Blue"), "fruits"=>array ("Apple", "Orange", "Grapes"), "cars"=>array ("Skoda", "BMW", "Mercedes") ); //the foreach loop to traverse through the input array foreach($input as $key=>$value) { echo $key .'--'. "<br>"; foreach($value as $k=>$v) {echo $v ." ";} echo "<br>"; } ?>
輸出:
或
關聯數組中的多維數組
代碼:
<?php //Example to demonstrate multidimensional array // declaring a multidimensional array $input = array( "The_Alchemist" => array ( "author" => "Paulo Coelho", "type" => "Fiction", "published_year" => 1988), "Managing_Oneself" => array( "author" => "Peter Drucker", "type" => "Non-fiction", "published_year" => 1999 ),"Measuring_the_World" => array( "author" => "Daniel Kehlmann", "type" => "Fiction", "published_year" => 2005 )); //the foreach loop to traverse through the input array //foreach to loop the outer array foreach($input as $book) { echo "<br>"; // foreach to loop the inner array foreach($book as $key=>$value) { echo $key." ". $value. "<br>";} }?>
輸出:
以下是 PHP 中陣列的方法:
此方法用於統計數組中元素的數量。
文法:
Count(array, mode)
需要計數的地方,模式是可選的。
代碼:
<?php //Example to demonstrate use of in_array method //declaring associative array $input=array('English','Hindi','Marathi'); //counting the number of elements in the given array echo count($input); ?>
輸出:
此方法接受兩個參數作為輸入;第一個參數是輸入數組,第二個參數是宣告的函數的名稱。此方法用於循環遍歷數組中的每個元素。
文法:
array_walk(array, function_name, parameter...)
其中需要陣列的地方需要 function_name
參數是可選的
代碼:
<?php //Example to demonstrate use of array_walk method //creating a function to print the key and values of the given array function fun($val, $k) { echo $k. " --" .$val ."\n"; } // declaring associative array $input=array("e"=>'English', "h"=>'Hindi', "m"=>'Marathi'); //passing this array as a first parameter to the function // array_walk, //second paramter as the name of the function being called array_walk($input,"fun"); ?>
Output:
This method performs a search on the array, whether the given array contains a particular value or not. If found or not found, it will execute respective if, else block
Syntax:
in_array(search_value, array_name)
Where both the parameters are required
Code:
<?php //Example to demonstrate use of in_array method // declaring associative array $input=array('English','Hindi','Marathi', "Maths", "Social Science"); // using in_array to find Maths in given array if(in_array("Maths", $input)) { echo "Found Maths in the given array"; } else { echo "Did not find Maths in the given array"; } ?>
Output:
This method removes the last element from the given array.
Syntax
array_pop(array_name)
Code:
<?php //Example to demonstrate use of array_pop method // declaring array $input=array('English','Hindi','Marathi'); // before using array_pop on the given array print_r($input); // after using array_pop method on the given array array_pop($input); echo "\n "; print_r($input); ?>
Output:
This method adds given elements at the end of the array.
Syntax:
array_push(array_name, value1, value2, ...)
Code:
<?php //Example to demonstrate use of array_push method // declaring array $input=array('English','Hindi','Marathi'); // before using array_push on the given array print_r($input); // after using array_push method on the given array array_push($input, "Economics", "Maths", "Social Science"); echo "\n"; //printing the array print_r($input); ?>
Output:
This method removes and returns the first element of the array.
Syntax:
array_shift(array_name)
Code:
<?php //Example to demonstrate use of array_push method // declaring array $input=array('English','Hindi','Marathi'); // before using array_shift on the given array print_r($input); echo "\n"; // after using array_shift method on the given array echo array_shift($input); ?>
Output:
This method inserts given elements into the beginning of the array.
Syntax:
array_unshift(array_name, value1, value2,…)
Code:
<?php //Example to demonstrate use of array_push method // declaring array $input=array('English','Hindi','Marathi'); // before using array_unshift on the given arrayprint_r($input); echo "\n"; // after using array_unshift method on the given array array_unshift($input, "Economics"); print_r($input); ?>
Output:
This method is used to reverse the elements of the array.
Syntax:
array_reverse(array_name, preserve)
where array_name is required,
preserve is optional
Code:
<?php //Example to demonstrate use of in_array method // declaring associative array $input=array("e"=>'English',"h"=>'Hindi',"m"=>'Marathi'); // array before reversing the elements print_r($input); echo "\n"; // printing the reverse // array after reversing the elements print_r(array_reverse($input)); ?>
Output:
This article covers all levels of concepts, simple and complex, of the topic arrays in PHP. I hope you found this article interesting and informative for the learning purpose.
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