php中的有:运算符吗?

swingcoder

如

1. 
   
2. if ( !in_array('Snoopy', get_declared_classes() ) ) :
   
3. ....
   
4. endif;
   

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表示什么意思,好像跟?:表达式不同??!!

另外,谁知道__()函数是怎么使用的,跟普通函数一样?有版本限制?
谢谢

[ 本帖最后由 swingcoder 于 2006-2-8 18:04 编辑 ]

dz902

这应该是表达式的不同的表示方法吧，不是很常用，比如：

1. 
   
2. if (a==1):
   
3.     //something
   
4. endif;
   

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详见：http://www.php.net/manual/en/control-structures.alternative-syntax.php

xuzuning

in_array('Snoopy', get_declared_classes() )中
get_declared_classes()返回以定义的类（数组）
in_array函数检查第一个参数是否在第二个参数（数组）中，成功返回真

__xxxxx()为php类的预定义方法，由于没有出现在手册的函数列表中，你需要通过手册中的“搜索”功能找到他们

swingcoder

原帖由 dz902 于 2006-2-8 22:55 发表
这应该是表达式的不同的表示方法吧，不是很常用，比如：

1. 
   
2. if (a==1):
   
3.     //something
   
4. endif;
   

复制代码

详见：http://www.php.net/manual/en/control-structures.alternative-syntax.php

奇怪,今天怎么上不了php.net

swingcoder

Alternative syntax for control structures
PHP offers an alternative syntax for some of its control structures; namely, if, while, for, foreach, and switch. In each case, the basic form of the alternate syntax is to change the opening brace to a colon ( and the closing brace to endif;, endwhile;, endfor;, endforeach;, or endswitch;, respectively.


<?php if ($a == 5): ?>
A is equal to 5
<?php endif; ?>  



In the above example, the HTML block "A is equal to 5" is nested within an if statement written in the alternative syntax. The HTML block would be displayed only if $a is equal to 5.

The alternative syntax applies to else and elseif as well. The following is an if structure with elseif and else in the alternative format:


<?php
if ($a == 5):
   echo "a equals 5";
   echo "...";
elseif ($a == 6):
   echo "a equals 6";
   echo "!!!";
else:
   echo "a is neither 5 nor 6";
endif;
?>  



See also while, for, and if for further examples.