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儿童节献礼:PHP数组操作汇总

2011-06-01

对于Web编程来说,最重要的就是存取和读写数据了。存储方式可能有很多种,可以是字符串、数组、文件的形式等。数组,可以说是PHP的数据应用中较重要的一种方式。PHP的数组函数众多,下面是我学习的小结,借此记之,便于以后鉴之。

1. 数组定义

数组的定义使用 array()方式定义,可以定义空数组:

<?php
    $number = array(1,3,5,7,9);
    //定义空数组
    $result = array();
    $color =array("red","blue","green");
    //自定义键值
    $language = (1=>"English",3=>"Chinese",5=>"Franch");
    //定义二维数组
    $two = array(
                "color"=>array("red","blue"),    //用逗号结尾
                "week"=>array("Monday","Friday")    //最后一句没有标点
    );
?>

2. 创建数组

compact()

compact()函数——将一个或多个变量(包含数组)转换为数组:array compact ( mixed $varname [, mixed $... ] )。

<?PHP
    $number = "1,3,5,7,9";
    $string = "I'm PHPer";
    $array = array("And","You?");
    $newArray = compact("number","string","array");
    print_r ($newArray);
?>

compact()函数用于将两个或多个变量转换为数组,当然也包含数组变量。其参数是变量的名称而非带有$全名。相反的函数是extract()作用顾名思义就是将数组转换为单个的字符串,键值作为其字符串名称,数组值作为字符串的值。

运行结果:

Array ( 
	[number] => 1,3,5,7,9 
	[string] => I'm PHPer 
	[array] => Array ( [0] => And [1] => You? ) 
)

array_combine()

array_combine()——将两个数组重组成一个数组,一个作键值一个做的值:array array_combine ( array $keys , array $values )

<?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函数不多说了,谁看了都明白。

运行结果:

Array ( [1] => I [3] => Am [5] => A [7] => PHP [9] => er )

range()

range()函数——创建指定范围的数组:

<?PHP
    $array1 = range(0,100,10);//0为起始值,100为结束值,10为步进值(默认步进值为1).
    print_r($array1);
    echo"<br />";
    $array2 = range("A","Z");
    print_r($array2);
    echo "<br />";
    $array3 = range("z","a");
    print_r($array3);
?>

array_fill()

array_fill()函数——填充数组函数:

<?PHP
        $array = range(1,10);
        $fillarray = range("a","d");
        $arrayFilled = array_fill(0,5,$fillarray);//这里的$fillarray可以是字符串,如"test".
        echo "<pre>";
        print_r ($arrayFilled);
        echo "</pre>";
        $keys = array("string","2",9,"SDK","PK");
        $array2 = array_fill_keys($keys,"testing");
        echo "<pre>";
        print_r ($array2);
        echo "</pre>";
?>

运行结果:

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
)

3. 数组的遍历

foreach遍历

foreach (array_expression as $value){}

foreach (array_expression as $key => $value){}

<?PHP
	$speed = array(50,120,180,240,380);
	foreach($speed as $keys=>$values){
		echo $keys."=>".$values."<br />";
	}
?>

运行结果:

0=>50
1=>120
2=>180
3=>240
4=>380

while循环遍历

while循环遍历一般结合list函数,以下是实例

	<?PHP
        $staff = array(
            array("姓名","性别","年龄"),
            array("小张","男",24),
            array("小王","女",25),
            array("小李","男",23)
        );
        echo "<table border=2>";
        while(list($keys,$value) = each($staff)){
            list($name,$sex,$age) = $value;
            echo "<tr><td>$name</td><td>$sex</td><td>$age</td></tr>";
        }
        echo "</table>";
       ?>

for循环遍历

<?PHP
    $speed = range(0,220,20);
    for($i =0;$i<count($speed);$i++) {
        echo $speed[$i]." ";
    }
?>

运行结果:

0 20 40 60 80 100 120 140 160 180 200 220 

4. 数组的指针操作

涉及函数包括reset、prev、end、next、current、each。

实例一:next 与 prev

<?PHP
    $speed = range(0,220,20);
    echo current($speed);//输出当前位置的值(在数组的开头位置)
    $i = rand(1,11);
    while($i--){
        next($speed);//指针从当前位置向后移动一位
    }
    echo current($speed);//输出当前位置的值
    echo "<br />";
    echo prev($speed);//输出前一位置数组值
    echo "<br />";
    echo reset($speed);//重置数组的指针,将指针指向起始位置
    echo "<br />";
    echo end($speed);//输出最后位置的数组值
    echo "<br />";
?>

运行结果:

0220
200
0
220

实例二:each函数指针操作

<?PHP
    $speed = range(0,200,40);
    echo "each实现指针下移 <br />";
    echo "0挡的速度是".current(each($speed))."<br />";
    echo "1挡的速度是".current(each($speed))."<br />";
    echo "2挡的速度是".current(each($speed))."<br />";
    echo "3挡的速度是".current(each($speed))."<br />";
    echo "4挡的速度是".current(each($speed))."<br />";
    echo "5挡的速度是".current(each($speed))."<br />";
    echo "使用each函数实现数组指针的移动,进行数组遍历 <br />";
    reset($speed);//这里是将数组指针指向数组首
    while(list($key,$value)=each($speed)){
        echo $key."=>".$value."<br />";
    }
?>

