DZone Snippets: regexp code

Javascript count line breaks

featurelover (Jochen Preusche) — Tue, 15 Jul 2008 08:57:23 GMT

Returns the number of line breaks in a string.



function lineBreakCount(str){

	/* counts \n */

	try {

		return((str.match(/[^\n]*\n[^\n]*/gi).length));

	} catch(e) {

		return 0;

	}

}

Rewrite input to friendly URL

milkshake (milkshake) — Tue, 10 Jun 2008 20:30:06 GMT

// Take an input and rewrite it to a friendly-url-like-this

Extract the filename from a URL

jrobertson (James Robertson) — Sun, 20 Apr 2008 15:24:54 GMT

This ECMAScript extracts the filename from a URL. eg. the filename 'index4.svg' would be extracted from the document.URL with the value 'http://rorbuilder.info/r/whiteboardqueue/index4.svg'.



var regexp = /(\w|[-.])+$/

str = document.URL

a = regexp.exec(str)

alert(a[0])

Reference: Regular Expressions: Methods - Doc JavaScript [webreference.com]

Some perl one-liners

griflet (guillaume riflet) — Sun, 10 Jun 2007 18:00:56 GMT

Rename htm files to html
In windows:



>dir /B /S | perl -wlne"/([^ ]+)\.htm$/i&&rename$1.'.htm',$1.'.html'"

In linux:



>find | grep htm | perl -wlne'/([^ ]+)\.htm$/i&&rename$1.".htm",$1.".html"'

Check for primality with a regexp

ciconia (Sharon Rosner) — Sun, 18 Mar 2007 14:48:42 GMT

Original perl code here:

http://montreal.pm.org/tech/neil_kandalgaonkar.shtml



class Fixnum

  def prime?

    ('1' * self) !~ /^1?$|^(11+?)\1+$/

  end

end

Create an regexp (Regular expression) from an array of Strings

eddiewould (Eddie) — Tue, 19 Dec 2006 12:36:07 GMT

// description of your code here
Create a DNF regular expression from an array of strings even if they have special characters.



Regexp.new(array.collect{|string| Regexp.escape(string)}.join("|"))

Simple regexp in python working on a string of names and e-mail adresses

kirean73 (Erik Andersson) — Fri, 01 Dec 2006 13:51:35 GMT

Simple regexp in python working on a string of names and e-mail adresses



#!/usr/bin/env python



import re

import sys



mySplit = re.compile (r',', flags=re.MULTILINE)

mailadress = re.compile (r'\<.\D*.\D+@\D+.[.]\D+.\>', flags=re.MULTILINE)



for i in mySplit.split ("Weng Feng , Erik Andersson , Ake Kong goek.se>"):

    k = mailadress.search(i.strip())

    if k:

        print k.group().lstrip("<").rstrip(">")

Split String into roughly equal-sized chunks.

duncanbeevers (Duncan Beevers) — Thu, 21 Sep 2006 00:29:28 GMT

Split a string into an array of roughly equal sized chunks based on a string or regular expression delimiter.
Delimiter is preserved in output.



class String

  def chunk_string(average_segment_size = 40, sclice_on = /\s+/)

    out = []

    slices_estimate = self.size.divmod(average_segment_size)

    slice_count = (slices_estimate[1] > 0 ? slices_estimate[0] + 1 : slices_estimate[0])

    slice_guess = self.size / slice_count

    previous_slice_location = 0

    (1..slice_count - 1).each do

      |i|

      slice_location = self.nearest_split(slice_guess * i, sclice_on)

      out << self.slice(previous_slice_location..slice_location)

      previous_slice_location = slice_location + 1

    end

    out << self.slice(previous_slice_location..self.size)

    out

  end



  def nearest_split(slice_start, slice_on)

    left_scan_location  = (self.slice(0..slice_start).rindex(slice_on)).to_i

    right_scan_location = (self.slice((slice_start+1)..self.size).index(slice_on)).to_i + slice_start

    ((slice_start - left_scan_location) < (right_scan_location - slice_start) ? left_scan_location : right_scan_location)

  end

end

Return the extension from a file name

duncanbeevers (Duncan Beevers) — Thu, 07 Sep 2006 02:06:00 GMT

// Return the extension from a file name



/(.*\.)(.*$)/.match(File.basename(file_name))[2]

Make anchors from urls and email addresses

hjalli (Hjalmar Gislason) — Thu, 01 Sep 2005 02:44:51 GMT

This little PHP function will find urls and email addresses in a block of text and turn them into hyperlinks and mailto: anchors respectively.



function makeLinks($sourceText) {

  $destText = preg_replace( "/([_a-zA-Z0-9-]+)(\.[_a-zA-Z0-9-]+)*@([a-zA-Z0-9-]+)(\.[a-zA-Z0-9-]+)*(\.[a-zA-Z]{2,4})/", '\\0',$sourceText);

  $destText = preg_replace_callback('/\bhttp[^\s]+/',create_function('$matches', 'return "" . preg_replace("#(\.|/)#", "$1", $matches[0]) . "";'),$destText);

  return $destText;

}