fread suggests fill for dropped column
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Assessment
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Newbie friendliness
- 45/100
Research direction
Start by reproducing the two examples with fread, using drop=3 and colClasses=list(NULL=3). Inspect fread's handling of column-name and data-column counts when a column is excluded. Done means the dropped column no longer triggers the fill warning, while the resulting data remains x and y.
Written by the indexing model from the issue text.
Description
Hi all!
Today I was using fread, on some data with one more column name than there is data, and I observed the following warning, which I think is a false positive. I would have expected no warning, because I told fread to drop the last column. Is this a bug?
> fread("x,y,z\n1,2",drop=3)
x y
<int> <int>
1: 1 2
Warning message:
In fread("x,y,z\n1,2", drop = 3) :
Detected 3 column names but the data has 2 columns. Filling rows automatically. Set fill=TRUE explicitly to avoid this warning.
> fread("x,y,z\n1,2",colClasses=list(NULL=3))
x y
<int> <int>
1: 1 2
Warning message:
In fread("x,y,z\n1,2", colClasses = list(`NULL` = 3)) :
Detected 3 column names but the data has 2 columns. Filling rows automatically. Set fill=TRUE explicitly to avoid this warning.
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