运行结果:

each实现指针下移 
0挡的速度是0
1挡的速度是40
2挡的速度是80
3挡的速度是120
4挡的速度是160
5挡的速度是200
使用each函数实现数组指针的移动,进行数组遍历 
0=>0
1=>40
2=>80
3=>120
4=>160
5=>200

5. 数组的增添删改操作

增添数组成员

实例一:$num[] = value直接赋值追加到数组末尾:

	<?PHP
        $num = array(1=>80,2=>120,3=>160);
        echo "使用表达式添加数组成员<br />";
        $num[]=240;
        print_r($num);
      ?>

运行结果:

使用表达式添加数组成员
Array ( [0] => 80 [1] => 120 [2] => 160 [3] => 240 )

实例二:array_pad函数,数组数组首尾选择性追加

	<?PHP
        $num = array(1=>80,2=>120,3=>160);
        $num = array_pad($num,4,200);
        echo "使用array_pad函数向数组尾部添加成员<br />";
        print_r($num);
        echo "<br />array_pad 还可以填充数组首部<br />";
        $num = array_pad($num,-8,40);
        print_r($num);
    ?>

运行结果:

使用array_pad函数向数组尾部添加成员
Array ( [0] => 80 [1] => 120 [2] => 160 [3] => 200 ) 
array_pad 还可以填充数组首部
Array ( [0] => 40 [1] => 40 [2] => 40 [3] => 40 [4] => 80 [5] => 120 [6] => 160 [7] => 200 )

实例三:入栈操作追加(array_push):

	<?PHP
        $num = array(1=>80,2=>120,3=>160);
        array_push($num,200,240,280);//可以自己追加,直接加在数组结尾
        print_r($num);
    ?>

运行结果:

Array ( [1] => 80 [2] => 120 [3] => 160 [4] => 200 [5] => 240 [6] => 280 )

实例四:array_unshift()在开头添加数组成员

	<?PHP
        $num = array(1=>80,2=>120,3=>160);
        array_unshift($num,0,40);//可以自己追加,直接加在数组结尾
        print_r($num);
    ?>

运行结果:

Array ( [0] => 0 [1] => 40 [2] => 80 [3] => 120 [4] => 160 )

注意:array_unshift()函数使用后数组的键值将会从0开始!

删减数组成员

实例一:unset()命令删除数组成员或数组:

	<?PHP
        $num = array_fill(0,5,rand(1,10));
        print_r($num);
        echo "<br />";
        unset($num[4]);
        print_r($num);
        echo "<br />";
        unset($num);
        if(is_array){
            echo "unset命令不能删除整个数组";
        }else{
            echo "unset命令可以删除数组";
        }
    ?>

运行结果:(运行出错及说明数组也被删除,不再存在)

Array ( [0] => 9 [1] => 9 [2] => 9 [3] => 9 [4] => 9 ) 
Array ( [0] => 9 [1] => 9 [2] => 9 [3] => 9 ) 

Notice: Use of undefined constant is_array - assumed 'is_array' in H:\wamp\www\testing\editorplus\test.php on line 21
unset命令不能删除整个数组

实例二:array_splice()函数删除数组成员

<?php
        $a=array("red", "green", "blue", "yellow");   
        count ($a); //得到4   
        array_splice($a,1,1); //删除第二个元素   
        count ($a); //得到3   
        echo $a[2]; //得到yellow   
        echo $a[1]; //得到blue   
?>   

实例三:array_unique删除数组中的重复值:

	<?php
        $a=array("red", "green", "blue", "yellow","blue","green");   
        $result = array_unique($a);
        print_r($result);
    ?>

运行结果:

Array ( [0] => red [1] => green [2] => blue [3] => yellow )

实例四:array_merge、array_merge_recursive合并数组

	<?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 "<pre>";
        print_r($result);
        echo "</pre>";
        $result = array_merge_recursive($array1,$array2,$array3,$array4,$array5);
        echo "<pre>";
        print_r ($result);
        echo "</pre>";
    ?>

运行结果:

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的键名是数字的将重新建立索引;遇到相同的字符串键名时,后面的将覆盖前面的。 2. array_merge_recursive函数的作用是将相同字符串的键名单元整合成一个数组。

6. 数组的键值和值操作

实例一:in_array()检测数组中是否有某个值存在

	<?php
        $array = range(0,9);
        if(in_array(9,$array)){
            echo "数组中存在";
        }
    ?>   

运行结果:数组中存在

实例二:key()取得数组当前的键名:

	<?php
        $array = range(0,9);
        $num = rand(0,8);
        while($num--)
        next($array);
        $key = key($array);
        echo $key;
    ?>

