php 数组

{php 数组}

对于网页编程来说，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，今天学习了数组，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……
 

一、数组定义：

数组的定义使用 array（）方式定义，可以定义空数组：

.foreach遍历：

<? 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 )； ?>

二、创建数组：

创建数组包含的函数有compact()、

1.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? ) )

2.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 )

3.range()函数——创建指定范围的数组：

不多说了，直接上实例——

<? 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 ); ?>

range()函数的默认步进值是1！

运行结果：

 

Array ( [ 0 ] => 0 [ 1 ] => 10 [ 2 ] => 20 [ 3 ] => 30 [ 4 ] => 40 [ 5 ] => 50 [ 6 ] => 60 [ 7 ] => 70 [ 8 ] => 80 [ 9 ] => 90 [ 10 ] => 100 ) Array ( [ 0 ] => A [ 1 ] => B [ 2 ] => C [ 3 ] => D [ 4 ] => E [ 5 ] => F [ 6 ] => G [ 7 ] => H [ 8 ] => I [ 9 ] => J [ 10 ] => K [ 11 ] => L [ 12 ] => M [ 13 ] => N [ 14 ] => O [ 15 ] => P [ 16 ] => Q [ 17 ] => R [ 18 ] => S [ 19 ] => T [ 20 ] => U [ 21 ] => V [ 22 ] => W [ 23 ] => X [ 24 ] => Y [ 25 ] => Z ) Array ( [ 0 ] => z [ 1 ] => y [ 2 ] => x [ 3 ] => w [ 4 ] => v [ 5 ] => u [ 6 ] => t [ 7 ] => s [ 8 ] => r [ 9 ] => q [ 10 ] => p [ 11 ] => o [ 12 ] => n [ 13 ] => m [ 14 ] => l [ 15 ] => k [ 16 ] => j [ 17 ] => i [ 18 ] => h [ 19 ] => g [ 20 ] => f [ 21 ] => e [ 22 ] => d [ 23 ] => c [ 24 ] => b [ 25 ] => a )

4.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 )

三、数组的遍历：

1.foreach遍历：

foreach (array_expression as $value){}

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

闲话少说，上实例：

<? 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

 2.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> " ; ?>

运行结果：

姓名	性别	年龄
小张	男	24
小王	女	25
小李	男	23

3.for循环遍历：

 

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

运行结果：

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

四、数组的指针操作：

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

实例一：

 

<? 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

五、数组的增添删改操作：

1.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！

2.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。

六、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> " ; ?>

运行结果：

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"==="

七、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。

八、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！