# False positives in editing data **URL:** \ **Category:** ruby-talk\ **Created:** [19 November 2007 05:39 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312 "2007-11-19T05:39:59Z")\ **Posts on this page:** 19\ **Page:** 2
**Author:** ![Alex\_Young](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@Alex\_Young](https://rubytalk.org/u/Alex_Young)\ **Post date:** [21 November 2007 18:37 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/21 "2007-11-21T18:37:02Z")
Clifford Heath wrote: > RichardOnRails wrote: > > > > > >        sName =~ /^([\d]+)?\.?([\d]+)?\.?([\d]+)?\.?/ > > > > > > sName > > > > Did you draw attention to this because of the Hungarian notation? If > > so, do you think I'm unwise to adopt the style once advocated by > > Charles Simoni, super-programmer and co-founder of a giant software > > company? > > Yes. Adamantly, and definitely yes. Interesting article on why (and where it comes from, and why it might not have been such a bad idea) here:    [Making Wrong Code Look Wrong – Joel on Software](http://www.joelonsoftware.com/articles/Wrong.html) > **···** > > -- > Alex ---
**Author:** ![Richard3](https://avatars.discourse-cdn.com/v4/letter/r/b5a626/32.png) [@Richard3](https://rubytalk.org/u/Richard3)\ **Post date:** [22 November 2007 01:10 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/22 "2007-11-22T01:10:07Z")
> RichardOnRails wrote: > \ > \>\> Those evals are TERRIFYING. Don't use them. > > \> How else can you loop through $1, $2 ... without repetitive code? > > I don't think anyone has replied to this, so... > > This is what you've got: > > \> sName =~ /^([\d]+)?\.?([\d]+)?\.?([\d]+)?\.?/ > > \> # Save match variables in n[1] ... n[MLN+1] > \> n = Array.new > \> (1..MLN+1).each { |i| eval %{n[i] = $#{i}} } > > You can get an equivalent for n with the String#match method: > > irb(main):001:0\> name = "2.2.02Topic 2.2.2" > =\> "2.2.02Topic 2.2.2" > irb(main):002:0\> m = name.match( /^([\d]+)?\.?([\d]+)?\.?([\d]+)?\.?/ ) > =\> #\ > irb(main):003:0\> m[1] > =\> "2" > irb(main):004:0\> m[2] > =\> "2" > irb(main):005:0\> m[3] > =\> "02" > > You should be able to use that to get around your second eval, too. > > -- > Alex Hi Alex, > m = name.match( /^([\d]+)?\.?([\d]+)?\.?([\d]+)?\.?/ ) Thanks. Best wishes, Richard > **···** > > On Nov 21, 1:53 pm, Alex Young \ wrote: > > > \> On Nov 19, 2:23 am, Ryan Davis \ wrote: ---
**Author:** ![Richard3](https://avatars.discourse-cdn.com/v4/letter/r/b5a626/32.png) [@Richard3](https://rubytalk.org/u/Richard3)\ **Post date:** [22 November 2007 01:30 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/23 "2007-11-22T01:30:04Z")
> RichardOnRails wrote: > \>\>\>\> sName =~ /^([\d]+)?\.?([\d]+)?\.?([\d]+)?\.?/ > \>\> sName > > \> Did you draw attention to this because of the Hungarian notation? If > \> so, do you think I'm unwise to adopt the style once advocated by > \> Charles Simoni, super-programmer and co-founder of a giant software > \> company? > > Yes. Adamantly, and definitely yes. > > I might have been a bad idea when he had it, even though to his > credit he was trying to make the best of a bad situation, where > MS had bought the worst C compiler on the planet because the good > ones weren't for sale - they could make more money \*not\* selling > to MS. Because of a spate of bugs and bad code churned out by the > MS software factory, many caused by type mismatches on function > parameters that weren't detected either at compile time or at > runtime, Hungarian notation \*might\* have been a good idea once. > > It's definitely \*not\* a good idea with modern C, and even less of > a good idea with Ruby. > > Clifford Heath. Hi Clifford, > It's definitely \*not\* a good idea with modern C, and even less of > a good idea with Ruby. I don't know anything about Microsoft's choice of compilers. But I used several C compilers in the '80s, and all cases found Hungarian notation helpful. I don't think Microsoft's initial choice of compilers is relevant to my and other's successful employment of that convention. Why would it be a bad idea with modern C compilers or with Ruby? You offer no reason. All it does is add one or two letters before names! That doesn't bother any human or compiler or interpreter. To my ears, it sounds like you're telling me you like chocolate after learning that I like vanilla. I'm reminded of George Wallace's assessment of the difference between Democrats vs. Republicans: "There's not a dime's worth of difference. Best wishes, Richard > **···** > > On Nov 21, 12:39 pm, Clifford Heath \ wrote: ---
