If you have unicode strings, you may need to do even more because there are often multiple ways of representing the same glyph. I made a little demo at http://rpubs.com/hadley/unicode-normalisation, since any unicode characters are likely to get mangled by email.
Hadley On Fri, Jul 18, 2014 at 11:32 AM, William Dunlap <wdun...@tibco.com> wrote: >>>"abc" == "abc " >> [1] FALSE > > R does no interpretation of strings when doing comparisons so you do > have do your own canonicalization. That may involve removing > trailing, leading, or all white space or punctuation, converting to > lower or upper case, mapping nicknames to official names, trimming to > a fixed number of characters, etc. > > Bill Dunlap > TIBCO Software > wdunlap tibco.com > > > On Fri, Jul 18, 2014 at 9:17 AM, John McKown > <john.archie.mck...@gmail.com> wrote: >> Well, this was a shock to me. And I don't really see any documentation >> about it, but perhaps I just can't see it. >> >>>"abc" == "abc " >> [1] FALSE >> >> I guess that I thought of strings in R like I do is some other >> languages where the shorter value is padded with blanks to the length >> of the longer value, then compared. I.e. that trailing blanks didn't >> matter. >> >> The best solution that I have found is to use the str_trim() function >> from the stringr to remove all the trailing blanks after I get the >> data from the SQL data base. I cannot change the SQL schema to make >> the column a varchar instead of a char column. It is a vendor DB. And >> I don't know an ANSI SQL standard way to remove trailing blanks in the >> SELECT command. PostgreSQL has a "trim(trailing ' ' from column)', but >> MS-SQL upchucks on that syntax. >> >> -- >> There is nothing more pleasant than traveling and meeting new people! >> Genghis Khan >> >> Maranatha! <>< >> John McKown >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. -- http://had.co.nz/ ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
