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.
5 Answers
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
To summarize:
p 10.to_s(16) #=> "a"
p "%x" % 10 #=> "a"
p "%02X" % 10 #=> "0A"
p sprintf("%02X", 10) #=> "0A"
p "#%02X%02X%02X" % [255, 0, 10] #=> "#FF000A"
Here's another approach:
sprintf("%02x", 10).upcase
see the documentation for sprintf here:
Just in case you have a preference for how negative numbers are formatted:
p "%x" % -1 #=> "..f"
p -1.to_s(16) #=> "-1"
