I just want to assign the value of variable B to variable A only if B is not nil.
And I want to simplify the code as possible.
So I found the one.
A = B if B
But variable name is long such as data[:Symbol1][:Symbol2]... , anyhow same variable name is duplicated.
Can anybody help me with simplifying this code?
You might try the presence method.
Your code would look like
A = B.presence
Example of it in action:
[1] pry(main)> b = nil
=> nil
[2] pry(main)> a = b.presence
=> nil
[3] pry(main)> a
=> nil
[4] pry(main)> b = 'foo'
=> "foo"
[5] pry(main)> a = b.presence
=> "foo"
[6] pry(main)> a
=> "foo"
I'd say you need A = B || A.
The || operator evaluates and returns the first non-false operand. If B is "truthy", it will return B (and assign it to A). If B is false, A will just be assigned itself.