一維陣列

陣列是儲存格的概念，從第 0 個儲存格開始，在儲存格內放入值。

用 array() 宣告陣列

• 索引式陣列 (Indexed Array)

<?php
    $colors = array("red", "green", "blue");

    echo $colors[0]."<br>";
    echo $colors[1]."<br>";
    echo $colors[2]."<br>";
?>

• 關聯式陣列 (Associative Array)

<?php
    $scores = array("math" => 85, "english" => 90, "science" => 76);

    echo $scores["math"]."<br>";
    echo $scores["english"]."<br>";
    echo $scores["science"]."<br>";
?>

這兩者差別在索引的形式，內部的值皆可放數字及字串。

我們可以用 var_dump() 和 print_r() 來看陣列的所有內容

<?php
    $colors = array("red", "green", "blue");

    var_dump($colors);  //較詳細
    echo "<br>";
    print_r($colors);   //較簡潔
    echo "<br>";
?>

<?php
    $scores = array("math" => 85, "english" => 90, "science" => 76);

    var_dump($scores);  //較詳細
    echo "<br>";
    print_r($scores);   //較簡潔
    echo "<br>";
?>

指定索引

我們也可以直接指定索引及變數，將資料指派進去

<?php
    $colors = array("red", "green", "blue");
    $colors[3] = "yellow";
    $colors[5] = 123;

    print_r($colors);
    echo "<br>";
?>

<?php
    $scores = array("math" => 85, "english" => 90, "science" => 76);
    $scores["chinese"] = 666;
    $scores[4] = "100分";

    print_r($scores);
    echo "<br>";
?>

不指定索引

若不指定索引，預設為數字編號

<?php
    $cityArray[] = "Taipei";
    $cityArray[] = "Taichung";
    $cityArray[] = "Tainan";
    
    print_r($cityArray);
?>

一維陣列範例

<?php
    $scores["math"] = 87;
    $scores["english"] = 92;
    $scores["science"] = 79;

    $subject = "english";
    echo "My ".$subject." test is ".$scores[$subject]." points.<br>";
    $subject = "math";
    echo "My ".$subject." test is ".$scores[$subject]." points.<br>";
?>

二維陣列

宣告二維陣列

<?php
    $numbers = array(array(1,2,3), array(4,5,6), array(7,8,9));

    print_r($numbers);
    echo "<br>".$numbers[1][0];
?>

有點類似 HTML 提過的表格的概念

<?php
    $data = array(
        "Elsa"=>array(
            "Math"=>78,
            "Eng"=>98
        ),
        "Anna"=>array(
            "Math"=>80,
            "Eng"=>56
        )
     );

     print_r($data);
     echo "<br>".$data["Anna"]["Math"];
?>

<?php
    $student["Elsa"]= array("Math"=>78,"Eng"=>98);
    $student["Anna"]= array("Math"=>80,"Eng"=>56);

    print_r($student);
    echo "<br>".$student["Anna"]["Math"];
?>