Today I Learned

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Use A Case Statement As A Cond Statement

Many languages come with a feature that usually takes the name cond statement. It is essentially another way of writing an if-elsif-else statement. The first conditional in the cond statement to evaluate to true will then have its block evaluated.

Ruby doesn’t have a cond statement, but it does have a case statement. By using a case statement with no arguments, we get a cond statement. If we exclude arguments and then put arbitrary conditional statements after the when keywords, we get a construct that acts like a cond statement. Check out the following example:

some_string = "What"

case
when some_string.downcase == some_string
  puts "The string is all lowercase."
when some_string.upcase == some_string
  puts "The string is all uppercase."
else
  puts "The string is mixed case."
end

#=> The string is mixed case.

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