**Author:** ![Richard3](https://avatars.discourse-cdn.com/v4/letter/r/b5a626/32.png) [@Richard3](https://rubytalk.org/u/Richard3)\ **Post date:** [26 November 2007 20:25 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/24 "2007-11-26T20:25:01Z")
Hi Rick, I loved your blog. Thanks for posting it and informing me about it. I think my usage of "Hungarian" consistent with Simonyi's intent, at least how I understand it. In any case, I find my uasage helpful, as I mentioned to Alex Young on this thread, though I may have to sanitize future posts to avoid people who don't respond to what I mean but instead waste time on how I express my question. Best wishes, Richard > **···** > > On Nov 21, 8:44 pm, Rick DeNatale \ wrote: > > > On Nov 20, 2007 9:35 PM, RichardOnRails \> \> \ wrote: > > > > \> On Nov 19, 2:23 am, Ryan Davis \ wrote: > > > > \> \> \>\> sName =~ /^([\d]+)?\.?([\d]+)?\.?([\d]+)?\.?/ > > > > \> \> sName > > > > \> Did you draw attention to this because of the Hungarian notation? If > > \> so, do you think I'm unwise to adopt the style once advocated by > > \> Charles Simoni, super-programmer and co-founder of a giant software > > \> company? > > > > Actually this form of Hungarian notation, which was called System > > Hungarian in Microsoft, is NOT what Simonyi originally sugested (and > > what was used in the Application Division). > > > > [http://talklikeaduck.denhaven2.com/articles/2007/04/09/hungarian-ducks](http://talklikeaduck.denhaven2.com/articles/2007/04/09/hungarian-ducks) > > > > -- > > Rick DeNatale > > > > My blog on Rubyhttp://talklikeaduck.denhaven2.com/ ---
**Author:** ![Raul\_Parolari](https://avatars.discourse-cdn.com/v4/letter/r/49beb7/32.png) [@Raul\_Parolari](https://rubytalk.org/u/Raul_Parolari)\ **Post date:** [27 November 2007 01:36 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/25 "2007-11-27T01:36:20Z")
RichardOnRails wrote: > I forgot to tell you that I finally understand your second example. > > > md = s.match( /^ (.\*) [a-zA-Z] /x ) > > md[1] # =\> "2.1Topi" > > Without the question mark, in principal, the ".\* initially consumes > all the characters, but then it sees the match fails, because there's > no match for the "[a-zA-Z]". So the ".\*" sort of "backs off" and > satisfies it self with "2.1Topi", leaving the "c" to satisfy "[a-zA- > Z]". Very good, Richard! It is a question on when one is 'content'; if you need a metaphor to remember it, think of a WallStreet banker (.\*, .+) vs a Franciscan monk (.\*?, .+?) 🙂 > The one I like settled on is: > > s="2.1Topic 2.1" > md = s.match( /^ ([\.\d]\*) [^\.\d] /x ) >   #md[0]=2.1T >   #md[1]=2.1 I see that you have solved the problem in your previous post (that I could not reply to), when you wrote (removing all other code): s = "2.002.1Topic 2.2.1" s =~ /^ (\d+[.]?)+ [^\.\d] /x I must confess: I was stunned myself that it did not work; foolish of us, in fact it was working, but you failed to collect the bounty! you needed parenthesis to include the '+'! s =~ /^ ((\d+[.]?)+) [^\.\d] /x p $1, 2 # =\> "2.002.1", "1" However it is better to avoid collecting also the inner results as they overwrite each other in $2 and then confuse us (that's the reason that you saw the last digit captured above..); so let's use the '?:' trick, to avoid writing in $2, where instead we will capture the 'non digits/dots' that come after: s =~ /^ ((?:\d+[.]?)\*) ([^\.\d]+) /x p $1, $2 # =\> "2.002.1", "Topic " Do you see it? I think you do. Now, to finish, let's examine how you solved the problem in this post: > s="2.1Topic 2.1" > md = s.match( /^ ([.\d]\*) [^\.\d] /x ) Ah, you resorted to 'pragmatism'.. you said: "the bloody '\d+[.]?)+' does not work, so I will change it". This was ok, but do you see the difference between:    ((?:\d+[.]?)\*) # I changed + -\> \* to compare    ([\d[.]]\*) aside that the second one is easier to read? (you may want to stop reading and think about this as this is your test to graduate from "intermediate level regexp" 🙂 Ok: if they could speak, they would say respectively: 1) I want 0 or more sequences of (digits followed optionally by a dot) 2) I want 0 or more combinations of digits and dots as they come Do you see? both would match: "2.002.1" but the 2nd would also match "...1..37"! The last question you had was: how do I pick up the digits once I collected the "2.002.1"? Study scan in Pickaxe and then do: str = "2.002.1" str.scan(/ (\d+) /x) # =\> [["2"], ["002"], ["1"]] All right, let's call it a Regexp day, Raul > **···** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Jordan\_Callicoat](https://avatars.discourse-cdn.com/v4/letter/j/9de053/32.png) [@Jordan\_Callicoat](https://rubytalk.org/u/Jordan_Callicoat)\ **Post date:** [27 November 2007 02:15 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/26 "2007-11-27T02:15:03Z")
