Beefy Boxes and Bandwidth Generously Provided by pair Networks
Welcome to the Monastery
 
PerlMonks  

comment on

( [id://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":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

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

How do I use this?Last hourOther CB clients
Other Users?
Others making s'mores by the fire in the courtyard of the Monastery: (4)
As of 2024-04-25 07:20 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found