第五章 php数组操作_php基础

一．什么是数组
数组是一组有某种共同特性的元素，包括相似性和类型。
每个元素由一个特殊的标识符来区分，称之为key，而每个key都有一个value
1.创建数组的两种方式：
1.1 用array()函数

 <BR><?php <BR>$usernames = array ('Alerk', 'Mary', 'Lucy', 'Bob', 'Jack', 'John', 'Mark' ); <BR>foreach ( $usernames as $name ) <BR>{ <BR>echo $name . '<br />'; <BR>} <BR>?> <BR>

output
Alerk
Mary
Lucy

。本文来源gao!%daima.com搞$代*!码网1

搞代gaodaima码
Bob
Jack
John
Mark
1.2 用range()函数

 <BR><?php <BR>$numbers = range ( 0, 10 ); <BR>foreach ( $numbers as $num ) <BR>{ <BR>echo $num . '<br />'; <BR>} <BR>$letters = range ( 'a', 'z' ); <BR>foreach ( $letters as $letter ) <BR>{ <BR>echo $letter . '<br />'; <BR>} <BR>?> <BR>

output
0
1
2
3
4
5
6
7
8
9
10
a

c
d
e
f
g
h
i
j
k
l
m

q
r

t
u
v
w
x
y
z
2.循环访问数组元素的两种方式:
2.1 for循环

 <BR><?php <BR>//range的第三个参数表示步长 <BR>$numbers = range(1,10,2); <BR>for($i = 0;$i<count($numbers); $i ++) <BR>{ <BR>echo $numbers[$i].'<br />'; <BR>} <BR>?> <BR>

output
1
3
5
7
9
2.2 foreach循环

 <BR><?php <BR>$letters = range('a','h',2); <BR>foreach($letters as $letter) <BR>{ <BR>echo $letter.'<br />'; <BR>} <BR>?> <BR>

output
a
c
e
g
Foreach还可以用来输出数组的下标和对应的值

 <BR><?php <BR>$letters = range('a','g',2); <BR>foreach($letters as $key => $value) <BR>{ <BR>echo $key.'---'.$value.'<br />'; <BR>} <BR>?> <BR>

output
0—a
1—c
2—e
3—g
3.is_array()函数，用于变量判断是否为一个数组

 <BR><?php <BR>$numbers = range(1,10,2); <BR>if(is_array($numbers)) <BR>{ <BR>foreach($numbers as $num) <BR>{ <BR>echo $num.'<br />'; <BR>} <BR>} <BR>else <BR>{ <BR>echo $numbers; <BR>} <BR>?> <BR>

4.print_r函数，打印关于变量的易于理解的信息

 <BR><?php <BR>$usernames = array ('Jackie', 'Mary', 'Lucy', 'Bob', 'Mark', 'John' ); <BR>print_r ( $usernames ); <BR>?> <BR>

output
Array ( [0] => Jackie [1] => Mary [2] => Lucy [3] => Bob [4] => Mark [5] => John )
源代码里可以看到显示为：
Array
(
[0] => Jackie
[1] => Mary
[2] => Lucy
[3] => Bob
[4] => Mark
[5] => John
)
二．自定义键数组
1.如果不想创建默认下标为零的数组，可以用如下方法，创建键为字符串的数组

 <BR><?php <BR>//初始化数组 <BR>$userages = array('Jack'=> 23,'Lucy'=>25,'Mark'=>28); <BR>//访问数组各元素 <BR>echo $userages['Jack'].'<br />'; <BR>echo $userages['Lucy'].'<br />'; <BR>echo $userages['Mark'].'<br />'; <BR>?> <BR>

2.往自定义键数组里追加元素

 <BR><?php <BR>//初始化数组 <BR>$ages = array('Jack'=>23); <BR>//追加元素 <BR>$ages['Lucy']=25; <BR>$ages['Mark']=28; <BR>foreach($ages as $key => $value) <BR>{ <BR>echo $key.'----'.$value.'<br />'; <BR>} <BR>?> <BR>

