Hello
I have a data set like below:
plate.id well.id Group HYB rlt1
1 P1 A1 Control SKOV3hyb 0.190
2 P1 A2 Control SKOV3hyb 0.210
3 P1 A3 Control SKOV3hyb 0.205
4 P1 A4 Control SKOV3hyb 0.206
5 P1 A5 Control SKOV3hyb 0.184
385 P1 A1 ovca SKOV3hyb 0.184
386 P1 A2 ovca SKOV3hyb 0.229
387 P1 A3 ovca SKOV3hyb 0.214
388 P1 A4 ovca SKOV3hyb 0.226
389 P1 A5 ovca SKOV3hyb 0.217
390 P1 A6 ovca SKOV3hyb 0.207
each plate.id contains 384 readings for Group=="Control" and the same
plate.id will contain 384 readings for Group=='ovca' to give a total of 768
values for P1 and so on for other plate ID's. I have to take the subtract
the values of rlt1 colum between the two groups based on Plate ID.
currently I am using
> newdat2$diff<-(newdat2[1:5,5]-newdat2[6:10,5])/newdat2[1:5,5]*100
> newdat2
plate.id well.id Group HYB rlt1 diff
1 P1 A1 Control SKOV3hyb 0.190 3.157895
2 P1 A2 Control SKOV3hyb 0.210 -9.047619
3 P1 A3 Control SKOV3hyb 0.205 -4.390244
4 P1 A4 Control SKOV3hyb 0.206 -9.708738
5 P1 A5 Control SKOV3hyb 0.184 -17.934783
385 P1 A1 ovca SKOV3hyb 0.184 3.157895
386 P1 A2 ovca SKOV3hyb 0.229 -9.047619
387 P1 A3 ovca SKOV3hyb 0.214 -4.390244
388 P1 A4 ovca SKOV3hyb 0.226 -9.708738
389 P1 A5 ovca SKOV3hyb 0.217 -17.934783
I have tried
apply(newdat2, 1, function(x) tapply(x, plate.id,
newdat2$Control-newdat2$ovca)))
I am looking for a more simple way to calculate the percent difference
between the each value (based on well.id) for the two groups for 100's of
plate.ids.
I would appreciate help in getting this solved.
Thanks
--
View this message in context:
http://r.789695.n4.nabble.com/subtraction-based-on-two-groups-in-a-dataframe-tp2716104p2716104.html
Sent from the R help mailing list archive at Nabble.com.
______________________________________________
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.
