# Hel;p with Tip Calculator **URL:** \ **Category:** Ruby\ **Created:** [August 8, 2010, 5:46pm UTC](https://www.ruby-forum.com/t/hel-p-with-tip-calculator/192929 "2010-08-08T17:46:26Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![humandictionary](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/65b543/32.png) [@humandictionary](https://www.ruby-forum.com/u/humandictionary)\ **Post date:** [August 8, 2010, 5:46pm UTC](https://www.ruby-forum.com/t/hel-p-with-tip-calculator/192929/1 "2010-08-08T17:46:26Z")
puts “What is the total?” input = gets.chomp.to\_i puts “What percent do you want to tip?” input2 = gets.chomp.to\_i percent = 100 tip = input2 \* input \* 0.01 puts “You should tip $#{tip}” This is a tip calculator. I want it to work if the person enters $45 or 15%. Right now, it would only return 0 because they are invalid numbers. It would only work with an input of 15 or 45. I have really no clue how to do that. ---
**Author:** ![humandictionary](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/65b543/32.png) [@humandictionary](https://www.ruby-forum.com/u/humandictionary)\ **Post date:** [August 8, 2010, 6:00pm UTC](https://www.ruby-forum.com/t/hel-p-with-tip-calculator/192929/2 "2010-08-08T18:00:07Z")
On Mon, 9 Aug 2010 00:46:29 +0900 Hd Pwnz0r [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Right now, it would only return 0 because they are invalid numbers. It > would only work with an input of 15 or 45. I have really no clue how > to do that. Use ‘45 %’.sub(/%/, ‘’).strip ‘14 $’.sub(/[$]/, ‘’).strip for that. “strip” can remove unwanted trailing and leading blanks. “sub” substitutes the charachters in the RE with an empty string removing them. Regards, Andrei ---
**Author:** ![humandictionary](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/65b543/32.png) [@humandictionary](https://www.ruby-forum.com/u/humandictionary)\ **Post date:** [August 8, 2010, 6:20pm UTC](https://www.ruby-forum.com/t/hel-p-with-tip-calculator/192929/3 "2010-08-08T18:20:36Z")
On Sun, Aug 8, 2010 at 8:59 AM, Andrei B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Use > > ‘45 %’.sub(/%/, ‘’).strip > ‘14 $’.sub(/[$]/, ‘’).strip More universally input\_string.gsub(/\D/, ‘’) removes any non-[0-9] characters, including white space. ---
**Author:** ![humandictionary](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/65b543/32.png) [@humandictionary](https://www.ruby-forum.com/u/humandictionary)\ **Post date:** [August 10, 2010, 3:51pm UTC](https://www.ruby-forum.com/t/hel-p-with-tip-calculator/192929/4 "2010-08-10T15:51:44Z")
Hassan S. wrote: > On Sun, Aug 8, 2010 at 8:59 AM, Andrei B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > wrote: > > > Use > > > > ‘45 %’.sub(/%/, ‘’).strip > > ‘14 $’.sub(/[$]/, ‘’).strip > > More universally > > input\_string.gsub(/\D/, ‘’) > > removes any non-[0-9] characters, including white space. I get: tax.rb:6:in `
': undefined method `gsub’ for 0:Fixnum (NoMethodError) When using that code. As for Andrei, thanks, that’s a good quick fix. ---
**Author:** ![humandictionary](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/65b543/32.png) [@humandictionary](https://www.ruby-forum.com/u/humandictionary)\ **Post date:** [August 10, 2010, 3:58pm UTC](https://www.ruby-forum.com/t/hel-p-with-tip-calculator/192929/5 "2010-08-10T15:58:31Z")
On Tue, Aug 10, 2010 at 6:51 AM, Hd Pwnz0r [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > input\_string.gsub(/\D/, ‘’) > tax.rb:6:in `
': undefined method `gsub’ for 0:Fixnum > (NoMethodError) > > When using that code. Yes, it works on _strings_ – that was the problem you posed. If you already have a _number_, it’s not going to include any symbols like “$” or “%” in the first place. ---
**Author:** ![humandictionary](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/65b543/32.png) [@humandictionary](https://www.ruby-forum.com/u/humandictionary)\ **Post date:** [August 11, 2010, 3:38am UTC](https://www.ruby-forum.com/t/hel-p-with-tip-calculator/192929/6 "2010-08-11T03:38:46Z")
or just > > input\_string.to\_s.gsub(/\D/,‘’) > > for number format permitted 2010/8/10 Hassan S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![humandictionary](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/65b543/32.png) [@humandictionary](https://www.ruby-forum.com/u/humandictionary)\ **Post date:** [August 11, 2010, 6:19am UTC](https://www.ruby-forum.com/t/hel-p-with-tip-calculator/192929/7 "2010-08-11T06:19:08Z")
On Tue, Aug 10, 2010 at 6:38 PM, jason joo [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > or just > > > > input\_string.to\_s.gsub(/\D/,‘’) > > > for number format permitted Depending on what your actual numeric use case is 🙂 $ irb > > input = 9 > > =\> 9 > > input.to\_s.gsub(/\D/,‘’) > > =\> “9” > > input = 9.095 > > =\> 9.095 > > input.to\_s.gsub(/\D/,‘’) > > =\> “9095” ---
**Author:** ![humandictionary](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/65b543/32.png) [@humandictionary](https://www.ruby-forum.com/u/humandictionary)\ **Post date:** [August 11, 2010, 7:05am UTC](https://www.ruby-forum.com/t/hel-p-with-tip-calculator/192929/8 "2010-08-11T07:05:22Z")
aha, i forgot positive number and dot. then the regular expression should be /([-+]?\d\*[.]?\d\*)/ eg if input\_string =~ /([-+]?\d\*[.]?\d\*)/ input\_string = $1 else #have no number part input\_string = 0 end 9 =\> “9” -9 =\> “-9” -9.098 =\> “-9.098” 2010/8/11 Hassan S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![humandictionary](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/65b543/32.png) [@humandictionary](https://www.ruby-forum.com/u/humandictionary)\ **Post date:** [August 11, 2010, 8:15pm UTC](https://www.ruby-forum.com/t/hel-p-with-tip-calculator/192929/9 "2010-08-11T20:15:42Z")
At 2010-08-11 01:03AM, “jason joo” wrote: > [Note: parts of this message were removed to make it a legal post.] > > aha, i forgot positive number and dot. then the regular expression should > be /([-+]?\d\*[.]?\d\*)/ The empty string matches that pattern (all your quantifiers allow zero of the previous item). You want: ``` /[-+]?(?:\d+(\.\d*)?)|(?:\d*\.\d+)/ ``` where there must be at least one digit.