3.直接添加元素，无需创建数组。

 <BR><?php <BR>//不创建数组直接添加 <BR>$ages['Jack']=23; <BR>$ages['Lucy']=25; <BR>$ages['Mark']=28; <BR>foreach($ages as $key => $value) <BR>{ <BR>echo $key.'----'.$value.'<br />'; <BR>} <BR>?> <BR>

4.循环打印数组foreach的使用

 <BR><?php <BR>$ages['Jack']=23; <BR>$ages['Lucy']=25; <BR>$ages['Mark']=28; <BR>foreach($ages as $key => $value) <BR>{ <BR>echo $key.'=>'.$value.'<br />'; <BR>} <BR>?> <BR>

5. each() — 返回数组中当前的键／值对并将数组指针向前移动一步

 <BR><?php <BR>$ages['Jack']=23; <BR>$ages['Lucy']=25; <BR>$ages['Mark']=28; <BR>$a = each($ages); <BR>print_r($a); <BR>echo '<br />'; <BR>$a = each($ages); <BR>print_r($a); <BR>echo '<br />'; <BR>$a = each($ages); <BR>print_r($a); <BR>?> <BR>

用each()函数做循环打印

 <BR><?php <BR>$ages['Jack']=23; <BR>$ages['Lucy']=25; <BR>$ages['Mark']=28; <BR>while(!! $element = each($ages)) <BR>{ <BR>print_r($element); <BR>echo '<br>'; <BR>} <BR>?> <BR>

另一种打印方式

 <BR><?php <BR>$ages['Jack']=23; <BR>$ages['Lucy']=25; <BR>$ages['Mark']=28; <BR>while(!! $element = each($ages)) <BR>{ <BR>echo $element['key'].'=>'.$element['value']; <BR>echo '<br>'; <BR>} <BR>?> <BR>

6.list()函数的使用–把数组中的值赋给一些变量

 <BR><?php <BR>$ages['Jack']=23; <BR>$ages['Lucy']=25; <BR>$ages['Mark']=28; <BR>list($name,$age)= each($ages); <BR>echo $name.'=>'.$age; <BR>?> <BR>

用list循环打印结果

 <BR><?php <BR>$ages['Jack']=23; <BR>$ages['Lucy']=25; <BR>$ages['Mark']=28; <BR>while(!!list($name,$age)= each($ages)) <BR>{ <BR>echo $name.'=>'.$age.'<br>'; <BR>} <BR>?> <BR>

output
Jack=>23
Lucy=>25
Mark=>28
7.reset()函数的使用–将数组的内部指针指向第一个单元

 <BR><?php <BR>$ages['Jack']=23; <BR>$ages['Lucy']=25; <BR>$ages['Mark']=28; <BR>each($ages); <BR>each($ages); <BR>list($name,$age)= each($ages); <BR>echo $name.'=>'.$age.'<br>'; <BR>//把数组重新设定到数组开始处 <BR>reset($ages); <BR>list($name,$age)= each($ages); <BR>echo $name.'=>'.$age.'<br>'; <BR>?> <BR>

Output
Mark=>28
Jack=>23
8. array_unique() — 移除数组中重复的值

 <BR><?php <BR>$nums = array(1,2,3,4,5,6,5,4,3,2,1,1,2,3,4,5,6); <BR>//返回一个不包含重复值的数组 <BR>$result = array_unique($nums); <BR>print_r($result); <BR>?> <BR>Output <BR>Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 ) <BR>9. array_flip ()-- 交换数组中的键和值 <BR><?php <BR>$userages = array('Jack'=> 23,'Lucy'=>25,'Mark'=>28); <BR>$ages = array_flip($userages); <BR>print_r($ages); <BR>?> <BR>

output
Array ( [23] => Jack [25] => Lucy [28] => Mark )
三．数组里的数组
数组里不一定就是一个关键字和值的列表，数组里也可以放入数组

