PHP之数组学习

  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:

  

复制代码 代码如下:

  <?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 $... ] )  

  

复制代码 代码如下:

  <?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:

  

复制代码 代码如下:

  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 )

  

复制代码 代码如下:

  <?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——

  

复制代码 代码如下:

  <?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:

  

复制代码 代码如下:

  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:

  

复制代码 代码如下:

  <?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:

  

复制代码 代码如下:

  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

  )

  二、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:

  

复制代码 代码如下:

  <?PHP

  $speed = array(50,120,180,240,380);

  foreach($speed as $keys=>$values){

  echo $keys."=>".$values."<br />";

  }

  ?>

  运行结果:

  

复制代码 代码如下:

  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

  

复制代码 代码如下:

  <?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 24
小王 25
小李 23
3.for循环遍历:

  

复制代码 代码如下:

  <?PHP

  $speed = range(0,220,20);

  for($i =0;$i<count($speed);$i++) {

  echo $speed[$i]." ";

  }

  ?>

  运行结果:

  

复制代码 代码如下:

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