Problem converting a Matrix to Data Frame in R (R thinks all numeric types are factors)

Question

Hello! I am passing data from C# to R over a COM interface. When the data arrives in R it is housed in a 'Matrix'. Some of the functions that I use require that the data be inside a 'DataFrame' instead. I convert the data structure using

newDataFrame <- as.data.frame(oldMatrix)

The table of data reaches R just fine, once I make the conversion to the DataFrame however, it assumes all of my numeric data are factors!

So it turns: {34, 46, 90, 54, 69, 54} into {1, 2, 3, 4, 5, 4}

My data table DOES have factors in it though, so I just can't force the whole thing to be numeric. Is there any way around this? Note: I can't export the data as a CSV onto the filesystem and read it into R manually.

On a side note, the function I am using that requires a DataFrame is the 'Hmisc' package using

hist.data.frame(dataFrame)

this produces a frequency histogram for every column of data in the DataFram and arranges them in all in a grid pattern (quite nifty)!

Thanks! -Dave

Answer 1

I've had this problem before. You need to set stringsAsFactors=F when you read the data.

Now, you can convert individual variables/columns to factors (ie, with as.numeric() and the like), without worrying about how the numbers are treated.

Answer 2

I think you have mis-diagnosed the problem - all columns in a matrix must be of the same type, so this is likely to be where the problem arises, not the conversion to a data frame.