CODEWITHSUNDEEP
rubyregex
Dave
Dave

Reputation: 19110

How do I match a regex in which the next non-space character is not a "/"?

How do I express in regex the letter "s" whose next non-space character is not a "/"?

I tried this

"str" =~ /s[^[[:space:]]]^\// #=> nil

but it does not even match the simple use case.

Upvotes: 1

Views: 312

Answers (2)

Cary Swoveland
Cary Swoveland

Reputation: 110675

If you merely want to know the number of 's' characters that are not followed by zero or more spaces and then a forward slash (as opposed to their indices in the string), you don't have to use a regular expression.

"sea shells /by the sea s/hore".delete(" ").gsub("s/", "").count("s")
  #=> 3

If you only want to know if there is at least one such 's' you could replace count("s") with include?("s").

I'm not arguing that this is preferable to the use of a regular expression.

Upvotes: 0

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626738

It seems you need to match any s that is not followed with any 0+ whitespace chars and a / after them.

Use

/s(?![[:space:]]*\/)/

See the Rubular demo.

Details

  • s - the letter s
  • (?![[:space:]]*\/) - a negative lookahead that fails the match if, immediately to the right of the current location, there are
    • [[:space:]]* - 0+ whitespaces
    • \/ - a /.

Upvotes: 2

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