Regexp question for doing "and" searches

[Jeff Cohen]

Just can't quite figure this one out.

Given a search phrase like "one two three", I want to search a list of
text strings for onex that contain ALL of those words, but not
necessarily in that order.

The hard part for me is the "not necessarily in that order".

Using '\b(one|two|three)\b' will match if at least one of them occurs in
any order, but I need all of them to match *and* be in any order.

two one three => match
one three => does not match

Any ideas? Is this possible with regular expressions?

Thanks!
Jeff

 

[Andrew Johnson]

Just can't quite figure this one out.

Given a search phrase like "one two three", I want to search a list of
text strings for onex that contain ALL of those words, but not
necessarily in that order.

You can use look-aheads to build a re that looks like:

/^(?=.*\bone\b)(?=.*\btwo\b)(?=.*\bthree\b)/

ensuring a match only if all look-ahead assertions pass.

phrase = "one two three"
re = %r/^#{phrase.split.map{|s|"(?=.*\\b#{s}\\b)"}}/
while DATA.gets
print if ~re
end
__END__
one two three YUP
one three two YUP
zone two three NOPE
three and two and one YUP

regards,
andrew

 

[Joel VanderWerf]

Just can't quite figure this one out.

Given a search phrase like "one two three", I want to search a list of
text strings for onex that contain ALL of those words, but not
necessarily in that order.

The hard part for me is the "not necessarily in that order".

Using '\b(one|two|three)\b' will match if at least one of them occurs in
any order, but I need all of them to match *and* be in any order.

two one three => match
one three => does not match

Seems to work:

s = "foo two bar three zap one"
rx = /^(?=.*one)(?=.*two).*three/m

p (rx =~ s)

s = "one three"
p (rx =~ s)

Works like this too:
rx = /^(?=.*one)(?=.*two)(?=.*three)/m

 

[Jeff Cohen]

You can use look-aheads to build a re that looks like:

/^(?=.*\bone\b)(?=.*\btwo\b)(?=.*\bthree\b)/

ensuring a match only if all look-ahead assertions pass.

Awesome! I'll give it a try.

Thanks a lot.
Jeff

 

[ara.t.howard]

Just can't quite figure this one out.

Given a search phrase like "one two three", I want to search a list of
text strings for onex that contain ALL of those words, but not
necessarily in that order.

The hard part for me is the "not necessarily in that order".

Using '\b(one|two|three)\b' will match if at least one of them occurs in
any order, but I need all of them to match *and* be in any order.

two one three => match
one three => does not match

Any ideas? Is this possible with regular expressions?

Thanks!
Jeff

stupid - but works

harp:~ > cat a.rb
strings = <<-txt
two one three
one three
one foo two bar three
foo two bar one three
two
txt

atoms = '\b(?ne|two|three)\b'
re = %r/(?:#{ atoms }).*(?:#{ atoms }).*(?:#{ atoms })/

require "yaml" and strings.each{|string| y string => (string =~ re ? true : false)}


harp:~ > ruby a.rb
---
" two one three\n": true
---
" one three\n": false
---
" one foo two bar three\n": true
---
" foo two bar one three\n": true
---
" two\n": false

hth.

-a