Ruby String.index（“ /”）返回-1

Question

I need that the method index return -1 instead of NIL, is there another way? (Ruby programming)

index="asddsa".index("/")
if index==nil
    puts -1
else
    puts index
end

Answer 1

Just do it yourself:

index = "asddsa".index("/") || -1

This works because the expression a = b || c a = b || c assigns b to a if b is not nil / false , and if b is nil / false , it assigns c to a instead. So in this case, when String#index returns nil , it assigns -1 to your index variable (and when it returns a number, it just assigns that to index ).