Education Ecosystem Blog

 
In programming languages, a “switch statement” is a type of control mechanism used to check if the value of a variable or expression exists and what the program should do from that point. In Ruby, it is implemented using the “case” argument.
 

Case as Switch Statement in Ruby with parameter

The “case” argument always comes with a “when” and “else” associated with it.  It works very similarly to “if-then-else” argument. Bellow, we can see some examples of “case” with a parameter,  and how it behaves according to the type of declaration in each “when” related to it.

case a
When 1
 puts "Single value"
When two, 3
 puts "One of the comma-separated values"
When 4..6
 puts "One of 4, 5, 6"
When 7...9
 puts "One of 7, 8 but not 9"
Else
 puts "Any other thing"
end

 Each “when” declares a situation where the parameter “a” has a possible value that is compared with “a”. These are “cases” which you want to make this assessment. After all the listed cases, it uses the “else” argument to cover all other possibilities.
 

Case as Switch Statement in Ruby without parameter

Case
When b < 3
 puts "Little than 3"
When b == 3
 puts "Equal to 3"
When (1..10) === B
 puts "Something in closed range of [1 ..10]
end

Note that when the parameter is not declared in the “case”, each one of the “when” must have the parameter stated, so that the comparison can be done.

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