[PHP_Day 4]_基本語法part4_Array、HashTable

陣列(可以不只侷限一種型態，可以是Object)
陣列的初始化有兩種寫一種是透過array小括號
一種則是直接一組方括號
可以用print_r來輸出整個array索引對應成員

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<?php $arrStr = array("apple","banana","cherry","桃子","葡萄柚"); var_dump($arrStr);//陣列中string各自大小(Byte)，一個中文字佔3Byte。 echo "<br/>"; print_r($arrStr); echo "<br/>"; echo $arrStr[3]; echo "<br/>"; $arrStr2 = ["a1","a2","a3"]; var_dump($arrStr2); echo "<br/>"; print_r($arrStr2); echo "<br/>"; echo $arrStr2[1]; echo "<br/>"; $arrInt = [15,68,77,98]; var_dump($arrInt); echo "<br/>"; print_r($arrInt); echo "<br/>"; $arrFloat = [9.8,5.4,3.1,6.24]; var_dump($arrFloat); echo "<br/>"; print_r($arrFloat); echo "<br/>"; $arrMultiType = [9.8,7,"apple"]; var_dump($arrMultiType); echo "<br/>"; print_r($arrMultiType); echo "<br/>"; ?>

在PHP中Array跟HashTable(有點像C#的Dictionary->Key-Val)是用
同一方式在定義(同一件事情)
只是寫法有別於Array額外擴充跟改寫
預設會自動分配index從0開始的Key
事實上也可自定義客制化Key識別(但盡量不要型態參差不一致)
要用客制化Key就統一都字串不要穿插int或float

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<?php $arr1 = array( 1 => "banana", 0 => "apple" ); print_r($arr1); /* //預設都是index從0開始(換成HashTable則是Key依序0,1) $arr1 = array( 0 => "apple", 1 => "banana" ); */ echo "<br/>"; $arr2 = array( "fruit2" => "banana", "fruit1" => "apple" ); print_r($arr2); echo "<br/>"; echo $arr2["fruit2"]; ?>

Array的新增及刪除異動

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<?php $arr1 = array( "apple", "banana" ); print_r($arr1); echo "<br/>"; //新增(從尾端) array_push($arr1,"cake"); array_push($arr1,"date"); print_r($arr1); echo "<br/>"; //刪除(從尾端) array_pop($arr1); print_r($arr1); echo "<br/>"; //Array ( [0] => apple [1] => banana [2] => cake ) //於特定index位置之後穿插(類似將兩個array合併在一塊) //參數3代表是否要取代掉原本的(0:不要) //Array ( [0] => apple [1] => banana [2] => cake ) //array_splice($arr1,1,0,["pink"]);//Array ( [0] => apple [1] => pink [2] => banana [3] => cake ) array_splice($arr1,1,1,["pink"]); //Array ( [0] => apple [1] => pink [2] => cake ) print_r($arr1); echo "<br/>"; //刪除特定index的元素(不會重新調整index)--->寫的時候容易導致無法確切得知元素位置 //Array ( [0] => apple [1] => pink [2] => cake ) //Array ( [0] => apple [2] => cake ) unset($arr1[1]);//delete [1] => pink print_r($arr1); echo "<br/>"; //array 轉 json string $arr2 = array( "apple", "banana", "cake" ); echo json_encode($arr2); echo "<br/>"; echo json_encode($arr1); ?>