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I'm trying to load a file that contains integers and float data. I'm at a loss as to why R will read one of the columns as a character field.
> df <- read.table( 'C:\\temp\\test.tab' ,
+ sep = '\t' , header = TRUE , stringsAsFactors = FALSE , dec="." )
> str(df)
'data.frame': 7 obs. of 5 variables:
$ A: int 0 0 0 0 1 0 0
$ B: int 1431 2097 2712 24821 27359 41165 49221
$ C: int 0 0 0 0 0 0 0
$ D: chr "7" "26.950000762939453" "57.95000076293945" "21" ...
$ E: int 1 2 3 4 5 6 7
A B C D E
0 1431 0 7 1
0 2097 0 26.950000762939453 2
0 2712 0 57.95000076293945 3
0 24821 0 21 4
1 27359 0 57.900001525878906 5
0 41165 0 33.95000076293945 6
0 49221 0 28.950000762939453 7
> R.version
_
platform x86_64-w64-mingw32
arch x86_64
os mingw32
system x86_64, mingw32
status
major 3
minor 1.0
year 2014
month 04
day 10
svn rev 65387
language R
version.string R version 3.1.0 (2014-04-10)
nickname Spring Dance
973
It's likely because they were originally factor s. You need as. numeric(as. character(........))
To convert character to numeric in R, use the as. numeric() function. The as. numeric() is a built-in R function that creates or coerces objects of type “numeric”.
Data Visualization using R Programming To convert columns of an R data frame from integer to numeric we can use lapply function. For example, if we have a data frame df that contains all integer columns then we can use the code lapply(df,as. numeric) to convert all of the columns data type into numeric data type.
Convert character to numeric. To convert character values to numeric values, use the INPUT function. new_variable = input(original_variable, informat.); The informat tells SAS how to interpret the data in the original character variable.
This probably deserves a genuine answer that we can point to, so....
The behavior of type.convert was altered in R 3.1.0 (and, read below, will be largely reverted to its pre-3.1.0 behavior in R 3.1.1):
As from R 3.1.0, where converting inputs to numeric or complex would result in loss of accuracy they are returned as strings (for as.is = TRUE) or factors.
This created a fairly significant ruckus on the r-devel mailing list. The beginning of the relevant (and long) thread is here.
As Ben mentioned above, one of the results of that discussion is that the default behavior was restored in the development version for a subsequent release.
In the short term if you know which columns will be affected you can always use colClasses. Otherwise you'd have to modify your code to check the results of read.table and convert things yourself, I guess.
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