Raise ArgumentError When Argument is a Hexadecimal Representation - ruby

Question

My script needs to accept only 'plain' integers, and raise an argument error in any other cases (letters, special symbols, floats, multiple arguments). Unfortunately, when the passed arguments is a representation for a hexadecimal like 0b1111 the script interprets it as an integer and accepts it.
Here is my script:
begin
price = Integer ARGV[0]
rescue
raise ArgumentError "the entered value has to be an integer"
end
if ARGV.length > 1
raise ArgumentError, "wrong number of arguments (given #{ARGV.length}, expected 1)"
end
if price < 8
raise ArgumentError, "the entered value has to be at least 8"
end
if price.match?(/[A-Za-z]/)
raise ArgumentError "the entered value has to be an integer"
end
Basically the solution I'm trying is the last block:
if price.match?(/[A-Za-z]/)
raise ArgumentError "the entered value has to be an integer"
end
This gives me an error: undefined method `match?' for 2:Integer (NoMethodError)
If I understand correctly match? only works with strings, but because of the first block the variable price is converted to an integer.
How could I fix my code and would price.match?(/[A-Za-z]/) even solve my problem or do I need a completely different approach?
The desired result:
Input: 0b1111
output: ArgumentError "the entered value has to be an integer

Answer 1

You can use exception: false key for Integer method
Integer(nil, exception: false)
# => nil
Integer("blablabla", exception: false)
# => nil
Integer("9.3", exception: false)
# => nil
Integer("9", exception: false)
# => 9
There is also base (second) arg in this method
Integer("0b1111", exception: false)
# => 15
Integer("0b1111", 10, exception: false)
# => nil
Integer("9.3", 10, exception: false)
# => nil
Integer("9", 10, exception: false)
# => 9
Finally you can use it such way
price = Integer(ARGV[0], 10, exception: false)
raise ArgumentError("the entered value has to be an integer") if price.nil?

Answer 2

After this line
price = Integer(ARGV[0])
the input is already transformed into an integer if a transformation is possible as defined in the example in the documentation of Kernel#Integer.
If you want to ensure only strings that contain pure integer values are transformed then you will need to check the format of the input string first. For example, with a Regexp like this
ARGV[0].match?(/\A\d+\z/)
that returns true when the input only contains digits.
Just replace the first block in your script with
unless ARGV[0].match?(/\A\d+\z/)
raise ArgumentError "the entered value has to be an integer"
end
price = Integer(ARGV[0])
# ...
To simplify testing the preconditions I would change it to
unless ARGV&.size != 1
raise ArgumentError, "wrong number of arguments (given #{ARGV&.size || 0}, expected 1)"
end
unless ARGV[0].match?(/\A\d+\z/)
raise ArgumentError "the entered value has to be an integer with at least 8 digits"
end
price = Integer(ARGV[0])
if price < 8
raise ArgumentError, "the entered value has to be at least 8"
end