Perl 中的 if_else 语句函数

Perl if语句后面可以跟随可选的else语句，该语句在布尔表达式为false时执行。

Perl if else - 语法

perl编程语言中if.else语句的语法是-

if(boolean_expression) {
   # statement(s) will execute if the given condition is true
} else {
   # statement(s) will execute if the given condition is false
}

Perl if else - 流程图

Perl if 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 following
   printf "a is less than 20\n";
} else { 
   # if condition is false then print the following
   printf "a is greater than 20\n";
}
print "value of a is : $a\n";

$a="";
# check the boolean condition using if statement
if( $a ) {
   # if condition is true then print the following
   printf "a has a true value\n";
} else {
   # if condition is false then print the following
   printf "a has a false value\n";
}
print "value of a is : $a\n";

执行上述代码时，将生成以下输出-

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a is greater than 20
value of a is : 100
a has a false value
value of a is :