此实例结果为动态结果,范围(0-8),不做结果演示。

实例三:list()函数把数组中的值赋给指定变量:

<?PHP
        $staff = array(
            array("姓名","性别","年龄"),
            array("小张","男",24),
            array("小王","女",25),
            array("小李","男",23)
        );
        echo "<table border=2>";
        while(list($keys,$value) = each($staff)){
            list($name,$sex,$age) = $value;
            echo "<tr><td>$name</td><td>$sex</td><td>$age</td></tr>";
        }
        echo "</table>";
?>

实例四:array_flip()交换数组的键值和值:

	<?PHP
        $array = array("red","blue","yellow","Black");
        print_r($array);
        echo "<br />";
        $array = array_flip($array);
        print_r($array);
       ?>

运行结果:

Array ( [0] => red [1] => blue [2] => yellow [3] => Black ) 
Array ( [red] => 0 [blue] => 1 [yellow] => 2 [Black] => 3 )

实例五:array_keys()、array_values()返回数组中所有的键值和值:

	<?PHP
        $array = array("red","blue","yellow","Black");
        $result = array_keys($array);
        print_r($result);
        echo "<br />";
        $result = array_values($array);
        print_r($result);
       ?>

运行结果:

Array ( [0] => 0 [1] => 1 [2] => 2 [3] => 3 ) 
Array ( [0] => red [1] => blue [2] => yellow [3] => Black )

实例六:array_search()搜索数值:

	<?PHP
        $array = array("red","blue","yellow","Black");
        $result = array_search("red",$array);
        if(($result === NULL)){
            echo "不存在数值red";
        }else{
            echo "存在数值 $result";
        }
       ?>

结果:存在数值 0

函数array_search()返回的值可能为false或0或NULL,所以在判断时注意要用"==="

7. 数组的排序

实例一:sort()、rsort()/asort()、arsort()对数组排序:

<?PHP
    $array = array("b","c","d","a");
    sort($array);//从低到高排序
    print_r($array);
    echo "<br />";
    rsort($array);//逆向排序
    print_r($array);
?>

结果:

Array ( [0] => a [1] => b [2] => c [3] => d ) 
Array ( [0] => d [1] => c [2] => b [3] => a )

sort()、rsort()函数对数组进行从低到高的排序,返回结果为bool值;

asort()、arsort()函数是保留键值的排序,排序后键值不重新索引。

实例二:将数组顺序打乱——shuffle()函数:

<?PHP
    $array = array("a","b","c","d");
    shuffle($array);//从低到高排序
    print_r($array);
?>

结果为动态结果:

Array ( [0] => c [1] => a [2] => d [3] => b )

shuffle的结果有点随机的意味,每次刷新都不一样。

实例三:array_reverse()数组反向:

<?PHP
    $array = array("d","b","a","c");
    $array = array_reverse($array);//从低到高排序
    print_r($array);
?>

运行结果:

Array ( [0] => c [1] => a [2] => b [3] => d )

实例四:自然排序算法——natsort()和natcasesort();

<?PHP
    $array = array("sort2","Sort5","sort1","sort4");
    natsort($array);//从低到高排序
    print_r($array);
    echo "<br />";
    natcasesort($array);
    print_r($array);
?>

结果:

Array ( [1] => Sort5 [2] => sort1 [0] => sort2 [3] => sort4 ) 
Array ( [2] => sort1 [0] => sort2 [3] => sort4 [1] => Sort5 )

natsort()、natcasesort()对数组进行自然排序,就是使用数字的正常排序算法。natcasesort会忽略大小写。

实例五:对数组进行键值排序ksort():

<?PHP
    $array = array(1=>"sort2",4=>"Sort5",2=>"sort1",3=>"sort4");
    ksort($array);//从低到高排序
    print_r($array);
?>

结果:

Array ( [1] => sort2 [2] => sort1 [3] => sort4 [4] => Sort5 )

注意:ksort()函数重新建立了索引。

8. 数组的其他用法

   cout($array) --------统计数组的单元个数
  array_diff($array1,$array2)----------统计数组之间的不同点,返回第一个数组中有而第二个数组中没有的。
  array_diff_assoc($array1,$array2)---------同array_diff(),只是它对键值也比较
  array_diff_key($array1,$array2)------------比较键值
  array_product($array)-----------返回数组的所有数的乘积
  array_sum($array)--------------所有数值的和
  array_rand($array,$n)----------在$array数组中取出$n个数值,返回数组
  array_intersect($array1,$array2)----------------取得两个数组的交集
  array_intersect_assoc($array1,$array2)---------------在array_intersect 的基础上进行键值比较
  array_intersect_key($array1,$array2)-----------------比较两个数组键值的交集

总结

数组的使用在PHP中至关重要,由于PHP没有指针,所以数组承担了很大的数据操作任务。学好数组,才能把PHP应用的得心应手,这里所列均是常用的PHP数组相关的函数及用法,欢迎一起学习!

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