In my quest to learn the Ruby programming language as a Javascript engineer the unless conditional keyword was a new one for me.

At the end of this post, it is expected that the user should be able to understand the unless conditional Ruby keyword and how it is different from the if keyword

While reading various posts and books about Ruby programming language, you might come across a phrase that says "unless keyword in Ruby is the opposite of the if keyword". Although this statement is helpful, it can also be confusing when you're reading actual code. That said, I came across an illustration that made me understand this concept so much better.

if 2 > 3
   print "this is great" 
else
   print "what is this" 
end

The above is easy to understand, the condition is false, so the program skips the first statement and prints the else statement.

unless 2>3 
print "this is great" 
else 
    print "what is this" 
end

As I mentioned previously, the conditions share similar syntax, but their difference lies in the first condition's evaluation.

in the case of the if conditional, if the first condition is true then the first statement is executed. while the unless conditional only executes the first statement if the condition evaluates to false

using the example above 2 > 3 we know that this condition is false because 2 is less than 3. If this same 2 > 3 condition is in the if block and since it is false, the else statement is executed. The opposite is the case for the unless block where the first statement is always executed as long as the first evaluation is false