Hi Richard, Here's a cheat-sheet for ruby regular expression syntax: [http://www.geocities.jp/kosako3/oniguruma/doc/RE.txt](http://www.geocities.jp/kosako3/oniguruma/doc/RE.txt) Regards, Jordan ---
**Author:** ![Alex\_Young](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@Alex\_Young](https://rubytalk.org/u/Alex_Young)\ **Post date:** [22 November 2007 01:42 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/27 "2007-11-22T01:42:05Z")
RichardOnRails wrote: > > RichardOnRails wrote: > > > > > > > >        sName =~ /^([\d]+)?\.?([\d]+)?\.?([\d]+)?\.?/ > > > > > > > > sName > > > > > > Did you draw attention to this because of the Hungarian notation? If > > > so, do you think I'm unwise to adopt the style once advocated by > > > Charles Simoni, super-programmer and co-founder of a giant software > > > company? > > > > Yes. Adamantly, and definitely yes. > > > > I might have been a bad idea when he had it, even though to his > > credit he was trying to make the best of a bad situation, where > > MS had bought the worst C compiler on the planet because the good > > ones weren't for sale - they could make more money \*not\* selling > > to MS. Because of a spate of bugs and bad code churned out by the > > MS software factory, many caused by type mismatches on function > > parameters that weren't detected either at compile time or at > > runtime, Hungarian notation \*might\* have been a good idea once. > > > > It's definitely \*not\* a good idea with modern C, and even less of > > a good idea with Ruby. > > > > Clifford Heath. > > Hi Clifford, > > > It's definitely \*not\* a good idea with modern C, and even less of > > a good idea with Ruby. > > I don't know anything about Microsoft's choice of compilers. But I > used several C compilers in the '80s, and all cases found Hungarian > notation helpful. I don't think Microsoft's initial choice of > compilers is relevant to my and other's successful employment of that > convention. > > Why would it be a bad idea with modern C compilers or with Ruby? You > offer no reason. All it does is add one or two letters before names! > That doesn't bother any human or compiler or interpreter. It depends on the type of Hungarian that you're using, and it's not clear from your code sample which it is. If you're using an abbreviation prefix to denote a semantic difference within a type, then that's (potentially) useful, in both Ruby and C:    us\_username = read\_unsafe\_input()    s\_username = sanitise(us\_username) with us\_ meaning unsafe and s\_ meaning safe, for example. Not something I'd use myself, but I can see the utility. If it's denoting a class, then it's not something I can see as useful, in either C or Ruby. In C, you're duplicating the compiler's type-checking, and in Ruby, duck-typing means that you shouldn't need to care; it becomes readability-damaging line noise. > **···** > > > On Nov 21, 12:39 pm, Clifford Heath \ wrote: > > -- > Alex ---
**Author:** ![Todd\_Benson](https://avatars.discourse-cdn.com/v4/letter/t/34f0e0/32.png) [@Todd\_Benson](https://rubytalk.org/u/Todd_Benson)\ **Post date:** [22 November 2007 02:44 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/28 "2007-11-22T02:44:44Z")
Harry is quoting from the movie Airplane (1980) 🙂 Todd > **···** > > On Nov 20, 2007 7:24 PM, RichardOnRails \ wrote: > > > On Nov 20, 10:22 am, Harry Kakueki \ wrote: > > \> By the way, stop calling me Shirley. 🙂 > > \> And stop calling me Ryan. 🙂 > > \> > > \> Good luck, > > \> > > \> Harry > > Hi Harry, > > > > I apologize for the "Ryan" thing. Ryan was the first response on this > > thread and got mixed up. I don't know about the "Shirley" thing. ---
