Regexp in Ruby

ruby-talk
1

Ruby Regular Expression

1.How to extract the words which are exist with symbols like
punctuation.
For eg:

str='Now, I am Ruby programmer. here, how to list the word which is
exist with symbol like punctuation, comma, or
exclamation.'

that Output may be as:
=>['Now,','programmer.','here,','punctuation,','comma,','exclamation.']

2.from that result, remove the symbol from word and in array. this
result may be as:
=>['Now','programmer','here','punctuation','comma','exclamation']

···

--
Posted via http://www.ruby-forum.com/.

2

From: Selvag Ruby <lists@ruby-forum.com>
To: ruby-talk@ruby-lang.org
Date: 01/27/2014 07:17 AM
Subject: Regexp in Ruby
Sent by: "ruby-talk" <ruby-talk-bounces@ruby-lang.org>

Ruby Regular Expression

1.How to extract the words which are exist with symbols like
punctuation.
For eg:

str='Now, I am Ruby programmer. here, how to list the word which is
exist with symbol like punctuation, comma, or
exclamation.'

that Output may be as:
=>['Now,','programmer.','here,','punctuation,','comma,','exclamation.']

2.from that result, remove the symbol from word and in array. this
result may be as:
=>['Now','programmer','here','punctuation','comma','exclamation']

--
Posted via http://www.ruby-forum.com/\.

This will work. There may be a cleaner way than that match in the collect.
Just change the punctuation list in the scan to match what you need.

arr = str.scan(/\w+[,.!]/)
arr.collect! { |element|
  /\w+/.match(element).to_s
}
p arr

Michael

3

You can avoid the collect by using a match group with scan:

str.scan(/(\w+)[[:punct:]]/).flatten

···

--
Posted via http://www.ruby-forum.com/.

4

Hi,
1. /\w+[^\w\s]/
2. /\w+[\p{P}]/
Try rubular.com for any regex problem

···

On Mon, Jan 27, 2014 at 5:47 PM, Selvag Ruby <lists@ruby-forum.com> wrote:

Ruby Regular Expression

1.How to extract the words which are exist with symbols like
punctuation.
For eg:

str='Now, I am Ruby programmer. here, how to list the word which is
exist with symbol like punctuation, comma, or
exclamation.'

that Output may be as:
=>['Now,','programmer.','here,','punctuation,','comma,','exclamation.']

2.from that result, remove the symbol from word and in array. this
result may be as:
=>['Now','programmer','here','punctuation','comma','exclamation']

--
Posted via http://www.ruby-forum.com/\.

--
--------------------------------
Thanks & Regards
Asif Iquebal Sarkar
Bhubaneswar, Orissa

5

thanks to all replies. your all codes working well. some codes
impressing me to know more of Ruby. Can you explain this code in order
to understand?

···

--
Posted via http://www.ruby-forum.com/.

6

I'll have a go at explaining, although I'm no expert on Regexp.

str.scan(/(\w+)[[:punct:]]/).flatten

"str" - Take the String object

".scan(" - Execute the method "scan" which is available to String.

"/" - Regexp shorthand. A Regular Expression matches a pattern using
special characters.

"(\w+)" - The parentheses indicate a "capture" group. This means that
you can match a specific subsection of the pattern and extract it. The
"\w" means any character in a word, like a letter, number, or
underscore. The "+" means 1 or more.

"[[:punct:]]" - means match punctuation. According to a quick Googling
this is "-[]\;',./!@#%&*()_{}::"?" Because this is outside the capture
group it is excluded.

"/" - Closes the Regexp.

")" - Closes the "scan" argument.

".flatten" - Turns the nested Array returned by using scan with captures
into a simple Array.

···

____________________________
str.scan(/\w+(?=[[:punct:]])/)

The difference with this one is that "(?=" excludes the punctuation from
the output.

According to this:
http://www.tutorialspoint.com/ruby/ruby_regular_expressions.htm

(?= re) Specifies position using a pattern. Doesn't have a range.

--
Posted via http://www.ruby-forum.com/.

7

I understood that words.
but specifically I expected the explanation of [[:punct:]]. In
':punct:',
1. it's closed by double square brackets. why this?
2. there are two colons exists. Is there any reason to?

···

--
Posted via http://www.ruby-forum.com/.

8

Look up "POSIX bracket expressions". I'm not 100% sure, but I think the
reason for the second outer brackets is that something like [:punct:] is
a group, and therefore belongs inside a group, just like like [aeiuo]

···

--
Posted via http://www.ruby-forum.com/.

9

Dear Selvag Ruby,

Growing on the Joel Pearson idea...

str.scan(/(\w+)[[:punct:]]/).flatten

It can be written like ...

str.scan(/\w+(?=[[:punct:]])/)

Abinoam Jr.

···

On Mon, Jan 27, 2014 at 9:48 AM, Joel Pearson <lists@ruby-forum.com> wrote:

You can avoid the collect by using a match group with scan:

str.scan(/(\w+)[[:punct:]]/).flatten

--
Posted via http://www.ruby-forum.com/\.

10

One place to start is Class: Regexp (Ruby 2.1.0)

Hope this helps,

Mike

···

On Jan 28, 2014, at 7:38 AM, Selvag Ruby <lists@ruby-forum.com> wrote:

I understood that words.
but specifically I expected the explanation of [[:punct:]]. In
':punct:',
1. it's closed by double square brackets. why this?
2. there are two colons exists. Is there any reason to?

--
Posted via http://www.ruby-forum.com/\.

--

Mike Stok <mike@stok.ca>
http://www.stok.ca/~mike/

The "`Stok' disclaimers" apply.