条件语句

Perl当然也支持if/then/else语句，下面是一个例子：

if ($a)
{
	print "The string is not empty\n";
}
else
{
	print "The string is empty\n";
}

记住，空字符串被认为是false，如果$a是字符串"0"，结果将是"empty"。

条件语句中也可以使用elsif：

if (!$a)			# The ! is the not operator
{
	print "The string is empty\n";
}
elsif (length($a) == 1)		# If above fails, try this
{
	print "The string has one character\n";
}
elsif (length($a) == 2)		# If that fails, try this
{
	print "The string has two characters\n";
}
else				# Now, everything has failed
{
	print "The string has lots of characters\n";
}

注意：elsif中确实缺一个"e"。