**Author:** ![Richard3](https://avatars.discourse-cdn.com/v4/letter/r/b5a626/32.png) [@Richard3](https://rubytalk.org/u/Richard3)\ **Post date:** [27 November 2007 03:15 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/29 "2007-11-27T03:15:00Z")
> Hi Richard, > > Here's a cheat-sheet for ruby regular expression syntax: > > [サービス終了のお知らせ](http://www.geocities.jp/kosako3/oniguruma/doc/RE.txt) > > Regards, > Jordan Hi Jordan, > [サービス終了のお知らせ](http://www.geocities.jp/kosako3/oniguruma/doc/RE.txt) Thanks. I'm running ruby 1.8.2 (2004-12-25) [i386-mswin32]. How can I tell if it uses Oniguruma RE ver.5.6.0? "gem list oniguruma -b" gave me: \*\*\* LOCAL GEMS \*\*\* [nothing] \*\*\* REMOTE GEMS \*\*\* oniguruma (1.1.0, 1.0.1, 1.0.0, 0.9.1, 0.9.0) Judging by this result, I'd say the "5.6.0" is the version of the Cheat Sheet itself; and that I don't have Oniguruma installed. I've got The Ruby Way, ver. 2, that covers Oniguruma. But I'm fairly new to Ruby, so I wonder whether stepping up to Oniguruma is prudent. Any ideas? Regards, Richard Regards, Richard > **···** > > On Nov 26, 9:14 pm, MonkeeSage \ wrote: ---
**Author:** ![Richard3](https://avatars.discourse-cdn.com/v4/letter/r/b5a626/32.png) [@Richard3](https://rubytalk.org/u/Richard3)\ **Post date:** [28 November 2007 01:30 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/30 "2007-11-28T01:30:00Z")
> RichardOnRails wrote: > > \> I forgot to tell you that I finally understand your second example. > > \>\> md = s.match( /^ (.\*) [a-zA-Z] /x ) > \>\> md[1] # =\> "2.1Topi" > > \> Without the question mark, in principal, the ".\* initially consumes > \> all the characters, but then it sees the match fails, because there's > \> no match for the "[a-zA-Z]". So the ".\*" sort of "backs off" and > \> satisfies it self with "2.1Topi", leaving the "c" to satisfy "[a-zA- > \> Z]". > > Very good, Richard! > It is a question on when one is 'content'; if you need a metaphor to > remember it, think of a WallStreet banker (.\*, .+) vs a Franciscan monk > (.\*?, .+?) > 🙂 > > \> The one I like settled on is: > > \> s="2.1Topic 2.1" > \> md = s.match( /^ ([\.\d]\*) [^\.\d] /x ) > \> #md[0]=2.1T > \> #md[1]=2.1 > > I see that you have solved the problem in your previous post (that I > could not reply to), when you wrote (removing all other code): > > s = "2.002.1Topic 2.2.1" > > s =~ /^ (\d+[.]?)+ [^\.\d] /x > > I must confess: I was stunned myself that it did not work; foolish of > us, in fact it was working, but you failed to collect the bounty! you > needed parenthesis to include the '+'! > > s =~ /^ ((\d+[.]?)+) [^\.\d] /x > > p $1, 2 # =\> "2.002.1", "1" > > However it is better to avoid collecting also the inner results as they > overwrite each other in $2 and then confuse us (that's the reason that > you saw the last digit captured above..); so let's use the '?:' trick, > to avoid writing in $2, where instead we will capture the 'non > digits/dots' that come after: > > s =~ /^ ((?:\d+[.]?)\*) ([^\.\d]+) /x > > p $1, $2 # =\> "2.002.1", "Topic " > > Do you see it? I think you do. Now, to finish, let's examine how you > solved the problem in this post: > > \> s="2.1Topic 2.1" > \> md = s.match( /^ ([.\d]\*) [^\.\d] /x ) > > Ah, you resorted to 'pragmatism'.. you said: "the bloody '\d+[.]?)+' > does not work, so I will change it". This was ok, but do you see the > difference between: > >    ((?:\d+[.]?)\*) # I changed + -\> \* to compare > >    ([\d[.]]\*) > > aside that the second one is easier to read? (you may want to stop > reading and think about this as this is your test to graduate from > "intermediate level regexp" 🙂 > > Ok: if they could speak, they would say respectively: > 1) I want 0 or more sequences of (digits followed optionally by a dot) > 2) I want 0 or more combinations of digits and dots as they come > > Do you see? > both would match: "2.002.1" but the 2nd would also match "...1..37"! > > The last question you had was: how do I pick up the digits once I > collected the "2.002.1"? Study scan in Pickaxe and then do: > > str = "2.002.1" > > str.scan(/ (\d+) /x) # =\> [["2"], ["002"], ["1"]] > > All right, let's call it a Regexp day, > > Raul > > -- > Posted viahttp://www.ruby-forum.com/. Hi Raul, Thank you for your further support of my obstinacy ƒº Your help has guided me to the solution I wanted. Your original one is succinct, perhaps even elegant in that it decomposes the problem into two sub- problems which admit of essentially one-line solutions. While I truly appreciate that approach, I wanted to find a "natural" solution, which is the one