(Ted Harding) wrote:
>
> This happens also when you use C's fprintf and sprintf (at any rate
> in my gcc):
>
r's printing routines (e.g., print, sprintf, cat, anything else?) seem
to rely on the underlying c sprintf, with no prior r-implemented
rounding. hence they import into r whatever standards-related problems
may the c counterpart have.
> #include <stdio.h>
> #include <math.h>
>
why math.h?
> main(argc,argv) int argc; char **argv;
> {
> fprintf(stdout, "%.1f\n", 0.15);
> fprintf(stdout, "%.1f\n", 0.05);
> fprintf(stdout, "%.2f\n", 0.15);
> fprintf(stdout, "%.2f\n", 0.05);
> }
>
> cc -o testprint3 testprint3.c
> ./testprint
> 0.1
> 0.1
> 0.15
> 0.05
>
> (with similar output when printing a string formatted by sprintf).
>
indeed. i posted a similar example in reaction to the original 'excel
bug' response.
> So, in so far a R relies on the compiler's implementation of the
> *printf functions, this can hardly be put right withbout re-writing
> [g]cc!
it does (seems to), but probably shouldn't, if excel bugs are to be
avoided. however, passing the input from sprintf('%.1f', x) through
round to do the rounding would require some work to first parse the
format and decide the number of decimal digits. not that it's undoable.
vQ
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