 <BR><?php <BR>$produces = array( <BR>array('apple',6,28.8), <BR>array('pear',3,15.6), <BR>array('banana',10,4.6) <BR>); <BR>echo $produces[0][0].'|'.$produces[0][1].'|'.$produces[0][2].'<br>'; <BR>echo $produces[1][0].'|'.$produces[1][1].'|'.$produces[1][2].'<br>'; <BR>echo $produces[2][0].'|'.$produces[2][1].'|'.$produces[2][2].'<br>'; <BR>?> <BR>

output
apple|6|28.8
pear|3|15.6
banana|10|4.6
用for循环打印数组中的数组

 <BR><?php <BR>$produces = array ( <BR>array ('apple', 6, 28.8 ), <BR>array ('pear', 3, 15.6 ), <BR>array ('banana', 10, 4.6 ) <BR>); <BR>for($i = 0; $i < count ( $produces ); $i ++) <BR>{ <BR>for($j = 0; $j < count ( $produces [$i] ); $j ++) <BR>{ <BR>echo '|' . $produces[$i][$j]; <BR>} <BR>echo '<br>'; <BR>} <BR>?> <BR>

output
|apple|6|28.8
|pear|3|15.6
|banana|10|4.6
二维数组

 <BR><?php <BR>$produces = array ( <BR>array ('name' => 'apple', 'amount' => 6, 'price' => 28.8 ), <BR>array ('name' => 'pear', 'amount' => 3, 'price' => 15.6 ), <BR>array ('name' => 'banana', 'amount' => 10, 'price' => 4.6 ) <BR>); <BR>while(!!List($key,$value)=each($produces)) <BR>{ <BR>while(!!list($key2,$value2)=each($value)) <BR>{ <BR>echo '|'.$key2.'=>'.$value2; <BR>} <BR>echo '<br>'; <BR>} <BR>?> <BR>

 <BR><?php <BR>$produces = array ( <BR>array ('name' => 'apple', 'amount' => 6, 'price' => 28.8 ), <BR>array ('name' => 'pear', 'amount' => 3, 'price' => 15.6 ), <BR>array ('name' => 'banana', 'amount' => 10, 'price' => 4.6 ) <BR>); <BR>foreach($produces as $key1 => $value1) <BR>{ <BR>foreach($value1 as $key2 => $value2) <BR>{ <BR>echo '|'.$key2.'=>'.$value2; <BR>} <BR>echo '<br>'; <BR>} <BR>?> <BR>

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array('lemo','banana','apple','pear'); <BR>echo '原始的数组：'; <BR>print_r($fruits); <BR>echo '<br />'; <BR>sort($fruits); <BR>echo '排序后的数组：'; <BR>print_r($fruits); <BR>?> <BR>

output
原始的数组：Array ( [0] => lemo [1] => banana [2] => apple [3] => pear )
排序后的数组：Array ( [0] => apple [1] => banana [2] => lemo [3] => pear )
2.Sort()函数对中文的排序

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array('柠檬','香蕉','苹果','梨子'); <BR>echo '原始的数组：'; <BR>print_r($fruits); <BR>echo '<br />'; <BR>sort($fruits); <BR>echo '排序后的数组：'; <BR>print_r($fruits); <BR>?> <BR>

Output:
原始的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 )
排序后的数组：Array ( [0] => 柠檬 [1] => 梨子 [2] => 苹果 [3] => 香蕉 )
3. asort — 对数组进行排序并保持索引关系

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array('a'=>'柠檬','b'=>'香蕉','c'=>'苹果','d'=>'梨子'); <BR>echo '原始的数组：'; <BR>print_r($fruits); <BR>echo '<br />'; <BR>asort($fruits); <BR>echo '排序后的数组：'; <BR>print_r($fruits); <BR>?> <BR>

output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
排序后的数组：Array ( [a] => 柠檬 [d] => 梨子 [c] => 苹果 [b] => 香蕉 )
4. ksort — 对数组按照键名排序

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array('b'=>'柠檬','a'=>'香蕉','d'=>'苹果','c'=>'梨子'); <BR>echo '原始的数组：'; <BR>print_r($fruits); <BR>echo '<br />'; <BR>ksort($fruits); <BR>echo '排序后的数组：'; <BR>print_r($fruits); <BR>?> <BR>

output
原始的数组：Array ( [b] => 柠檬 [a] => 香蕉 [d] => 苹果 [c] => 梨子 )
排序后的数组：Array ( [a] => 香蕉 [b] => 柠檬 [c] => 梨子 [d] => 苹果 )
5. rsort — 对数组逆向排序

