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Using fread, how to read CSV file which contains row and column names. I tried following but it is not reading the row and column names properly.
The csv file looks like (where C1,C2,C3 are column names and r1, r2, r3 are row names)
input = ",C1,C2,C3
r1,A,B,C
r2,1,3,5
3,2,4,6"
I use function
require(data.table)
fread(input,header = TRUE)
which give
r1 A B C
1: r2 1 3 5
2: 3 2 4 6
How can I properly read CSV using fread?
278
We're able to successfully import the CSV file using the fread() function. Note: We used double backslashes (\\) in the file path to avoid a common import error. Notice that we didn't have to specify the delimiter either since the fread() function automatically detected that it was a comma.
I understand that fread() should be faster than read. csv() because it tries to first read rows into memory as character and then tries to convert them into integer and factor as data types. On the other hand, fread() simply reads everything as character.
Use `fread()` to read a csv/tsv with row names (e.g. one created with `write.
Method 1: Using read. table() function. In this method of only importing the selected columns of the CSV file data, the user needs to call the read. table() function, which is an in-built function of R programming language, and then passes the selected column in its arguments to import particular columns from the data.
You should submit a bug report.
Here is a work-around:
colnames <- strsplit(readLines(textConnection(input), n=1), ",")[[1]]
colnames[1] <- "rownames"
setnames(DT <- fread(input, skip=1, header=FALSE), colnames)
DT
# rownames C1 C2 C3
#1: r1 A B C
#2: r2 1 3 5
#3: 3 2 4 6
As you should know, data.table doesn't support rownames.
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