php 數組操作函數學習筆記
來源:程序員人生 發布時間:2014-04-29 00:07:13 閱讀次數:3909次
在php中數組是我們開發應用中不可少的了部份,下面我來把我自己學習php數組的一些操作給各位同學分享一下,希望有需要了解的同學可進入參考。
對于Web編程來說,最重要的就是存取和讀寫數據了。存儲方式可能有很多種,可以是字符串、數組、文件的形式等。數組,可以說是PHP的數據應用中較重要的一種方式。PHP的數組函數眾多,下面是我學習的小結,借此記之,便于以后鑒之。
. 數組定義
數組的定義使用 array()方式定義,可以定義空數組,代碼如下:
- <?php
- $number = array(1,3,5,7,9);
-
- $result = array();
- $color =array("red","blue","green");
-
- $language = (1=>"English",3=>"Chinese",5=>"Franch");
-
- $two = array(
- "color"=>array("red","blue"),
- "week"=>array("Monday","Friday")
- );
- ?>
創建數組
compact()
compact()函數——將一個或多個變量(包含數組)轉換為數組:array compact ( mixed $varname [, mixed $... ] )。
實例代碼如下:
- <?php
- $number = "1,3,5,7,9";
- $string = "I'm PHPer";
- $array = array("And","You?");
- $newArray = compact("number","string","array");
- print_r ($newArray);
- ?>
ompact()函數用于將兩個或多個變量轉換為數組,當然也包含數組變量。其參數是變量的名稱而非帶有$全名。相反的函數是extract()作用顧名思義就是將數組轉換為單個的字符串,鍵值作為其字符串名稱,數組值作為字符串的值。
運行結果:
- Array (
- [number] => 1,3,5,7,9
- [string] => I'm PHPer
- [array] => Array ( [0] => And [1] => You? )
- )
array_combine()
array_combine()——將兩個數組重組成一個數組,一個作鍵值一個做的值:array array_combine ( array $keys , array $values )
代碼如下:
- <?php
- $number = array("1","3","5","7","9");
- $array = array("I","Am","A","PHP","er");
- $newArray = array_combine($number,$array);
- print_r ($newArray);
- ?>
array_combine函數不多說了,誰看了都明白。
運行結果:
Array ( [1] => I [3] => Am [5] => A [7] => PHP [9] => er )
range()
range()函數——創建指定范圍的數組,代碼如下:
- <?php
- $array1 = range(0,100,10);
- print_r($array1);
- echo"";
- $array2 = range("A","Z");
- print_r($array2);
- echo "";
- $array3 = range("z","a");
- print_r($array3);
- ?>
array_fill()
array_fill()函數——填充數組函數,代碼如下:
- <?php
- $array = range(1,10);
- $fillarray = range("a","d");
- $arrayFilled = array_fill(0,5,$fillarray);
- echo "
- ";
- print_r ($arrayFilled);
- echo "";
- $keys = array("string","2",9,"SDK","PK");
- $array2 = array_fill_keys($keys,"testing");
- echo "
- ";
- print_r ($array2);
- echo "";
- ?>
運行結果:
- Array
- (
- [0] => Array
- (
- [0] => a
- [1] => b
- [2] => c
- [3] => d
- )
- [1] => Array
- (
- [0] => a
- [1] => b
- [2] => c
- [3] => d
- )
- [2] => Array
- (
- [0] => a
- [1] => b
- [2] => c
- [3] => d
- )
- [3] => Array
- (
- [0] => a
- [1] => b
- [2] => c
- [3] => d
- )
- [4] => Array
- (
- [0] => a
- [1] => b
- [2] => c
- [3] => d
- )
- )
- Array
- (
- [string] => testing
- [2] => testing
- [9] => testing
- [SDK] => testing
- [PK] => testing
- )
數組的遍歷
foreach遍歷
foreach (array_expression as $value){}
foreach (array_expression as $key => $value){}
實例代碼如下:
- $speed = array(50,120,180,240,380);
- foreach($speed as $keys=>$values){
- echo $keys."=>".$values."";
- }
運行結果:
- 0=>50
- 1=>120
- 2=>180
- 3=>240
- 4=>380
while循環遍歷
while循環遍歷一般結合list函數,以下是實例,代碼如下:
- <?php
- $staff = array(
- array("姓名","性別","年齡"),
- array("小張","男",24),
- array("小王","女",25),
- array("小李","男",23)
- );
- echo "";
- while(list($keys,$value) = each($staff)){
- list($name,$sex,$age) = $value;
- echo "$name$sex$age";
- }
- echo "";
- ?>
for循環遍歷
實例代碼如下:
- <?php
- $speed = range(0,220,20);
- for($i =0;$i<count($speed);$i++) {
- echo $speed[$i]." ";
- }
- ?>
運行結果:0 20 40 60 80 100 120 140 160 180 200 220
數組的指針操作
涉及函數包括reset、prev、end、next、current、each。
實例一:next 與 prev,代碼如下:
- <?php
