[R] strange behaviour when subsetting a data.frame

[Eckstädt, Elisabeth]

Hello everyone,
I am experiencing a unfathomable benaviour of "subset" on a data.frame. This is a minimal reproducable example. The data.frame cosists only of one column, which contains 10 ascending values (from 0.1 to 1). Subsetting for 0.1 is working (gives me one row), subsetting for 0.3 gives me zero rows? Doing the same with values from 1 to 10 is working out well (as expected). 

Beimischung=seq(0.1,1,0.1)
man2=data.frame(Beimischung)
subset(man2, Beimischung==0.3)
#---> gives 0 rows
subset(man2, Beimischung==0.1)
---> gives one row (as expected)#

#also not working:

man2$Beimischung3=man2$Beimischung*10
subset(man2, Beimischung3==3)
--> gives 0 rows

Does anybody have a clue for me?
Thanks in advance
Regards
Elisabeth
_______________
Dipl.-Ing. Elisabeth Eckstädt
Member of Academic Staff & PhD Student
Technische Universität Dresden
Faculty of Mechanical Engineering
Institue of Power Engineering
Chair of Building Energy Systems and Heat Supply

Phone +49 351 463 34709
Fax +49 351 463 37076
Web http://tu-dresden.de/mw/iet/ew