Method to groom a string to floating point representation
in [Ruby]
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From: Jean-Julien Fleck on 14 Apr 2010 10:07 Hello Alex, > Yes, there has to be some additional logic to allow a trailing 'e' with > the assumption that the user will next enter a valid character > afterward. That's what makes it a little complicated (and fun) to > figure out. The goal is, as the user is entering data, to not allow > them to enter anything that is obviously not going to work as a floating > point representation. Sure, fun it is :o) But that's exactly the kind of software that could drive me mad (as a user). You assume that your user is making a typo but what if he is not ? What if he truly believe what he is writing is a perfectly correct float ? He will retry again, and again and again untill he decide that the whole software is just a fraud :o) So IMHO, it is more efficient to let your user know what kind of error he is (possibly repetitively) doing and propose an alternative rather than erase what he believe could be right. Cheers, -- JJ Fleck PCSI1 Lycée Kléber
From: Josh Cheek on 14 Apr 2010 10:58 [Note: parts of this message were removed to make it a legal post.] On Wed, Apr 14, 2010 at 8:33 AM, Alex DeCaria <alex.decaria(a)millersville.edu > wrote: > Josh Cheek wrote: > > This is what I have so far, please check and correct any tests that > > should > > be different > > Josh, > > Your code works great! I knew there had to be a more elegant way to do > this rather than my brute force method. > > The only test it didn't seem to work on was eliminating extra + or - > signs, such as '+45-2+8' => '+4528', but now that I see what you are > doing I can probably figure out how to do that. I definitely need to > learn more about regular expressions! > > Thanks for your time and effort. > > --Alex > -- > Posted via http://www.ruby-forum.com/. > > It wasn't done, because I wanted clarification on the tests first. Anyway, this one passes all tests. def clean_string(str) str =~ /\A([-+]?)([eE]?)([^eE.]*\.?)([^eE]*)((?:[eE][+-]?)?)([^Z]*)\Z/ posneg , misplaced_e , before_dec , after_dec , e , exponent = $1 , $2 , $3 , $4 , $5 , $6 posneg + before_dec.gsub(/[^0-9.]/,'') + after_dec.gsub(/[^0-9]/,'') + e + exponent.gsub(/[^0-9]/,'') end require 'test/unit' class TestCleanString < Test::Unit::TestCase def test_delete_chars assert_equal '-24.5e45' , clean_string('-24.5fge4x5') end def test_delete_extra_decimal assert_equal '2.45' , clean_string('2.4.5') assert_equal '2.45' , clean_string('2..45') assert_equal '2.45' , clean_string('2...45') end def test_delete_extra_decimal_in_exponent assert_equal '245e76' , clean_string('245e7.6') end def test_delete_extra_or_misplaced_pos_and_neg_signs assert_equal '+4568e+45' , clean_string('+45-68+e+45-') end def test_delete_extra_or_misplaced_e_or_E assert_equal '4.67e67' , clean_string('4.67e6e-7') assert_equal '+4.67e-7' , clean_string('+e4.67e-7') end end
From: Alex DeCaria on 14 Apr 2010 11:06 Josh Cheek wrote: > On Wed, Apr 14, 2010 at 8:33 AM, Alex DeCaria > <alex.decaria(a)millersville.edu >> wrote: > >> The only test it didn't seem to work on was eliminating extra + or - >> > It wasn't done, because I wanted clarification on the tests first. > > Anyway, this one passes all tests. > Thanks again, Josh! May I use your code in my (non-commercial, educational-use-only) app? --Alex -- Posted via http://www.ruby-forum.com/.
From: Alex DeCaria on 14 Apr 2010 11:09 Jean-Julien Fleck wrote: > > Sure, fun it is :o) > But that's exactly the kind of software that could drive me mad (as a > user). You assume that your user is making a typo but what if he is > not ? What if he truly believe what he is writing is a perfectly > correct float ? He will retry again, and again and again untill he > decide that the whole software is just a fraud :o) So IMHO, it is more > efficient to let your user know what kind of error he is (possibly > repetitively) doing and propose an alternative rather than erase what > he believe could be right. > > Cheers, I can't argue with the point you are making. I will continue to use the automatic string grooming, but will probably include a message to the user letting them know why what they are typing isn't showing up in the textbox. --Alex -- Posted via http://www.ruby-forum.com/.
From: Josh Cheek on 14 Apr 2010 11:19
[Note: parts of this message were removed to make it a legal post.] On Wed, Apr 14, 2010 at 10:06 AM, Alex DeCaria < alex.decaria(a)millersville.edu> wrote: > Josh Cheek wrote: > > On Wed, Apr 14, 2010 at 8:33 AM, Alex DeCaria > > <alex.decaria(a)millersville.edu > >> wrote: > > > >> The only test it didn't seem to work on was eliminating extra + or - > >> > > It wasn't done, because I wanted clarification on the tests first. > > > > Anyway, this one passes all tests. > > > Thanks again, Josh! May I use your code in my (non-commercial, > educational-use-only) app? > > --Alex > -- > Posted via http://www.ruby-forum.com/. > > Sure, go ahead and throw the wtfpl on there, if you feel more comfortable with that. http://sam.zoy.org/wtfpl/ And I guarantee that it does nothing other than pass the set of tests it was posted with, on my machine, with the settings that were used at the time of testing. So no warranty of any kind. Have fun :P |