included below. It has one caveat: it's aimed at processing files of only a few megabytes. That said, I'd be pleased to hear of any downsides you may foresee. > \> I forgot to tell you that I finally understand your second example. > [snip] > Very good, Richard! > It is a question on when one is 'content'; if you need a metaphor ... Thanks. I've got that stuff wired into brain now. > I must confess: I was stunned myself that it did not work; foolish of > us, in fact it was working, but you failed to collect the bounty! you > needed parenthesis to include the '+'! That approach is old news, now that I've conceived of my "natural" approach > However it is better to avoid collecting also the inner results as they > overwrite each other in $2 and then confuse us Understood! As you'll see, I avoided that pitfall below. [snip] > Do you see it? I think you do. Quit so. [snip] This was ok, but do you see the > difference between: > >    ((?:\d+[.]?)\*) # I changed + -\> \* to compare > >    ([\d[.]]\*) [snip] > Do you see? For sure! > All right, let's call it a Regexp day, I'll drink to that! With Thanks and Best Wishes, I remain Yours truly, Richard # "Natural" Solution input = \<\ **Author:** ![Richard3](https://avatars.discourse-cdn.com/v4/letter/r/b5a626/32.png) [@Richard3](https://rubytalk.org/u/Richard3)\ **Post date:** [26 November 2007 19:55 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/31 "2007-11-26T19:55:06Z") > RichardOnRails wrote: > \>\> RichardOnRails wrote: > \>\>\>\>\>\> sName =~ /^([\d]+)?\.?([\d]+)?\.?([\d]+)?\.?/ > \>\>\>\> sName > \>\>\> Did you draw attention to this because of the Hungarian notation? If > \>\>\> so, do you think I'm unwise to adopt the style once advocated by > \>\>\> Charles Simoni, super-programmer and co-founder of a giant software > \>\>\> company? > \>\> Yes. Adamantly, and definitely yes. > > \>\> I might have been a bad idea when he had it, even though to his > \>\> credit he was trying to make the best of a bad situation, where > \>\> MS had bought the worst C compiler on the planet because the good > \>\> ones weren't for sale - they could make more money \*not\* selling > \>\> to MS. Because of a spate of bugs and bad code churned out by the > \>\> MS software factory, many caused by type mismatches on function > \>\> parameters that weren't detected either at compile time or at > \>\> runtime, Hungarian notation \*might\* have been a good idea once. > > \>\> It's definitely \*not\* a good idea with modern C, and even less of > \>\> a good idea with Ruby. > > \>\> Clifford Heath. > > \> Hi Clifford, > > \>\> It's definitely \*not\* a good idea with modern C, and even less of > \>\> a good idea with Ruby. > > \> I don't know anything about Microsoft's choice of compilers. But I > \> used several C compilers in the '80s, and all cases found Hungarian > \> notation helpful. I don't think Microsoft's initial choice of > \> compilers is relevant to my and other's successful employment of that > \> convention. > > \> Why would it be a bad idea with modern C compilers or with Ruby? You > \> offer no reason. All it does is add one or two letters before names! > \> That doesn't bother any human or compiler or interpreter. > > It depends on the type of Hungarian that you're using, and it's not > clear from your code sample which it is. If you're using an > abbreviation prefix to denote a semantic difference within a type, then > that's (potentially) useful, in both Ruby and C: > >    us\_username = read\_unsafe\_input() >    s\_username = sanitise(us\_username) > > with us\_ meaning unsafe and s\_ meaning safe, for example. Not something > I'd use myself, but I can see the utility. If it's denoting a class, > then it's not something I can see as useful, in either C or Ruby. In C, > you're duplicating the compiler's type-checking, and in Ruby, > duck-typing means that you shouldn't need to care; it becomes > readability-damaging line noise. > > -- > Alex Hi Alex, > abbreviation prefix to denote a semantic difference within a > type, then that's (potentially) useful, in both Ruby and C: >    us\_username = read\_unsafe\_input() >    s\_username = sanitise(us\_username) I like that. > If it's denoting a class, > then it's not something I can see as useful I like to know merely by inspection whether a referent denotes an integer, a string, a hash or an array of such things. I'd like to avoid "Syntax error" simply because I failed to include a to\_s, to\_i, or whatever. I really can't see why a prefixed lower-case letter or two before a camel-case object name can create so much discussion irrelevant to the question at hand. Maybe I'll have so "sanitize" all the code I post to exemplify a coding issue. Thank you for your response, notwithstanding my lack of total agreement. Best wishes, Richard > **···** > > On Nov 21, 8:42 pm, Alex Young \ wrote: > > > \> On Nov 21, 12:39 pm, Clifford Heath \ wrote: ---
