# Perl 中的`unless-else`语句 > 原文： [https://beginnersbook.com/2017/02/unless-else-statement-in-perl/](https://beginnersbook.com/2017/02/unless-else-statement-in-perl/) 类似于[`unless`语句](https://beginnersbook.com/2017/02/unless-statement-in-perl/)，Perl 中的`unless-else`语句与[`if-else`语句](https://beginnersbook.com/2017/02/if-else-statement-in-perl/)相反。在`except-else`中，如果条件为`false`，执行内部语句，如果条件为`true`，则执行`else`内的语句。 ```perl unless(condition) { #These statements would execute #if the condition is false. statement(s); } else { #These statements would execute #if the condition is true. statement(s); } ``` #### 例 ```perl #!/usr/local/bin/perl printf "Enter any number:"; $num = <STDIN>; unless($num>=100) { #This print statement would execute, #if the given condition is false printf "num is less than 100\n"; } else { #This print statement would execute, #if the given condition is true printf "number is greater than or equal to 100\n"; } ``` **输出：** ```perl Enter any number:100 number is greater than or equal to 100 ```