[Rcpp-devel] Bug: replace_last()

[Masaki Tsuda]

Hi, Quang

I confirmed that the bug was fixed.
Thank you for coping with the problem.

--------
// [[Rcpp::export]]
void rcpp_string(){

  String s("AABCDABCDA");
  Rcout << "replace_all()\n";
  Rcout << s.replace_all("AB", "ab").get_cstring()  << "\n";
  Rcout << "\n";

  s="AABCDABCDA";
  Rcout << "replace_first()\n";
  Rcout << s.replace_first("AB", "ab").get_cstring() << "\n";
  Rcout << "\n";

  s="AABCDABCDA";
  Rcout << "replace_last()\n";
  Rcout << s.replace_last("AB", "ab").get_cstring()  << "\n";
  Rcout << "\n";

}
---------
> rcpp_string()
replace_all()
AabCDabCDA

replace_first()
AabCDABCDA

replace_last()
AABCDabCDA


-------------------------------------------------------------------

     Masaki Tsuda
     E-mail : teuder at gmail.com

2016-05-17 12:03 GMT+09:00 Qiang Kou <qkou at umail.iu.edu>:

> Hi, Masaki,
>
> Please try the latest version on github. It should fix this bug.
>
> KK
>
> On Mon, May 16, 2016 at 9:42 PM, <teuder at gmail.com> wrote:
>
>> Hi, Kevin and Qiang.
>>
>> After I sent my first post, I realized the problem as you pointed out.
>>
>> The problem can be resolved by replacing replace_first() and
>> replace_last() to find() and rfind().
>>
>> -------------------
>> inline String& replace_first(const char* s, const char* news) {
>>    RCPP_STRING_DEBUG_2("String::replace_first(const char* = '%s' , const
>> char* = '%s')", s, news);
>>    if (is_na()) return *this;
>>    setBuffer();
>>    size_t index = buffer.find(s);
>>    //size_t index = buffer.find_first_of(s);
>>    if (index != std::string::npos) buffer.replace(index, strlen(s), news);
>>    valid = false;
>>    return *this;
>> }
>>
>> inline String& replace_last(const char* s, const char* news) {
>>    RCPP_STRING_DEBUG_2("String::replace_last(const char* = '%s' , const
>> char* = '%s')", s, news);
>>    if (is_na()) return *this;
>>    setBuffer();
>>    size_t index = buffer.rfind(s);
>>    //size_t index = buffer.find_last_of(s);
>>    if (index != std::string::npos) buffer.replace(index, strlen(s), news);
>>    valid = false;
>>    return *this;
>> }
>> -------------------
>> > rcpp_string()
>> replace_all()
>> AabCDabCDA
>>
>> replace_first()
>> AabCDABCDA
>>
>> replace_last()
>> AABCDabCDA
>> -------------------
>>
>> Regards
>>
>> Masaki
>>
>>
>>
>> Masaki Tsuda
>> teuder at gmail.com
>>
>> 2016/05/17 5:57、Qiang Kou <qkou at umail.iu.edu> のメッセージ:
>>
>> Yes, Kevin,
>>
>> I think we need something like
>>
>> size_t index = std::distance(buffer.begin(), std::search(buffer.begin(),
>> buffer.end(), s.begin(), s.end()));
>>
>> KK
>>
>> On Mon, May 16, 2016 at 2:04 PM, Kevin Ushey <kevinushey at gmail.com>
>> wrote:
>>
>>> Thanks -- it looks to me like there is something more fundamentally
>>> wrong with the 'replace_first' and 'replace_last' methods; ie, I don't
>>> think we want to be using 'find_first_of' and 'find_last_of'
>>> functions.
>>>
>>> Ie, when writing
>>>
>>>     string.replace_first("foo", "bar");
>>>
>>> I imagine we want to replace the first occurrence of 'foo' with 'bar',
>>> and not the first discovered character of 'f' and 'o'.
>>>
>>> A simple repro for the bogus behavior:
>>>
>>> #include <Rcpp.h>
>>> using namespace Rcpp;
>>>
>>> // [[Rcpp::export]]
>>> String replace() {
>>>   String foo("abba");
>>>   return foo.replace_first("ba", "BA");
>>> }
>>>
>>> /*** R
>>> replace()
>>> */
>>>
>>> gives
>>>
>>> > replace()
>>> [1] "BAba"
>>>
>>> which is I doubt what anyone would expect.
>>>
>>> On Sun, May 8, 2016 at 6:14 AM, 津田真樹 <teuder at gmail.com> wrote:
>>> > I find a bug in String::replace_last().
>>> >
>>> > I can reproduce the bug with the following code.
>>> > (I also showed output of replace_first and replace_all for comparison.)
>>> >
>>> >
>>> > =============
>>> > // [[Rcpp::export]]
>>> > void rcpp_string(){
>>> >
>>> >     String s("abcdabcd");
>>> >     Rcout << "replace_first()\n";
>>> >     Rcout << s.replace_first("ab", "AB").get_cstring() << "\n";
>>> >     Rcout << "\n";
>>> >
>>> >     s="abcdabcd";
>>> >     Rcout << "replace_last()\n";
>>> >     Rcout << s.replace_last("ab", "AB").get_cstring()  << "\n";
>>> >     Rcout << "\n";
>>> >
>>> >     s="abcdabcd";
>>> >     Rcout << "replace_all()\n";
>>> >     Rcout << s.replace_all("ab", "AB").get_cstring()  << "\n";
>>> >     Rcout << "\n";
>>> > }
>>> > =============
>>> >
>>> > output
>>> > =============
>>> > replace_first()
>>> > ABcdabcd
>>> >
>>> > replace_last()
>>> > abcdaABd
>>> >
>>> > replace_all()
>>> > ABcdABcd
>>> > =============
>>> >
>>> >
>>> > I also tried to fix the bug with following code. And the bug seems to
>>> be fixed.
>>> >
>>> > =============
>>> > inline String& replace_last(const char* s, const char* news) {
>>> >     RCPP_STRING_DEBUG_2("String::replace_last(const char* = '%s' ,
>>> const char* = '%s')", s, news);
>>> >     if (is_na()) return *this;
>>> >     setBuffer();
>>> >     //size_t index = buffer.find_last_of(s);
>>> >     size_t index = buffer.find_last_of(s) - (strlen(s)-1);
>>> >     Rcout << "A" << index << "\n";
>>> >     if (index != std::string::npos) buffer.replace(index, strlen(s),
>>> news);
>>> >     valid = false;
>>> >     return *this;
>>> > }
>>> > =============
>>> >
>>> > output
>>> > =============
>>> > replace_first()
>>> > ABcdabcd
>>> >
>>> > replace_last()
>>> > abcdABcd
>>> >
>>> > replace_all()
>>> > ABcdABcd
>>> > =============
>>> >
>>> >
>>> > Mac OS 10.10.5
>>> > R version 3.2.3
>>> > Rcpp 0.12.4
>>> >
>>> >
>>> > _______________________________________________
>>> > Rcpp-devel mailing list
>>> > Rcpp-devel at lists.r-forge.r-project.org
>>> >
>>> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
>>> _______________________________________________
>>> Rcpp-devel mailing list
>>> Rcpp-devel at lists.r-forge.r-project.org
>>> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
>>>
>>
>>
>>
>> --
>> Qiang Kou
>> qkou at umail.iu.edu
>> School of Informatics and Computing, Indiana University
>>
>>
>
>
> --
> Qiang Kou
> qkou at umail.iu.edu
> School of Informatics and Computing, Indiana University
>
>
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