Merge r brings error “'by' must specify uniquely valid columns”

Question

R doesn\'t like me today...

I have two tables asembled via cbind(). Tab 1 (dwd_nogap) is

  x1                 col1_x1       col2_x1          


        

Answer 1

Rather give names of the column on which you want to merge:

exporttab <- merge(x=dwd_nogap, y=dwd_gap, by.x='x1', by.y='x2', fill=-9999)