You need to line up the rows before you do the arithmetic. Check out ?merge
"rasanpreet" <rasanpreet.k...@gmail.com> wrote: > >hi guys..please help me with this >i am working on two data frames >one goes like this: >DF1 >Sample_id RepairHours Denatured Dose ZeroMean FourtyFiveMean NinetyMean >1 SDM071 0 1 B 60.5 19.0 45.0 >2 SDM071 1 1 B 46.0 23.0 42.5 >3 SDM071 2 1 B 52.5 24.0 40.0 >4 SDM071 3 1 B 42.0 21.5 45.0 >5 SDM053 0 1 B 66.5 28.5 56.5 >6 SDM053 1 1 B 47.0 29.0 47.5 >7 SDM053 2 1 B 52.0 31.0 44.0 >8 SDM053 3 1 B 36.0 34.0 41.5 >9 SDM059 0 1 B 47.5 41.5 29.0 >10 SDM059 1 1 B 47.0 36.0 35.0 >11 SDM059 2 1 B 41.5 42.0 32.5 >12 SDM059 3 1 B 46.5 41.5 32.0 > > >and the other one: >DF2 >SampleId RepairHours Denatured Dose_uM Day_0_Read1 Day_0_Read2 Day_45_Read1 >8 SDM071 0 1 C 124 120 >108 >9 SDM071 0 1 25 123 128 >77 >10 SDM071 0 1 50 132 138 >79 >11 SDM071 0 1 100 118 116 >68 >12 SDM071 0 1 200 125 146 >73 >20 SDM071 1 1 C 113 117 >113 >21 SDM071 1 1 25 108 115 >132 >22 SDM071 1 1 50 105 96 >94 >23 SDM071 1 1 100 101 101 >88 >24 SDM071 1 1 200 114 106 >89 >32 SDM071 2 1 C 143 136 >109 >33 SDM071 2 1 25 126 147 >110 >34 SDM071 2 1 50 109 122 >107 >35 SDM071 2 1 100 114 118 >89 >36 SDM071 2 1 200 118 128 >88 >44 SDM071 3 1 C 103 111 >116 >45 SDM071 3 1 25 108 105 >115 >46 SDM071 3 1 50 118 99 >88 >47 SDM071 3 1 100 98 103 >105 >48 SDM071 3 1 200 112 105 >96 >56 SDM053 0 1 C 214 208 >158 >57 SDM053 0 1 25 159 214 >178 >58 SDM053 0 1 50 170 169 >112 >59 SDM053 0 1 100 149 158 >124 >60 SDM053 0 1 200 201 171 >115 >68 SDM053 1 1 C 149 166 >120 >69 SDM053 1 1 25 145 134 >118 >70 SDM053 1 1 50 159 169 >130 >71 SDM053 1 1 100 113 126 >110 >72 SDM053 1 1 200 118 112 >120 > > >these are just part of the frames...... >i have to subtract the first five values of dataframe2 from one value from >dataframe1 >eg: subtract<-DF2$Day_0_Read1-DF1$ ZeroMean > > >if u notice the repair hours in both have to match...along with their id's. >i have tried this >zeroday_subtract1=DF1$Day_0_Read1 - DF2[DF1$RepairHours,]$ZeroMean >but it dosent work > > >please help me with this...i know its basic but i needhelp >thx in advance > > >-- >View this message in context: >http://r.789695.n4.nabble.com/how-to-compute-when-row-length-is-different-tp2538930p2538930.html >Sent from the R help mailing list archive at Nabble.com. > > [[alternative HTML version deleted]] > >______________________________________________ >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. --------------------------------------------------------------------------- Jeff Newmiller The ..... ..... Go Live... DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... Live: OO#.. Dead: OO#.. Playing Research Engineer (Solar/Batteries O.O#. #.O#. with /Software/Embedded Controllers) .OO#. .OO#. rocks...1k --------------------------------------------------------------------------- Sent from my phone. Please excuse my brevity. ______________________________________________ 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.