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：

<?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 $... ] )

<?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:

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 )

<?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——

<?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：

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：

<?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：

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：

<?PHP 
$speed = array(50,120,180,240,380); 
foreach($speed as $keys=>$values){ 
echo $keys."=>".$values."<br />"; 
} 
?>

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

<?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	男	24
小王	女	25
小李	男	23

3.for循环遍历：

<?PHP 
$speed = range(0,220,20); 
for($i =0;$i<count($speed);$i++) { 
echo $speed[$i]." "; 
} 
?>

运行结果：

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