**Author:** ![Richard3](https://avatars.discourse-cdn.com/v4/letter/r/b5a626/32.png) [@Richard3](https://rubytalk.org/u/Richard3)\ **Post date:** [26 November 2007 20:35 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/32 "2007-11-26T20:35:34Z")
Thanks, Todd. That was over my head. "Airplane" was not a movie I'd run to see 🙂 Regards, Richard > **···** > > On Nov 21, 9:44 pm, Todd Benson \ wrote: > > > On Nov 20, 2007 7:24 PM, RichardOnRails \> \> \ wrote: > > > > \> On Nov 20, 10:22 am, Harry Kakueki \ wrote: > > \> \> By the way, stop calling me Shirley. 🙂 > > \> \> And stop calling me Ryan. 🙂 > > > > \> \> Good luck, > > > > \> \> Harry > > \> Hi Harry, > > > > \> I apologize for the "Ryan" thing. Ryan was the first response on this > > \> thread and got mixed up. I don't know about the "Shirley" thing. > > > > Harry is quoting from the movie Airplane (1980) 🙂 > > > > Todd ---
**Author:** ![Jordan\_Callicoat](https://avatars.discourse-cdn.com/v4/letter/j/9de053/32.png) [@Jordan\_Callicoat](https://rubytalk.org/u/Jordan_Callicoat)\ **Post date:** [27 November 2007 03:35 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/33 "2007-11-27T03:35:00Z")
On Nov 26, 9:13 pm, RichardOnRails > Thanks. I'm running ruby 1.8.2 (2004-12-25) [i386-mswin32]. How can > I tell if it uses Oniguruma RE ver.5.6.0? You don't actually need oniguruma, it's the same syntax as class Regexp in ruby 1.8 (well, a few things don't work, but 99% does). Regards, Jordan ---
**Author:** ![Raul\_Parolari](https://avatars.discourse-cdn.com/v4/letter/r/49beb7/32.png) [@Raul\_Parolari](https://rubytalk.org/u/Raul_Parolari)\ **Post date:** [28 November 2007 07:25 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/34 "2007-11-28T07:25:23Z")
RichardOnRails wrote: > Thank you for your further support of my obstinacy �� Your help has > guided me to the solution I wanted. Your original one is succinct, > perhaps even elegant in that it decomposes the problem into two sub- > problems which admit of essentially one-line solutions. While I truly > appreciate that approach, I wanted to find a "natural" solution, > which is the one included below. Hi, Richard   you mention your 'obstinacy'... and indeed, you have found a way to implement with Regexps your original design (you did not fool me! :-); great ingenuity. However, as much as I am stunned by your progress (your original program at the top of this post and this one seem like Dante going from Inferno to Paradiso), I must be frank. I do not like building arrays to meet some 'maximum treshold', leaving portions of them empty; it just does not make me 'happy' (in the Matz/Ruby sense, do you understand?). Of course, it is just an array of 5 positions, but it does not matter; it is just echologically wrong for me. I however understand your feeling towards my solution (and the contrast you create with your 'natural one'); got it! but then I invite you to explore scan with \G; look at this, that may be doing something more 'natural': # \G 'anchors' start of next search to end of previous one re\_prefix = %r/\G (\d+ [.]?) /x input.each { |line| p line.scan(re\_prefix).flatten } Output: ["05"] ["1", "0"] ["2", "002", "1"] ["3", "15", "26", "37"] Small (1 line!), fast, precise: a beauty. It is not the complete solution as '\G scan' in Ruby does not allow you to change the regexp without interrupting the job (there are sad workarounds for it), so the job is not complete. The library StringScanner ('strscan') is of interest, as it solves this problem nicely (and is in C, so is fast). Perhaps, examine \G and/or StringScanner, and see if you can find a solution that meets what you are looking for, without (as seen from me) imperfections. Congrats for your progress (in 1 week!) Raul   Some people, when confronted with a problem, think:   "I know, I'll use regular expressions".   Now they have two problems.   Jamie Zawinski   :-) > **···** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Alex\_Young](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@Alex\_Young](https://rubytalk.org/u/Alex_Young)\ **Post date:** [26 November 2007 20:56 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/35 "2007-11-26T20:56:05Z")
