PHP学习笔记-->006 PHP数组

数组能够在单独的变量名中存储一个或多个值。

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

---

数值数组-->数值数组存储的每个元素都带有一个数字 ID 键

eg:

$names = array("Peter","Quagmire","Joe");
$names[0] = "Peter";
$names[1] = "Quagmire";
$names[2] = "Joe";

<?php
$names[0] = "Peter";
$names[1] = "Quagmire";
$names[2] = "Joe";
echo $names[1] . " and " . $names[2] . " are ". $names[0] . "'s neighbors";
?>

输出：

Quagmire and Joe are Peter's neighbors

---

关联数组-->每个 ID 键都关联一个值

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

<?php
$ages['Peter'] = "32";
$ages['Quagmire'] = "30";
$ages['Joe'] = "34";
echo "Peter is " . $ages['Peter'] . " years old.";
?>

输出：

Peter is 32 years old.

---

多维数组-->多维数组中，主数组中的每个元素也是一个数组。在子数组中的每个元素也可以是数组，以此类推

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

如果输出这个数组的话，应该类似这样：

Array
(
[Griffin] => Array
  (
  [0] => Peter
  [1] => Lois
  [2] => Megan
  )
[Quagmire] => Array
  (
  [0] => Glenn
  )
[Brown] => Array
  (
  [0] => Cleveland
  [1] => Loretta
  [2] => Junior
  )
)

显示上面的数组中的一个单一的值：

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

输出：

Is Megan a part of the Griffin family?