R rbind error row.names duplicates not allowed

Question

There are other issues here addressing the same question, but I don't realize how to solve my problem based on it. So, I have 5 data frames that I want to merge rows in one unique data frame using rbind, but it returns the error:

"Error in row.names<-.data.frame(*tmp*, value = value) : 'row.names' duplicated not allowed In addition: Warning message: non-unique values when setting 'row.names': ‘1’, ‘10’, ‘100’, ‘1000’, ‘10000’, ‘100000’, ‘1000000’, ‘1000001 [....]"

The data frames have the same columns but different number of rows. I thought the rbind command took the first column as row.names. So tried to put a sequential id in the five data frames but it doesn't work. I've tried to specify a sequential row names among the data frames via row.names() but with no success too. The merge command is not an option I think because are 5 data frames and successive merges will overwrite precedents. I've created a new data frame only with ids and tried to join but the resulting data frame don't append the columns of joined df.

Follows an extract of df 1:

  id    image     power     value pol class
1  1 tsx_sm_hh 0.1834515 -7.364787  hh    FR
2  2 tsx_sm_hh 0.1834515 -7.364787  hh    FR
3  3 tsx_sm_hh 0.1991938 -7.007242  hh    FR
4  4 tsx_sm_hh 0.1991938 -7.007242  hh    FR
5  5 tsx_sm_hh 0.2079365 -6.820693  hh    FR
6  6 tsx_sm_hh 0.2079365 -6.820693  hh    FR
[...]
1802124 1802124 tsx_sm_hh 0.1991938 -7.007242  hh    FR  

The four other df's are the same structure, except the 'id' columns that don't have duplicated numbers among it. 'pol' and 'image' columns are defined as levels. and all.pol <- rbind(df1,df2,df3,df4,df5) return the this error of row.names duplicated.

Any idea?

Thanks in advance

Answer 1

I had the same error recently. What turned out to be the problem in my case was one of the attributes of the data frame was a list. After casting it to basic object (e.g. numeric) rbind worked just fine.

By the way row name is the "row numbers" to the left of the first variable. In your example, it is 1, 2, 3, ... (the same as your id variable).

You can see it using rownames(df) and set it using rownames(df) <- name_vector (name_vector must have the same length as df and its elements must be unique).