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if 语句后可以跟可选的 elsif ... else 语句，这对于使用单个if ... elsif语句测试各种条件非常有用。

if...elsif...else - 语法

Perl编程语言中的 if ... elsif...else语句的语法是-

if(boolean_expression 1) {# Executes when the boolean expression 1 is true
} elsif( boolean_expression 2) {# Executes when the boolean expression 2 is true
} elsif( boolean_expression 3) {# Executes when the boolean expression 3 is true
} else {# Executes when the none of the above condition is true
}

if...elsif...else - 示例

#!/usr/local/bin/perl$a=100;
# check the boolean condition using if statement
if( $a  ==  20 ) {# if condition is true then print the followingprintf "a has a value which is 20\n";
} elsif( $a ==  30 ) {# if condition is true then print the followingprintf "a has a value which is 30\n";
} else {# if none of the above conditions is trueprintf "a has a value which is $a\n";
}

在这里，我们使用等于运算符==，用于检查两个操作数是否相等。如果两个操作数相同，则返回true，否则返回false。

a has a value which is 100

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