[R] Adding Column to a Data Frame

Lauren O'Connell locon833 at gmail.com
Wed Mar 11 17:01:59 CET 2015

I am trying to add a column with data to a data frame that already has
information but am getting this error:

> rich.stats4 = merge(rich.stats,Location,Month,by="X.SampleID")
Error in fix.by(by.x, x) :
  'by' must specify one or more columns as numbers, names or logical

I have two separate data frames that contain my sample names with location
and with month:

#Create data frame of all sample names and month sample was taken

Month =


#Create data frame of all samples names and location of sample

Location =


I was able to add my "MonthSampleTaken" variable by using this command:

>rich.stats2 = merge(rich.stats, Month,by="X.SampleID")

> head(rich.stats2)

  X.SampleID    mean       sd MonthSampleTaken

1      PE101 1421.34 19.44961         February

2      PE102 1336.24 25.43882         February

3      PE104 1418.75 21.92889            March

4      PE105 1331.03 20.55712            March

5      PE107 1320.21 20.91942            March

6      PE108 1328.41 20.49247            March

I now want to add my sample site location, but can't figure out how to do
this. Any help would be greatly appreciated.



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