- $speed = range(0,220,20);
- echo current($speed);
- $i = rand(1,11);
- while($i--){
- next($speed);
- }
- echo current($speed);
- echo "";
- echo prev($speed);
- echo "";
- echo reset($speed);
- echo "";
- echo end($speed);
- echo "";
- ?>
運行結果:
0220 200 0 220
實例二:each函數指針操作,代碼如下:
- <?php
- $speed = range(0,200,40);
- echo "each實現指針下移 ";
- echo "0擋的速度是".current(each($speed))."";
- echo "1擋的速度是".current(each($speed))."";
- echo "2擋的速度是".current(each($speed))."";
- echo "3擋的速度是".current(each($speed))."";
- echo "4擋的速度是".current(each($speed))."";
- echo "5擋的速度是".current(each($speed))."";
- echo "使用each函數實現數組指針的移動,進行數組遍歷 ";
- reset($speed);
- while(list($key,$value)=each($speed)){
- echo $key."=>".$value."";
- }
- ?>
運行結果:
each實現指針下移
0擋的速度是0
1擋的速度是40
2擋的速度是80
3擋的速度是120
4擋的速度是160
5擋的速度是200
使用each函數實現數組指針的移動,進行數組遍歷
- 0=>0
- 1=>40
- 2=>80
- 3=>120
- 4=>160
- 5=>200
數組的增添刪改操作
增添數組成員
實例一:$num[] = value直接賦值追加到數組末尾,實例代碼如下:
- <?php
- $num = array(1=>80,2=>120,3=>160);
- echo "使用表達式添加數組成員";
- $num[]=240;
- print_r($num);
- ?>
運行結果:
使用表達式添加數組成員
Array ( [0] => 80 [1] => 120 [2] => 160 [3] => 240 )
實例二:array_pad函數,數組數組首尾選擇性追加,代碼如下:
- <?php
- $num = array(1=>80,2=>120,3=>160);
- $num = array_pad($num,4,200);
- echo "使用array_pad函數向數組尾部添加成員";
- print_r($num);
- echo "array_pad 還可以填充數組首部";
- $num = array_pad($num,-8,40);
- print_r($num);
- ?>
運行結果:
使用array_pad函數向數組尾部添加成員
Array ( [0] => 80 [1] => 120 [2] => 160 [3] => 200 )
array_pad 還可以填充數組首部
Array ( [0] => 40 [1] => 40 [2] => 40 [3] => 40 [4] => 80 [5] => 120 [6] => 160 [7] => 200 )
實例三:入棧操作追加(array_push),代碼如下:
- <?php
- $num = array(1=>80,2=>120,3=>160);
- array_push($num,200,240,280);
- print_r($num);
- ?>
運行結果:
Array ( [1] => 80 [2] => 120 [3] => 160 [4] => 200 [5] => 240 [6] => 280 )
實例四:array_unshift()在開頭添加數組成員,代碼如下:
- <?php
- $num = array(1=>80,2=>120,3=>160);
- array_unshift($num,0,40);
- print_r($num);
- ?>
運行結果:
Array ( [0] => 0 [1] => 40 [2] => 80 [3] => 120 [4] => 160 )
注意:array_unshift()函數使用后數組的鍵值將會從0開始!
刪減數組成員
實例一:unset()命令刪除數組成員或數組,代碼如下:
- <?php
- $num = array_fill(0,5,rand(1,10));
- print_r($num);
- echo "";
- unset($num[4]);
- print_r($num);
- echo "";
- unset($num);
- if(is_array){
- echo "unset命令不能刪除整個數組";
- }else{
- echo "unset命令可以刪除數組";
- }
- ?>
運行結果:(運行出錯及說明數組也被刪除,不再存在)
Array ( [0] => 9 [1] => 9 [2] => 9 [3] => 9 [4] => 9 )
Array ( [0] => 9 [1] => 9 [2] => 9 [3] => 9 )
unset命令不能刪除整個數組
實例二:array_splice()函數刪除數組成員,代碼如下:
- $a=array("red", "green", "blue", "yellow");
- count ($a);
- array_splice($a,1,1);
- count ($a);
- echo $a[2];
- echo $a[1];
實例三:array_unique刪除數組中的重復值,代碼如下:
- <?php
- $a=array("red", "green", "blue", "yellow","blue","green");
- $result = array_unique($a);
- print_r($result);
- ?>
運行結果:
Array ( [0] => red [1] => green [2] => blue [3] => yellow )
實例四:array_merge、array_merge_recursive合并數組,代碼如下:
- <?php
- $array1 = array("r"=>"red",1,2,3,4);
- $array2 = array("b"=>"blue",4=>5,6,7,8,9);
- $array3 = array("r"=>"read",4=>10,2=>11);
- $array4 = array(
- array(4=>10),
- array(7=>13)
- );
- $array5 = array(
- array(4=>11),
- array(6=>12)
- );
- $result = array_merge($array1,$array2,$array3,$array4,$array5);
- echo "
- ";
- print_r($result);
- echo "";
- $result = array_merge_recursive($array1,$array2,$array3,$array4,$array5);
- echo "
- ";
