You can read CSV files into R separately, and use the gene IDs as rownames of data frame, then you can use cbind to merge two data frame.

R also has a merge function that is useful, and you can merge by gene ID.

Hello I used merge command, but I got this error message, any help or suggestion

> CP1.df <- read.csv(file.choose(), header = TRUE, sep = ",")
> CP2.df <- read.csv(file.choose(), header = TRUE, sep = ",")
> X=merge(CP1.df,CP2.df)
Error: cannot allocate vector of size 4.9 Gb
In addition: Warning messages:
1: In expand.grid(seq_len(nx), seq_len(ny)) :
  Reached total allocation of 20388Mb: see help(memory.size)
2: In expand.grid(seq_len(nx), seq_len(ny)) :
  Reached total allocation of 20388Mb: see help(memory.size)
3: In expand.grid(seq_len(nx), seq_len(ny)) :
  Reached total allocation of 20388Mb: see help(memory.size)
4: In expand.grid(seq_len(nx), seq_len(ny)) :
  Reached total allocation of 20388Mb: see help(memory.size)
>

check join in bash

Hello I got the figured out how to solve it, and I am sharing it with you

exporttab <- merge(x=dwd_nogap, y=dwd_gap, by.x='x1', by.y='x2', fill=-9999), and it was very useful.