RichardOnRails wrote: \ > Hi Alex, > > > abbreviation prefix to denote a semantic difference within a > > type, then that's (potentially) useful, in both Ruby and C: > >    us\_username = read\_unsafe\_input() > >    s\_username = sanitise(us\_username) > > I like that. > > > If it's denoting a class, > > then it's not something I can see as useful > > I like to know merely by inspection whether a referent denotes an > integer, a string, a hash or an array of such things. I'd like to > avoid "Syntax error" simply because I failed to include a to\_s, to\_i, > or whatever. You'll tend to find that types are much less relevant in Ruby than in C. The actual class of an object is much less important than the methods it responds to, and you won't get a syntax error unless the syntax is actually wrong; this won't be a problem with variables because of the lack of compile-time type checking. I've tried the method you're espousing myself, and it didn't actually help me at all. I found it just wasn't worth the effort. However, I'm more than willing to accept that it's a difference between your coding style and mine rather than any fundamental problem with the concept that made the difference. In terms of posting code here, the most important thing is to make it readable. Most people won't know what your hungarian prefixes mean, so they're just line noise to them. > **···** > > -- > Alex ---
**Author:** ![Raul\_Parolari](https://avatars.discourse-cdn.com/v4/letter/r/49beb7/32.png) [@Raul\_Parolari](https://rubytalk.org/u/Raul_Parolari)\ **Post date:** [26 November 2007 21:23 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/36 "2007-11-26T21:23:08Z")
RichardOnRails wrote: > I like to know merely by inspection whether a referent denotes an > integer, a string, a hash or an array of such things. I'd like to > avoid "Syntax error" simply because I failed to include a to\_s, to\_i, > or whatever. I really can't see why a prefixed lower-case letter > or two before a camel-case object name can create so much discussion > irrelevant to the question at hand. Richard,   I always found fascinating the issue of 'how we name things', and not only for philosophical reasons; personally I think that the horrendous amount of time spent to-day in what is called "Testing Dept" is due in part to problems like that. A bad and careless Naming methodology (when there is one!) leads (especially in a project where people share code) to subtle errors, flawed assumptions, and ultimately to errors (unfortunately, when there is somebody put in charge of the 'naming standards', he is often very politically correct, but not the brightest guy around, and the result is even worse than 'no standards'). One person who wrote something intelligent about this subject is Damian Conway in his book "Perl Best Practices" (ok, I will get the usual parochial boos for naming that language, but ok, life continues), specifically chapter 3 "Naming Conventions". Even if the examples are on Perl syntax, the substance goes beyond. He suggests something different than your approach; the name should indicate not so much the class/type, but the MEANING of the data structure; for example (of course I will not use Perl syntax, and avoid the examples that make sense for Perl only): # scalars running\_total games\_count # (rather than 'total','count') # booleans is\_valid has\_end\_tag loading\_finished # arrays events handlers unknowns # the iteration var event handler unknown # hashes title\_of count\_for sales\_from isbn\_from He even discusses the role of 'nouns' and 'adjectives' in names.. (a delight to read!). The emphasis is in the MEANING of the data, not on the 'class/type': do you see? but the objective is similar to yours: grant somebody looking at code of somebody else (translated: ourselves 6 months later!) at least a hope to vaguely understand what is going on! You may want to glance at it, if you find that approach of interest. Raul   Names are but noise and smoke,   obscuring heavenly light   Johann Wolfgang von Goethe, "Faust: Part I" > **···** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Richard3](https://avatars.discourse-cdn.com/v4/letter/r/b5a626/32.png) [@Richard3](https://rubytalk.org/u/Richard3)\ **Post date:** [28 November 2007 01:00 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/37 "2007-11-28T01:00:01Z")
