Check if string matches multiple substrings/regexes

Question

I have an array of paragraphs and an array of keywords. I want to iterate over the paragraphs array and return true for elements that include all of my keywords. The keywords can be in any order, but all of them must be found in the same paragraph in order for it to be true, not just some of them.

Is there a way I can do this using one Regexp.union or one regex, without =~ regex1 && =~ regex2 && =~ regex3 && =~ regex4 etc?

Just words. But I can easily turn it into an array of one-word patterns like `/cromulent/`. — GreenTriangle, Mar 16 '15 at 06:36
This could help: [Regex to match string containing two names in any order](http://stackoverflow.com/q/4389644/477037) — Stefan, Mar 16 '15 at 09:55

score 0 · Answer 1 · answered Mar 16 '15 at 06:37

0

If the pattern array contains only keywords and no patters:

str = "foo went to bar with abc and xyz"

pats = ["abc","xyz","foo","bar"]
pats.all? { |e| str.include?(e) }
# => true

pats = ["abc","xyz","foo","bar", "no"]
pats.all? { |e| str.include?(e) }
# => false

If the pattern array contain patterns:

pats = [/abc/, /xyz$/, /^foo/, /bar/]
pats.all? { |e| str =~ e }
# => true

pats = [/abc/, /xyz$/, /^foo/, /bar/, /no/]
pats.all? { |e| str =~ e }
# => false

answered Mar 16 '15 at 06:37

shivam

16,048
3
56
71

Anchored regexes are unnecessary in the example, I think. No one looks for keywords this way. :) – Sergio Tulentsev Mar 16 '15 at 07:45
@SergioTulentsev that's true. I just wanted to give an example for regex patterns match too. So I lazily used same keywords as patterns :P – shivam Mar 16 '15 at 07:47
I mean, _anchored_ regexes (`/^foo/`) :) – Sergio Tulentsev Mar 16 '15 at 07:53

Cary Swoveland · Answer 2 · 2015-03-16T08:22:27.647

I suggest the following:

str = "I have an array of paragraphs and an array of keywords. I want to iterate over the paragraphs array and return true for elements that include all of my keywords. The keywords can be in any order, but all of them must be found in the same paragraph in order for it to be true, not just some of them."

Edit: I initially misunderstood the question. You can just do the following for each paragraph:

words = %w(have iterate true) 
(words - str.scan(/\w+/)).empty?
  #=> true

words = %w(have iterate cat)
(words - str.scan(/\w+/)).empty?
  #=> false

When I initially read the question I thought the words in the array must appear in each paragraph in the same order. For the record, my solution with that additional requirement follows.

words = %w(have iterate true)   
r = /\b#{words.join('\b.*?\b')}\b/
   #=> /\bhave\b.*?\biterate\b.*?\btrue\b/
str =~ r #=> 2 (a match)

words = %w(true have iterate)
r = /\b#{words.join('\b.*?\b')}\b/
str =~ r #=> nil

words = %w(have iterate true false)   
r = /\b#{words.join('\b.*?\b')}\b/
str =~ r #=> nil

This enforces order of keywords. We don't usually care about the order. — Sergio Tulentsev, Mar 16 '15 at 07:55
@Sergio, ha! I incorrectly interpreted, "...found in the same paragraph in order for it to be true". It's clear from the rest of the question that order is not required. — Cary Swoveland, Mar 16 '15 at 08:00

score -1 · Answer 3 · answered Mar 16 '15 at 07:39

-1

I have never used Ruby but I can give you the logic to use here. Hope it helps

array_words
array_paragraphs
number_words = array_words
count =0

foreach para (array_paragraph)
{
    foreach word (array_word)
    {
        if (para =~ m/word/gi)
        {
            count++
        }
    }
    if (count == number_words)
    {
        print all words present in the paragraph
    }
    count = 0
}

answered Mar 16 '15 at 07:39

Rajinder

41
1
9

1

Ruby can do much much better than _this_. – Sergio Tulentsev Mar 16 '15 at 07:43

Check if string matches multiple substrings/regexes

3 Answers3