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{php数组}

时间:2021-07-01 10:21:17 帮助过:5人阅读

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:

              

" 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 $... ] )  

              

      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 )

              

      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??

              

" ; $array2 = range ( " A " , " Z " ); print_r ( $array2 ); echo "
" ; $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:

              

" ; print_r ( $arrayFilled ); echo "

" ; $keys = array ( " string " , " 2 " , 9 , " SDK " , " PK " ); $array2 = array_fill_keys( $keys , " testing " ); 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)



  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:

               

$values ){ echo $keys . " => " . $values . "
" ; } ?>

    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

              

" ; while ( list ( $keys , $value ) = each ( $staff )){ list ( $name , $sex , $age ) = $value ; echo " $name $sex $age " ; } echo " " ; ?>

    运行结果:
姓名 性别 年龄
小张 24
小王 25
小李 23
    3.for循环遍历:

               

    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:

                

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 "
" ; echo prev ( $speed ); // 输出前一位置数组值 echo "
" ; echo reset ( $speed ); // 重置数组的指针,将指针指向起始位置 echo "
" ; echo end ( $speed ); // 输出最后位置的数组值 echo "
" ; ?>

    运行结果:

              

0220 200 0 220

实例二:each函数指针操作

              

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

    运行结果:

              

each实现指针下移 0挡的速度是01挡的速度是402挡的速度是803挡的速度是1204挡的速度是1605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:

               

80 , 2 => 120 , 3 => 160 ); echo " 使用表达式添加数组成员
" ; $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

              

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
" ; print_r ( $num ); echo "
array_pad 还可以填充数组首部
" ; $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):

              

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

              

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:

                

" ; unset ( $num [ 4 ]); print_r ( $num ); echo "
" ; 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

              

实例三:array_unique删除数组中的重复值:

              

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

              

" 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         "    
" ; ?>

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

              

运行结果:

数组中存在


实例二:key()取得数组当前的键名:

              

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:

              

" ; while ( list ( $keys , $value ) = each ( $staff )){ list ( $name , $sex , $age ) = $value ; echo " $name $sex $age " ; } echo " " ; ?>

运行结果:

实例四:array_flip()交换数组的键值和值:

              

" ; $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:

              

" ; $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:

              

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:

              

" ; 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:

               

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:

               

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();

              

" ; 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():

              

" 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!

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