Get Number of regex matches

ruby-talk
1

Hi,

how can I get the NUMBER of matches for a regular expression in a given
string?

For example: for string 'Banana' and regex /a/ I should get '3'
(matches)

Thanks!
Ingo

···

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

2

Here's one way (but there are probably better ones):

"Banana".scan(/a/).size
=> 3

max

···

On 12/7/06, Ingo Weiss <ingoweiss@gmail.com> wrote:

Hi,

how can I get the NUMBER of matches for a regular expression in a given
string?

For example: for string 'Banana' and regex /a/ I should get '3'
(matches)

3

One way is:
'Banana'.scan(/a/).size

I'm not sure how to get it out of the MatchData returned by 'match' or
=~, unfortunately.

···

On 12/6/06, Ingo Weiss <ingoweiss@gmail.com> wrote:

Hi,

how can I get the NUMBER of matches for a regular expression in a given
string?

For example: for string 'Banana' and regex /a/ I should get '3'
(matches)

4

This one skips the intermediate array construction in return for some
clunkiness:

i = 0
banana.scan(/a/) { i += 1}
i

martin

···

On 12/7/06, Max Muermann <ruby@muermann.org> wrote:

On 12/7/06, Ingo Weiss <ingoweiss@gmail.com> wrote:
> Hi,
>
> how can I get the NUMBER of matches for a regular expression in a given
> string?
>
> For example: for string 'Banana' and regex /a/ I should get '3'
> (matches)
>

Here's one way (but there are probably better ones):

"Banana".scan(/a/).size
=> 3

5

> Hi,
>
> how can I get the NUMBER of matches for a regular expression in a given
> string?
>
> For example: for string 'Banana' and regex /a/ I should get '3'
> (matches)
>

Here's one way (but there are probably better ones):

"Banana".scan(/a/).size
=> 3

This one skips the intermediate array construction in return for some
clunkiness:

i = 0
banana.scan(/a/) { i += 1}
i

>> require 'enumerator'
=> true
>> "banana".to_enum(:scan, /a/).inject(0) {|s,| s+1}
=> 3

:slight_smile:

  robert

···

On 06.12.2006 22:44, Martin DeMello wrote:

On 12/7/06, Max Muermann <ruby@muermann.org> wrote:

On 12/7/06, Ingo Weiss <ingoweiss@gmail.com> wrote:

6

Thank you very much for all your great suggestions!

Ingo

···

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

7

banana.split('').reject { |i| i if i != 'a' }.length

I want extra points for using "banana.split".

Best,
James

···

On 2006-12-07 04:02:55 -0500, Robert Klemme <shortcutter@googlemail.com> said:

On 06.12.2006 22:44, Martin DeMello wrote:

On 12/7/06, Max Muermann <ruby@muermann.org> wrote:

On 12/7/06, Ingo Weiss <ingoweiss@gmail.com> wrote:
> Hi,
>
> how can I get the NUMBER of matches for a regular expression in a given
> string?
>
> For example: for string 'Banana' and regex /a/ I should get '3'
> (matches)
>

Here's one way (but there are probably better ones):

"Banana".scan(/a/).size
=> 3

This one skips the intermediate array construction in return for some
clunkiness:

i = 0
banana.scan(/a/) { i += 1}
i

>> require 'enumerator'
=> true
>> "banana".to_enum(:scan, /a/).inject(0) {|s,| s+1}
=> 3

:slight_smile:

  robert