Regular expression for limiting character not working - php

Question

I want to limit the number of "b" between 1 and 6, for which I'm using the following code:
<?php
$str="Big black books being kept in a black bag of a beautiful babe";
$pattern="/(b){1,6}/";
if(!preg_match($pattern,$str,$matches))
{
echo "Please use six bs";
}else
{/*do nothing*/}
print_r($matches);
?>
But It's not working. What am I doing wrong?

Answer 1

Through regex alone..
$str="Big black books being kept in a black bag of a beautiful babe";
$pattern="/^([^b]*b){1,6}[^b]*$/";
if(!preg_match($pattern,$str,$matches))
{
echo "Please use upto six bs";
}else
{/*do nothing*/}
print_r($matches);
and note that this must except atleast one single b. If you want to match also the line which don't have any single b then use /^([^b]*b){0,6}[^b]*$/
Add case-insensitive modifier i if you want to count also for capital B's.
Explanation:
^ start of the line.
([^b]*b){1,6} It matches (zero or more non-b characters and a b)(from 1 to 6 times). So this ensures that there must be character b exists min of 1 time and a max of 6 times.
[^b]* Matches any char but not of b, zero or more times. This ensures that there are no more further b exists.
$ End of the line boundary..

Answer 2

Try using match count.
<?php
$str="Big black books being kept in a black bag of a beautiful babe";
preg_match_all("/(b)/i",$str,$matches);
if(isset($matches[1]) && count($matches[1]) > 6 )
{
echo "Please use six bs";
}else
{/*do nothing*/}
print_r($matches);
?>

Answer 3

I think you want to count the number of Bs in the whole string while your regular expression counts them only in rows. i.e. "bbb" or just "b" would return a match.
Try using substr_count to achieve what I think you want. Here's an example.
<?php
$str = "Big black books being kept in a black bag of a beautiful babe";
if(substr_count($str, "b") > 6)
echo "Six is the limit...";
else
echo "Doing nothing...";
?>
But of course, it won't really help if you want to see the found matches.