Question

Is there a built in way to convert an integer in Ruby into its hexadecimal equivalent?

Something like the opposite of String#to_i:

'0A'.to_i(16) #=>10 

Like perhaps:

'0A'.hex #=>10 

I know how to roll my own, but it’s probably more efficient to use a built in Ruby function.

Answer 1

You can give to_s a base other than 10:

10.to_s(16)  #=> 'a' 

Note that in ruby 2.4 FixNum and BigNum were unified in the Integer class. If you are using an older ruby check the documentation of FixNum#to_s and BigNum#to_s