How to find multiple matches in a string

[Alex DeCaria]

I know how to use regular expressions to find the first match of a
pattern in a string. But, how do I most easily find multiple matches?
For example, if the string is

s = 'abcde_abcde_abcde'

and I want to find the location of ALL the 'b' characters, how do I do
it? If I use

m = s.match(/b/)

then m.offset(0) => [1,2]

but I don't have any information about the second or third occurences of
'b'.

--Alex

 

[Andrea Dallera]

Hei,

s = 'abcde_abcde_abcde'
m = s.scan(/b/)
p m # ['b','b','b']

HTH

 

[Intransition]

I know how to use regular expressions to find the first match of a
pattern in a string. =A0But, how do I most easily find multiple matches?
For example, if the string is

s =3D 'abcde_abcde_abcde'

and I want to find the location of ALL the 'b' characters, how do I do
it?

Try #scan

 

[Robert Klemme]

Hei,

s = 'abcde_abcde_abcde'
m = s.scan(/b/)
p m # ['b','b','b']

Or even

s.scan(/b) {|match| p match}

Kind regards

robert

 

[Alex DeCaria]

Hei,

s = 'abcde_abcde_abcde'
m = s.scan(/b/)
p m # ['b','b','b']

HTH

Thanks Andrea. But is there a way to also find the locations (indexes)
of the 'b' characters?

--Alex

 

[Jesús Gabriel y Galán]

Hei,

=A0 s =3D 'abcde_abcde_abcde'
=A0 m =3D s.scan(/b/)
=A0 p m # ['b','b','b']

HTH

Thanks Andrea. =A0But is there a way to also find the locations (indexes)
of the 'b' characters?

Take a look at this thread, maybe you can get some ideas:

http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/337667

Jesus.

 

[Andrea Dallera]

string = "abcde abcde abcde"
sum = 0
result = []
blocks = string.split(/b/)
blocks.pop
blocks.each do |block|
sum += block.length
result << sum
sum += 1
end
p result # [1,7,13]

Don't tell anyone I've written this crap

--
Andrea Dallera
http://github.com/bolthar/freightrain
http://usingimho.wordpress.com

Hei,

s = 'abcde_abcde_abcde'
m = s.scan(/b/)
p m # ['b','b','b']

HTH

Thanks Andrea. But is there a way to also find the locations (indexes)
of the 'b' characters?

--Alex

 

[Caleb Clausen]

Hei,

s = 'abcde_abcde_abcde'
m = s.scan(/b/)
p m # ['b','b','b']

HTH

Thanks Andrea. But is there a way to also find the locations (indexes)
of the 'b' characters?

I think this works:

s = 'abcde_abcde_abcde'
i=0
while i=s.index('b',i)
do_something_with i
end

 

[Andrea Dallera]

Nope, tried it.

 

[botp]

Nope, tried it.

what do you mean it does not work?

btw, you can also use stringscan. it's fast.

s=3DStringScanner.new "this is a test string"

p s.pos while s.scan_until /s/

4
7
13
16
=3D> nil


pls do not top post.

kind regards -botp

 

[Robert Klemme]

Hei,

s = 'abcde_abcde_abcde'
m = s.scan(/b/)
p m # ['b','b','b']

Thanks Andrea. But is there a way to also find the locations (indexes)
of the 'b' characters?

irb(main):012:0> s="a "*5
=> "a a a a a "
irb(main):013:0> s.scan(/a+/) { p $~, $~.offset(0) }
#<MatchData "a">
[0, 1]
#<MatchData "a">
[2, 3]
#<MatchData "a">
[4, 5]
#<MatchData "a">
[6, 7]
#<MatchData "a">
[8, 9]
=> "a a a a a "
irb(main):014:0>

Kind regards

robert