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array('柠檬','香蕉','苹果','梨子'); <BR>echo '原始的数组：'; <BR>print_r($fruits); <BR>echo '<br />'; <BR>rsort($fruits); <BR>echo '排序后的数组：'; <BR>print_r($fruits); <BR>?> <BR>

output
原始的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 )
排序后的数组：Array ( [0] => 香蕉 [1] => 苹果 [2] => 梨子 [3] => 柠檬 )
6. arsort — 对数组进行逆向排序并保持索引关系

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array('a'=>'柠檬','b'=>'香蕉','c'=>'苹果','d'=>'梨子'); <BR>echo '原始的数组：'; <BR>print_r($fruits); <BR>echo '<br />'; <BR>arsort($fruits); <BR>echo '排序后的数组：'; <BR>print_r($fruits); <BR>?> <BR>

output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
排序后的数组：Array ( [b] => 香蕉 [c] => 苹果 [d] => 梨子 [a] => 柠檬 )
7. krsort — 对数组按照键名逆向排序

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array('a'=>'柠檬','b'=>'香蕉','c'=>'苹果','d'=>'梨子'); <BR>echo '原始的数组：'; <BR>print_r($fruits); <BR>echo '<br />'; <BR>krsort($fruits); <BR>echo '排序后的数组：'; <BR>print_r($fruits); <BR>?> <BR>

output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
排序后的数组：Array ( [d] => 梨子 [c] => 苹果 [b] => 香蕉 [a] => 柠檬 )
8. shuffle — 将数组打乱

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array('a'=>'柠檬','b'=>'香蕉','c'=>'苹果','d'=>'梨子'); <BR>echo '原始的数组：'; <BR>print_r($fruits); <BR>echo '<br />'; <BR>shuffle($fruits); <BR>echo '打乱后的数组：'; <BR>print_r($fruits); <BR>?> <BR>

output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
打乱后的数组：Array ( [0] => 香蕉 [1] => 苹果 [2] => 柠檬 [3] => 梨子 )
9. array_reverse — 返回一个单元顺序相反的数组

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array('a'=>'柠檬','b'=>'香蕉','c'=>'苹果','d'=>'梨子'); <BR>echo '原始的数组：'; <BR>print_r($fruits); <BR>echo '<br />'; <BR>$fruits = array_reverse($fruits); <BR>echo '反转后的数组：'; <BR>print_r($fruits); <BR>?> <BR>

output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
反转后的数组：Array ( [d] => 梨子 [c] => 苹果 [b] => 香蕉 [a] => 柠檬 )
10. array_unshift — 在数组开头插入一个或多个单元

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array('a'=>'柠檬','b'=>'香蕉','c'=>'苹果','d'=>'梨子'); <BR>echo '原始的数组：'; <BR>print_r($fruits); <BR>echo '<br />'; <BR>array_unshift($fruits,'杮子'); <BR>echo '插入后的数组：'; <BR>print_r($fruits); <BR>?> <BR>

output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
插入后的数组：Array ( [0] => 杮子 [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
11. array_shift — 将数组开头的单元移出数组

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array('a'=>'柠檬','b'=>'香蕉','c'=>'苹果','d'=>'梨子'); <BR>echo '原始的数组：'; <BR>print_r($fruits); <BR>echo '<br />'; <BR>array_shift($fruits); <BR>echo '移出后的数组：'; <BR>print_r($fruits); <BR>?> <BR>

output
原始的数组：Array ( [a] => 柠檬 [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
移出后的数组：Array ( [b] => 香蕉 [c] => 苹果 [d] => 梨子 )
12. array_rand — 从数组中随机取出一个或多个单元

