[R] strange output with merge function

[Jeff Newmiller]

My guess would be that your key columns are factors with different levels. You have to be very careful manipulating factors... I recommend using character data until you are ready to do analysis steps that need factors. You may be able to resolve this by importing your data with the as.is=TRUE or stringsAsFactors=FALSE depending what functions you are using (read the help for your input function).

On December 3, 2019 10:02:45 AM PST, Ana Marija <sokovic.anamarija using gmail.com> wrote:
>Hi,
>
>I have two data frames like this:
>
>> head(a)
>               V1    V2     V3     V4 V5   V6      V7          V8    V9
> V10
>1: ENSG00000272636 chr17 181637 181636  - 4924 -769472   rs7216126
>chr17
>951108
>2: ENSG00000273172 chr17 191588 191587  - 4978   40553  rs62053745
>chr17
>151035
>3: ENSG00000273172 chr17 191588 191587  - 4978   39501  rs77383171
>chr17
>152087
>4: ENSG00000273172 chr17 191588 191587  - 4978   38817  rs34245596
>chr17
>152771
>5: ENSG00000273172 chr17 191588 191587  - 4978   38580 rs112513622
>chr17
>153008
>6: ENSG00000273172 chr17 191588 191587  - 4978   37794   rs8069278
>chr17
>153794
>      V11         V12       V13 V14          V15  V16
>1: 951108 4.03837e-05  0.429720   1 6.967229e-05 TRUE
>2: 151035 1.42190e-08 -0.488594   0 7.139876e-05 TRUE
>3: 152087 1.76913e-09 -0.664469   0 7.139876e-05 TRUE
>4: 152771 2.04442e-08 -0.479176   0 7.139876e-05 TRUE
>5: 153008 6.46268e-07 -0.768610   0 7.139876e-05 TRUE
>6: 153794 1.95944e-08 -0.480011   0 7.139876e-05 TRUE
>
>
>> head(f)
>            V8
>1:  rs12940868
>2:   rs4383187
>3:   rs4404112
>4:   rs7214091
>5:  rs35871790
>6: rs112532541
>
>I am trying to merge with:
>
>m=merge(a,f,by="V8")
>
>but I am getting this output where column on which I am merging V8 is
>replaced with number 17...
>
>> head(m)
>V8              V1    V2     V3     V4 V5   V6    V7    V9    V10   
>V11
>1: 17 ENSG00000273172 chr17 191588 191587  - 4978  1108 chr17 190480
>190480
>2: 17 ENSG00000273172 chr17 191588 191587  - 4978  1108 chr17 190480
>190480
>3: 17 ENSG00000273172 chr17 191588 191587  - 4978  1108 chr17 190480
>190480
>4: 17 ENSG00000262061 chr17 331206 331205  + 5858 24653 chr17 355858
>355858
>5: 17 ENSG00000262061 chr17 331206 331205  + 5858 24653 chr17 355858
>355858
>6: 17 ENSG00000262061 chr17 331206 331205  + 5858 24653 chr17 355858
>355858
>           V12       V13 V14          V15  V16
>1: 8.23430e-09 -0.511644   0 7.139876e-05 TRUE
>2: 8.23430e-09 -0.511644   0 7.139876e-05 TRUE
>3: 8.23430e-09 -0.511644   0 7.139876e-05 TRUE
>4: 5.46479e-05 -0.329785   0 5.962828e-05 TRUE
>5: 5.46479e-05 -0.329785   0 5.962828e-05 TRUE
>6: 5.46479e-05 -0.329785   0 5.962828e-05 TRUE
>
>Please advise,
>Thanks
>Ana
>
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>
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-- 
Sent from my phone. Please excuse my brevity.