Beefy Boxes and Bandwidth Generously Provided by pair Networks
Clear questions and runnable code
get the best and fastest answer
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
Another useful thing would be able to match a certain number of characters that matched a certain criteria. There are two types of searches you can do when you're dealing with quantifiers: greedy or nongreedy, or in other terms maximal, and minimal. A maximal or greedy search tries to match as many characters as it can while still returning a true value. So if we were looking for 1 to 4 b's in a row and had a string with 3 b's in a row we would match the 3 b's. If it was a minimal or nongreedy search only the first b would be matched.

Here's a table that sums up quantifiers.

GreedyNongreedyAllowed numbers for a match
???0 or 1 time
++?1 or more times
**?0 or more times
{i}{i}?exactly i times
{i,}{i,}?i or more times
{i,j}{i,j}?at lease i times and at most j times


Obviously Perl needs to know what these quantifiers are referring to. The quantifier is associated with the character directly to its left unless parentheses are used for grouping.

/b{3}/ #matches three b's /(ha){3}/ #matches hahaha
Onto Character Class Abbreviations

In reply to Quantifiers in regular expressions by root

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • Outside of code tags, you may need to use entities for some characters:
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others surveying the Monastery: (6)
    As of 2014-07-13 06:22 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      When choosing user names for websites, I prefer to use:








      Results (247 votes), past polls