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。
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 ); ?>
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$fillarray可以是字符串,如"test". echo "<pre class="brush:php;toolbar:false">"; print_r ($arrayFilled); echo "
"; print_r ($array2); echo "
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 )
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
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
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 class="brush:php;toolbar:false">"; print_r($result); echo "
"; print_r ($result); echo "
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。
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"==="
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($array); ?>
结果:
Array ( [1] => sort2 [2] => sort1 [3] => sort4 [4] => Sort5 )
注意:ksort()函数重新建立了索引。
cout($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
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!