> On Nov 26, 9:13 pm, RichardOnRails > > \> Thanks. I'm running ruby 1.8.2 (2004-12-25) [i386-mswin32]. How can > \> I tell if it uses Oniguruma RE ver.5.6.0? > > You don't actually need oniguruma, it's the same syntax as class > Regexp in ruby 1.8 (well, a few things don't work, but 99% does). > > Regards, > Jordan Hi Jordan, > You don't actually need oniguruma, it's the same syntax as class > Regexp in ruby 1.8 (well, a few things don't work, but 99% does). Great! Thank you very much for the Cheat Sheet. Best wishes, Richard > **···** > > On Nov 26, 10:32 pm, MonkeeSage \ wrote: ---
**Author:** ![Raul\_Parolari](https://avatars.discourse-cdn.com/v4/letter/r/49beb7/32.png) [@Raul\_Parolari](https://rubytalk.org/u/Raul_Parolari)\ **Post date:** [28 November 2007 07:40 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/38 "2007-11-28T07:40:41Z")
Just to correct the position of a parenthesis above: > re\_prefix = %r/\G (\d+ [.]?) /x   re\_prefix = %r/\G (\d+) [.]? /x Raul > **···** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Richard3](https://avatars.discourse-cdn.com/v4/letter/r/b5a626/32.png) [@Richard3](https://rubytalk.org/u/Richard3)\ **Post date:** [29 November 2007 02:45 UTC](https://rubytalk.org/t/false-positives-in-editing-data/42312/39 "2007-11-29T02:45:02Z")
Hi Raul, > \> re\_prefix = %r/\G (\d+ [.]?) /x I have learned something: I saw immediately that the mistyped version was not what you intended because the dots would have been captured. I applied your correction and things worked as advertised. > ... you have found a way to implement with Regexps your > original design (you did not fool me! :-); :BG > great ingenuity [snip] stunned by your progress Thanks for the compliments, but they're not merited in this respect: I wrote my first program circa 1955 (on paper only; no execution) after receiving a letter from a former high-school classmate announcing that he had encountered new-fangled machines at Princeton called "computers". He furthermore recounted their instruction set. I was hooked. After grinding out a degree from night-college and earning an NSF graduate fellowship in math, I finally got a job programming a real computer, which I continued until I retired a few years ago. > I must be frank. Absolutely. I've invited that, and am also impressed with your gracious approach. > I do not like building arrays to meet some 'maximum treshold', leaving portions of them empty; it just does not make me 'happy' (in the Matz/Ruby sense, do you understand?). Of course, it is just an array of 5 positions, but it does not matter; it is just echologically wrong for me. I acknowledge and share the aesthetic validity of your displeasure. > I however understand your feeling towards my solution (and the contrast you create with your 'natural one'); got it! but then I invite you to explore scan with \G; look at this, that may be doing something more 'natural': > # \G 'anchors' start of next search to end of previous one re\_prefix = %r/\G (\d+ [.]?) /x input.each { |line| p line.scan(re\_prefix).flatten } > Small (1 line!), fast, precise: a beauty. I agree fully! Of course I couldn't leave "well enough" alone, so here's my mod: input.each { |line| line.scan(re\_prefix).flatten.each { |e|     printf("%s ",e)}; puts } > Perhaps, examine \G and/or StringScanner, ... I took a fast look at ruby-doc.org/core/ ... looks good. Thanks > see if you can find a solution that meets what you are looking for, without (as seen from me) imperfections. Your latest approach suits my requirement (and taste) perfectly. I'm off now to continue work on the project I'm developing, which you might find interesting. Since it's off-topic, send me an email if you want details. (My email-address looks artificial in order to deter spammers, but I do have a mail box for it which I only check sporadically unless I anticipate legitimate email.) > Some people, when confronted with a problem, think:   "I know, I'll use regular expressions".   Now they have two problems. :BG Again, thank you and Best Wishes, Richard [Previous page](https://rubytalk.org/t/false-positives-in-editing-data/42312.md?page=1)