How to use "*" Quantifier in Regular Expression.
Quantifier "*" in Regular Expression?
Explanation
The "*" quantifier is used to know the number of times a character or a sequence preceding "*" may occur at least zero or more times.It just matches any number of occurence or even if does'nt occur.
For example if we have a pattern "lt*" it matches the string that has the letter "l" followed by zero or more number of "t" as it is the preceding character to the quantifier "*". So the string matched would be "l","ltt","later" etc.
<?php
$name = "bcd";
if (preg_match("/a(bcd)*/", $name))
{echo "Pattern matches!";}
else
{echo "Pattern not matched!";}
?> Result :
Pattern not matched!
In the above example the possible matches are "a", "abcd", "abcdbcd" etc. Here "bcd" is grouped using a "()" to match zero or more times.
#! C:programfilesperlbinperl
print "content-type: text/htmlnn";
if ("laaer" =~ m/lt*/)
{
print "The pattern matched.!n";
}
else
{
print "The pattern not found!n";
} Result :
The pattern matched.!
In the above example's the pattern "lt*" means the string should start with "l" with a following "t" or even can be without a "t" ie., so the string "laaer" is matched.
For example if we have a pattern "lt*" it matches the string that has the letter "l" followed by zero or more number of "t" as it is the preceding character to the quantifier "*". So the string matched would be "l","ltt","later" etc.
PHP Example:
<?php
$name = "bcd";
if (preg_match("/a(bcd)*/", $name))
{echo "Pattern matches!";}
else
{echo "Pattern not matched!";}
?>
Pattern not matched!
In the above example the possible matches are "a", "abcd", "abcdbcd" etc. Here "bcd" is grouped using a "()" to match zero or more times.
Perl Example:
#! C:programfilesperlbinperl
print "content-type: text/htmlnn";
if ("laaer" =~ m/lt*/)
{
print "The pattern matched.!n";
}
else
{
print "The pattern not found!n";
}
The pattern matched.!
In the above example's the pattern "lt*" means the string should start with "l" with a following "t" or even can be without a "t" ie., so the string "laaer" is matched.
