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Column of explicitly quoted empty strings parsed as logical NA vector #5325

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jwimberl opened this issue Feb 4, 2022 · 2 comments
Open

Column of explicitly quoted empty strings parsed as logical NA vector #5325

jwimberl opened this issue Feb 4, 2022 · 2 comments
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@jwimberl
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jwimberl commented Feb 4, 2022 •
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Let test.csv be the file with contents

col
""
""
""

This is unambiguously a column of empty strings, yet data.table::fread("test.tsv") parses this as a logical class vector with NA values (and, maybe not unexpectedly, no setting of na.strings changes this since the column isn't getting parsed as strings in the first place). As long as one non-empty string is added into the column, e.g.

col
hotdog
""
""
""

then data.table::fread("test.tsv") correctly identifies this as a string column and parses it into a character vector with one non-empty, 3 empty, and 0 NA values.

Package data.table version 1.14.2, running on RedHat linux, with R version 3.6.0.
@ben-schwen
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I don't consider your example with fread(text='col\n""\n""\n') as unambiguous.

What is in your opinion the intended output of fread(text='col\n"1"\n""\n')?

@zoushucai
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I also encountered this issue. Setting na. strings doesn't seem to work, I need to treat "" as NA

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@zoushucai @ben-schwen @jwimberl