php数组的使用技巧,PHP数组操作汇总
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51自学网 2016-09-17 http://www.wanshiok.com |
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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
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