Regex Tutorial - Non Word Boundry in Regular Expression.

Topic

What is Non Word Boundry?

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Explanation

A non-word boundry is the boundry between the word characters that should be always between the characters [a-zA-Z0-9]it give an unmatch if other characters are used.

    string = "hiox"
    "/io\B/" - Match boundry between "io" and "x".
    "/ox\B/" - Unmatch as its nonword boundry between "ox", """.

PHP Example:

    <?php
    $name = "sampaulchristdany";
    if (preg_match("/sam\B/", $name))
     echo "Pattern matches!";
    else 
     echo "Pattern not matched!";
    ?>

Result:

    Pattern matches!

In the above example the word "sam" and the next word "paul" is matched,as both are word characters.

Perl Example:

    #! C:\programfiles\perl\bin\perl
    print "content-type: text/html\n\n";
    $name= "sam-paul-christ-dany";
    if ($name =~ m/sam\Bpaul/) 
      {print "The name format matched!";} 
    else 
      {print "The name format not matched!";}

Result:

    The name format not matched!

In the above example the pattern "sam\Bpaul" does not match since the word boundry is found for the word "sam" and "-" which is not word character.

Non Word Boundry "\B" metacharacter in Regular Expression.