PHP学习随笔(3):数组

三种数组类型:

　　1.数值数组:带有数字id键的数组

　　2.关联数组:数组中的每个id键关联一个值

　　3.多维数组:包含一个或多个数组的数组

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数值数组

　　数值数组存储的每个元素有带有一个数字id键(索引?)

　　创建数值数组的两种方法:

$names = array("Peter","Quagmire","Joe");

$names[0] = "Peter";
$names[1] = "Quagmire";
$names[2] = "Joe";

　　以上代码都可以创建数值数组,下面是在脚本中使用这些id

<?php

$names[0] = "Peter";
$names[1] = "Quagmire";
$names[2] = "Joe";

echo $names[1] . " and " . $names[2] . " are ". $names[0] . "'s neighbors";
?>

　　输出结果:

Quagmire and Joe are Peter's neighbors

关联数组

　　通过关联数组,我们可以把值作为键,并向它们赋值(类似于C#中的字典集合)

　　下面为关联数组的创建方法

$ages = array("Peter"=>32, "Quagmire"=>30, "Joe"=>34);

$ages['Peter'] = "32";
$ages['Quagmire'] = "30";
$ages['Joe'] = "34";

　　在脚本中使用

<?php

$ages['Peter'] = "32";
$ages['Quagmire'] = "30";
$ages['Joe'] = "34";

echo "Peter is " . $ages['Peter'] . " years old.";
?>

　　输出结果

Peter is 32 years old.

多维数组

　　在多维数组中,每个元素的值都是一个数组,以次类推

$families = array
(
  "Griffin"=>array
  (
  "Peter",
  "Lois",
  "Megan"
  ),
  "Quagmire"=>array
  (
  "Glenn"
  ),
  "Brown"=>array
  (
  "Cleveland",
  "Loretta",
  "Junior"
  )
);

　　输出一个值

echo "Is " . $families['Griffin'][2] . 
" a part of the Griffin family?"; 

　　输出结果

Is Megan a part of the Griffin family?