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array ('柠檬', '香蕉', '苹果', '梨子' ); <BR>echo '原始的数组：'; <BR>print_r ( $fruits ); <BR>echo '<br />'; <BR>$newArr_key = array_rand ( $fruits, 2 ); <BR>echo '随机后的数组：'; <BR>echo $fruits [$newArr_key [0]].' '; <BR>echo $fruits [$newArr_key [1]]; <BR>?> <BR>

output
原始的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 )
随机后的数组：梨子苹果
13. array_pop — 将数组最后一个单元弹出（出栈）

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array ('柠檬', '香蕉', '苹果', '梨子' ); <BR>echo '原始的数组：'; <BR>print_r ( $fruits ); <BR>echo '<br />'; <BR>array_pop ( $fruits ); <BR>echo '弹出后的数组：'; <BR>print_r ( $fruits ); <BR>?> <BR>

Output:
原始的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 )
弹出后的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 )
14. array_push — 将一个或多个单元压入数组的末尾（入栈）

 <BR><meta http-equiv="content-type" content="text/html;charset=utf-8" /> <BR><?php <BR>$fruits = array ('柠檬', '香蕉', '苹果', '梨子' ); <BR>echo '原始的数组：'; <BR>print_r ( $fruits ); <BR>echo '<br />'; <BR>array_push ( $fruits,'杮子'); <BR>echo '弹出后的数组：'; <BR>print_r ( $fruits ); <BR>?> <BR>

Output:
原始的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 )
弹出后的数组：Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 [4] => 杮子 )
五．数组的指针的操作
each — 返回数组中当前的键／值对并将数组指针向前移动一步
current — 返回数组中的当前单元
reset — 将数组的内部指针指向第一个单元
end — 将数组的内部指针指向最后一个单元
next — 将数组中的内部指针向前移动一位
pos — current() 的别名
prev — 将数组的内部指针倒回一位
<meta http-equiv=”content-type” content=”text/html;charset=utf-8″ />

 <BR><?php <BR>$fruits = array ('柠檬', '香蕉', '苹果', '梨子' ); <BR>print_r ( $fruits ); <BR>echo '<br />'; <BR>echo 'each() : '; <BR>print_r ( each ( $fruits ) ); <BR>echo '<br />'; <BR>echo 'current() : '; <BR>echo (current ( $fruits )); <BR>echo '<br />'; <BR>echo 'next() : '; <BR>echo (next ( $fruits )); <BR>echo '<br />'; <BR>echo 'end() : '; <BR>echo (end ( $fruits )); <BR>echo '<br />'; <BR>echo 'prev() : '; <BR>echo (prev ( $fruits )); <BR>echo '<br />'; <BR>echo 'pos() : '; <BR>echo (pos ( $fruits )); <BR>echo '<br />'; <BR>?> <BR>

Output:
Array ( [0] => 柠檬 [1] => 香蕉 [2] => 苹果 [3] => 梨子 )
each() : Array ( [1] => 柠檬 [value] => 柠檬 [0] => 0 [key] => 0 )
current() : 香蕉
next() : 苹果
end() : 梨子
prev() : 苹果
pos() : 苹果
六．统计数组个数
count — 计算数组中的单元数目或对象中的属性个数
sizeof — count() 的别名
array_count_values — 统计数组中所有的值出现的次数

 <BR><?php <BR>$nums = array (1, 3, 5, 1, 3, 4, 5, 65, 4, 2, 2, 1, 4, 4, 1, 1, 4, 1, 5, 4, 5, 4 ); <BR>echo count ( $nums ); <BR>echo '<br>'; <BR>echo sizeof ( $nums ); <BR>echo '<br>'; <BR>$arrayCount = array_count_values ( $nums ); <BR>print_r ( $arrayCount ); <BR>?> <BR>

output
22
22
Array ( [1] => 6 [3] => 2 [5] => 4 [4] => 7 [65] => 1 [2] => 2 )
七．将数组转换成标量变量：extract()
把数组中的每个元素转换成变量，变量名是数组元素的key,变量值为数组元素的value.

 <BR><?php <BR>$fruits = array('a'=>'apple','b'=>'banana','o'=>'orange'); <BR>extract($fruits); <BR>echo $a.'<br>'; <BR>echo $b.'<br>'; <BR>echo $o.'<br>'; <BR>?> <BR>

output
apple
banana
orange

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