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php笔记之:php函数range() round()和list()的使用说明

Jun 13, 2016 am 11:53 AM
list php range round one Instructions for use function create and fast array of notes

一>>

range()函数快速创建数组的简单方法,使用low到high范围的整数值填充数组,函数将返回一个包含次范围内所有整数的数组.形式如下

array range(int low,int high[,int step])

典型用法如下

例子:建立1-6的6个数字的数组(骰子)

$die = range(0,6);

建立0-30所有双数的数组

$even  = (0,20,2);//步长为2

这个函数不仅仅可以用作数字,还可以用作字母.

$words = range('A','Z');

将建立包含A到Z的的所有字母的数组.此处可以用于生成验证码函数.

二>>

round()函数

这个函数是怕我记混淆了.这个函数和上面的哪个range()是天壤之别.

这个函数的作用是

取浮点数的精度

float round(float var[,int preisin})

典型用法

例: $pi = 3.141592653;

round($pi,4);

echo $pi;

将输出 3.1415

三>>

list()函数

list()函数可以在一次操作中从一个数组内提取多个值.同时为变量赋值.形式如下

void list(mixed)

典型用法

<code><code>
<p class="codetitle"><span style="CURSOR: pointer" onclick="doCopy('code98313')"><u>复制代码</u></span> 代码如下:</p> <p class="codebody" id="code98313"><br><?php <br><br>$info = array('coffee', 'brown', 'caffeine'); <br><br>// Listing all the variables <br>list($drink, $color, $power) = $info; <br>echo "$drink is $color and $power makes it special.\n"; <br><br>// Listing some of them <br>list($drink, , $power) = $info; <br>echo "$drink has $power.\n"; <br><br>// Or let's skip to only the third one <br>list( , , $power) = $info; <br>echo "I need $power!\n"; <br><br>?> <br></p> <br>
<code><span style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #000000"><span style="FONT-FAMILY: Courier New"><span style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #0000bb">上例摘自PHP手册</span></span></span>
<code><span style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #000000"><span style="FONT-FAMILY: Courier New"><span style="FONT-FAMILY: 宋体; COLOR: #0000bb">可以用list()配合正则来切割字符串存入变量表</span></span></span>
<code><span style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #000000"><span style="COLOR: #0000bb">典型用法</span></span>
 
<code><span style="LINE-HEIGHT: 1.5; FONT-FAMILY: 宋体, Verdana, Arial, Helvetica, sans-serif; COLOR: #000000"><strong><span style="COLOR: #0000bb">list($name,$occupation,$color) = exolode("|",$line);</span> <br></strong></span>
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