CODEWITHSUNDEEP
ruby
jujajjjj
jujajjjj

Reputation: 55

regex to get all slashes from url

I have the following URL:

localhost:3000/filter/shoes/color/white

I need to replace all slashes to - except the first slash from localhost:3000/.

The final URL must be:

localhost:3000/filter-shoes-color-white

I've tried some regex with ruby but I didn't have any success. Thanks.

Upvotes: 0

Views: 226

Answers (5)

Fravadona
Fravadona

Reputation: 16895

Here is a regexp that match all the / but the first:

\G(?:\A[^\/]*\/)?+[^\/]*\K\/

So you can do:

"localhost:3000/filter/shoes/color/white".gsub(/\G(?:\A[^\/]*\/)?+[^\/]*\K\//,'-')
#=> "localhost:3000/filter-shoes-color-white"

But it won't work if you have a scheme on your URI.

Upvotes: 1

Max
Max

Reputation: 372

And another way of doing it. No regex and "localhost" lookback needed.

[url.split("/").take(2).join("/"),url.split("/").drop(2).join("-")].join("-")

Upvotes: 0

Todd A. Jacobs
Todd A. Jacobs

Reputation: 84343

Using Ruby >= 2.7 with String#partition

Provided you aren't passing in a URI scheme like 'https://' as part of your string, you can do this as a single method chain with String#partition and String#tr. Using Ruby 3.0.2

'localhost:3000/filter-shoes-color-white'.partition(?/).
    map { _1.match?(/^\/$/) ? _1 : _1.tr(?/, ?-) }.join
#=> "localhost:3000/filter-shoes-color-white"

This basically relies on the fact that there are no forward slashes in the first array element returned by #partition, and the second element contains a slash and nothing else. You are then free to use #tr to replace forward slashes with dashes in the final element.

If you have an older Ruby, you'll need a different solution since String#partition wasn't introduced before Ruby 2.6.1. If you don't like using character literals, ternary operators, or numbered block arguments (introduced in Ruby 2.7), then you can refactor the solution to suit your own stylistic tastes.

Upvotes: 0

David Grayson
David Grayson

Reputation: 87386

This is a pretty simple parsing problem, so I question the need for a regular expression. I think the code would probably be easier to understand and maintain if you just iterated through the characters of the string with a loop like this:

def transform(url)
  url = url.dup
  slash_count = 0
  (0...url.size).each do |i|
    if url[i] == '/'
      slash_count += 1
      url[i] = '-' if slash_count >= 2
    end
  end
  url
end

Here is something even simpler using Ruby's String#gsub method:

def transform2(url)
  slash_count = 0
  url.gsub('/') do
    slash_count += 1
    slash_count >= 2 ? '-' : '/'
  end
end

Upvotes: 0

R. Liu
R. Liu

Reputation: 353

TL;DR:

regex is:

\/(?<!localhost:3000\/)

Longer one

A famous old Chinese saying is: Teaching how to fishing is better than giving you the fish.

  1. For regex, you can use online regex site such as regex101.com to test immediately with your regex and test string. link
  2. Found other answers from stackoverflow using other key words to describe your situation: Regex for matching something if it is not preceded by something else
  3. Make you own magic.

Upvotes: 0

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