- print_r ($result);
- echo "";
- ?>
運行結果:
- Array
- (
- [r] => read
- [0] => 1
- [1] => 2
- [2] => 3
- [3] => 4
- [b] => blue
- [4] => 5
- [5] => 6
- [6] => 7
- [7] => 8
- [8] => 9
- [9] => 10
- [10] => 11
- [11] => Array
- (
- [4] => 10
- )
- [12] => Array
- (
- [7] => 13
- )
- [13] => Array
- (
- [4] => 11
- )
- [14] => Array
- (
- [6] => 12
- )
- )
- Array
- (
- [r] => Array
- (
- [0] => red
- [1] => read
- )
- [0] => 1
- [1] => 2
- [2] => 3
- [3] => 4
- [b] => blue
- [4] => 5
- [5] => 6
- [6] => 7
- [7] => 8
- [8] => 9
- [9] => 10
- [10] => 11
- [11] => Array
- (
- [4] => 10
- )
- [12] => Array
- (
- [7] => 13
- )
- [13] => Array
- (
- [4] => 11
- )
- [14] => Array
- (
- [6] => 12
- )
- )
注:1. array_merge的鍵名是數字的將重新建立索引;遇到相同的字符串鍵名時,后面的將覆蓋前面的。 2. array_merge_recursive函數的作用是將相同字符串的鍵名單元整合成一個數組。
數組的鍵值和值操作
實例一:in_array()檢測數組中是否有某個值存在,代碼如下:
- $array = range(0,9);
- if(in_array(9,$array)){
- echo "數組中存在";
- }
運行結果:數組中存在
實例二:key()取得數組當前的鍵名,代碼如下:
- <?php
- $array = range(0,9);
- $num = rand(0,8);
- while($num--)
- next($array);
- $key = key($array);
- echo $key;
- ?>
此實例結果為動態結果,范圍(0-8),不做結果演示。
實例三:list()函數把數組中的值賦給指定變量,代碼如下:
- <?Php
- $staff = array(
- array("姓名","性別","年齡"),
- array("小張","男",24),
- array("小王","女",25),
- array("小李","男",23)
- );
- echo "";
- while(list($keys,$value) = each($staff)){
- list($name,$sex,$age) = $value;
- echo "$name$sex$age";
- }
- echo "";
- ?>
實例四:array_flip()交換數組的鍵值和值,代碼如下:
- <?Php
- $array = array("red","blue","yellow","Black");
- print_r($array);
- echo "";
- $array = array_flip($array);
- print_r($array);
- ?>
-
-
-
代碼如下:
- <?php
- $array = array("red","blue","yellow","Black");
- $result = array_keys($array);
- print_r($result);
- echo "";
- $result = array_values($array);
- print_r($result);
- ?>
-
-
-
實例六:array_search()搜索數值,代碼如下:
- <?php
- $array = array("red","blue","yellow","Black");
- $result = array_search("red",$array);
- if(($result === NULL)){
- echo "不存在數值red";
- }else{
- echo "存在數值 $result";
- }
- ?>
-
函數array_search()返回的值可能為false或0或NULL,所以在判斷時注意要用"==="
數組的排序
實例一:sort()、rsort()/asort()、arsort()對數組排序,代碼如下:
- <?php
- $array = array("b","c","d","a");
- sort($array);
- print_r($array);
- echo "";
- rsort($array);
- print_r($array);
- ?>
-
-
-
sort()、rsort()函數對數組進行從低到高的排序,返回結果為bool值;
asort()、arsort()函數是保留鍵值的排序,排序后鍵值不重新索引。
實例二:將數組順序打亂——shuffle()函數,代碼如下:
- <?php
- $array = array("a","b","c","d");
- shuffle($array);
- print_r($array);
- ?>
-
-
shuffle的結果有點隨機的意味,每次刷新都不一樣。
實例三:array_reverse()數組反向,代碼如下:
- <?php
- $array = array("d","b","a","c");
- $array = array_reverse($array);
- print_r($array);
- ?>
-
-
實例四:自然排序算法——natsort()和natcasesort();代碼如下:
- <?php
- $array = array("sort2","Sort5","sort1","sort4");
- natsort($array);
- print_r($array);
- echo "";
- natcasesort($array);
- print_r($array);
- ?>
-
-
-
natsort()、natcasesort()對數組進行自然排序,就是使用數字的正常排序算法。natcasesort會忽略大小寫。
實例五:對數組進行鍵值排序ksort(),代碼如下:
- <?php
- $array = array(1=>"sort2",4=>"Sort5",2=>"sort1",3=>"sort4");
- ksort($array);
- print_r($array);
- ?>
-
-
注意:ksort()函數重新建立了索引。
數組的其他用法
代碼如下:
- array = array ('A', 'B', 'C' );
-
- array_unshift ( $array, 'E', 'F', 'G' );
- var_dump ( $array );
- $array = array ('A', 'B', 'C' );
-
- array_push ( $array, 'E', 'F'
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