Smarty的{if}条件判断和PHP的if
非常相似，只是增加了一些特性。
每个{if}必须有一个配对的{/if}.
也可以使用{else} 和
{elseif}. 全部的PHP条件表达式和函数都可以在if内使用，如||, or,
&&, and,
is_array(), 等等.
如果开启了安全机制，那么只有在$php_functions设置允许的PHP函数才能使用。
参见安全机制。
下面是可用的运算符列表，使用中都会放到元素的中间并且用空格分隔。 注意列表中[方括号]的是可选的，而且还会列出对应PHP的表达式。
| 运算符 | 别名 | 语法示例 | 含义 | 对应PHP语法 |
|---|---|---|---|---|
| == | eq | $a eq $b | 等于 | == |
| != | ne, neq | $a neq $b | 不等于 | != |
| > | gt | $a gt $b | 大于 | > |
| < | lt | $a lt $b | 小于 | < |
| >= | gte, ge | $a ge $b | 大于等于 | >= |
| <= | lte, le | $a le $b | 小于等于 | <= |
| === | $a === 0 | 绝对等于 | === | |
| ! | not | not $a | 非 (一元运算) | ! |
| % | mod | $a mod $b | 取模 | % |
| is [not] div by | $a is not div by 4 | 取模为0 | $a % $b == 0 | |
| is [not] even | $a is not even | [非] 取模为0 (一元运算) | $a % 2 == 0 | |
| is [not] even by | $a is not even by $b | 水平分组 [非] 平均 | ($a / $b) % 2 == 0 | |
| is [not] odd | $a is not odd | [非] 奇数 (一元运算) | $a % 2 != 0 | |
| is [not] odd by | $a is not odd by $b | [非] 奇数分组 | ($a / $b) % 2 != 0 |
Example 7.44. {if} 表达式
{if $name eq 'Fred'}
Welcome Sir.
{elseif $name eq 'Wilma'}
Welcome Ma'am.
{else}
Welcome, whatever you are.
{/if}
{* an example with "or" logic *}
{if $name eq 'Fred' or $name eq 'Wilma'}
...
{/if}
{* same as above *}
{if $name == 'Fred' || $name == 'Wilma'}
...
{/if}
{* parenthesis are allowed *}
{if ( $amount < 0 or $amount > 1000 ) and $volume >= #minVolAmt#}
...
{/if}
{* you can also embed php function calls *}
{if count($var) gt 0}
...
{/if}
{* check for array. *}
{if is_array($foo) }
.....
{/if}
{* check for not null. *}
{if isset($foo) }
.....
{/if}
{* test if values are even or odd *}
{if $var is even}
...
{/if}
{if $var is odd}
...
{/if}
{if $var is not odd}
...
{/if}
{* test if var is divisible by 4 *}
{if $var is div by 4}
...
{/if}
{*
test if var is even, grouped by two. i.e.,
0=even, 1=even, 2=odd, 3=odd, 4=even, 5=even, etc.
*}
{if $var is even by 2}
...
{/if}
{* 0=even, 1=even, 2=even, 3=odd, 4=odd, 5=odd, etc. *}
{if $var is even by 3}
...
{/if}
Example 7.45. {if} 的更多例子
{if isset($name) && $name == 'Blog'}
{* do something *}
{elseif $name == $foo}
{* do something *}
{/if}
{if is_array($foo) && count($foo) > 0}
{* do a foreach loop *}
{/if}