Test if variable matches any of several strings w/o long if-elsif chain, or case-when

by

Perhaps you didn’t know that you can put multiple conditions on a single case:

case mystr
  when "abc", "def", "ghi", "xyz"
    ..
end

But for this specific string-based test, I would use regex:

if mystr =~ /\A(?:abc|def|ghi|xyz)\z/

If you don’t want to construct a regex, and you don’t want a case statement, you can create an array of objects and use Array#include? test to see if the object is in the array:

if [a,b,c,d].include?( o )

or, by monkey-patching Object, you can even turn it around:

class Object
  def in?( *values )
    values.include?( self )
  end
end

if o.in?( a, b, c, d )

More Related Contents:

  1. Very Basic Ruby puts and gets
  2. What’s the difference between equal?, eql?, ===, and ==?
  3. Double vs single quotes
  4. Ruby: String Comparison Issues
  5. Why use symbols as hash keys in Ruby?
  6. What does %w(array) mean?
  7. Ruby function to remove all white spaces?
  8. What’s the difference between a string and a symbol in Ruby?
  9. How to check whether a string contains a substring in Ruby
  10. Why is the shovel operator (
  11. What is the easiest way to remove the first character from a string?
  12. Backslashes in single quoted strings vs. double quoted strings
  13. Ruby 1.9 Array.to_s behaves differently?
  14. Extract a substring from a string in Ruby using a regular expression
  15. obj.nil? vs. obj == nil
  16. Which style of Ruby string quoting do you favour?
  17. Comparing ruby hashes [duplicate]
  18. String interpolation in Ruby doesn’t work?
  19. Measure the distance between two strings with Ruby?
  20. Read binary file as string in Ruby
  21. to_s vs. to_str (and to_i/to_a/to_h vs. to_int/to_ary/to_hash) in Ruby
  22. Why do two strings separated by space concatenate in Ruby?
  23. Convert unicode codepoint to string character in Ruby
  24. Ruby: Merging variables in to a string
  25. Split string by multiple delimiters
  26. What is the use case for Ruby’s %q / %Q quoting methods?
  27. What is the opposite of string.next?
  28. What is the best way to split a string to get all the substrings by Ruby?
  29. Ruby’s File.open and the need for f.close
  30. Using Ruby Symbols

Leave a Comment