[datatable-help] leading spaces on column names from CSV file

[Matt Dowle]

Hi Jim,
Ok yes good idea.   The roots of that are due to data.table allows 
leading and trailing spaces (and all special characters) in column 
names.  The confusion that  by="a, b, c" doesn't work due to the spaces, 
due to column name " b" being different to "b".   But for fread that 
doesn't make sense and it should drop the leading spaces by default, 
yes.   I've added this to the top of fread.c where I'm logging the fread 
ToDos.
Thanks, Matt


On 22/01/14 16:21, jholtman wrote:
> I have a CSV file that I had been reading with 'read.csv' and it turns out
> that the column names had leading spaces in some instances, but read.csv
> would remove them.
>
> I tried to read the file with fread and it was keeping the leading spaces.
> Here is dump of the session:
>
>> positXY <- read.csv(positionFile, as.is = TRUE)
>>
>>
>> str(positXY)
> 'data.frame':   12 obs. of  8 variables:
>   $ ieee           : chr  "1972cd01004b1200" "6375cd01004b1200"
> "5875cd01004b1200" "1972cd01004b1200" ...
>   $ startTime      : chr  "13:46" "13:46" "13:46" "13:53" ...  # no leading
> space on next three
>   $ endTime        : chr  "13:51" "13:51" "13:51" "13:58" ...
>   $ x              : int  65 65 65 65 65 65 65 65 65 65 ...
>   $ y              : int  45 45 45 45 45 45 45 45 45 45 ...
>   $ z              : num  3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 ...
>   $ deviceDirection: chr  "east" "west" "north" "south" ...
>   $ test.          : logi  NA NA NA NA NA NA ...
>> positXY <- fread(positionFile)
>>
>> str(positXY)
> Classes ‘data.table’ and 'data.frame':  12 obs. of  8 variables:
>   $ ieee           : chr  "1972cd01004b1200" "6375cd01004b1200"
> "5875cd01004b1200" "1972cd01004b1200" ...
>   $  startTime     : chr  "13:46" "13:46" "13:46" "13:53" ...  # leading
> space on next three
>   $  endTime       : chr  "13:51" "13:51" "13:51" "13:58" ...
>   $  x             : int  65 65 65 65 65 65 65 65 65 65 ...
>   $ y              : int  45 45 45 45 45 45 45 45 45 45 ...
>   $ z              : num  3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 ...
>   $ deviceDirection: chr  "east" "west" "north" "south" ...
>   $  test#         : int  NA NA NA NA NA NA NA NA NA NA ...
>   - attr(*, ".internal.selfref")=<externalptr>
>> sessionInfo()
> R version 3.0.2 (2013-09-25)
> Platform: x86_64-w64-mingw32/x64 (64-bit)
>
> locale:
> [1] LC_COLLATE=English_United States.1252
> [2] LC_CTYPE=English_United States.1252
> [3] LC_MONETARY=English_United States.1252
> [4] LC_NUMERIC=C
> [5] LC_TIME=English_United States.1252
>
> attached base packages:
> [1] stats     grDevices utils     datasets  graphics  methods
> [7] base
>
> other attached packages:
> [1] data.table_1.8.10 bitops_1.0-6
>
> loaded via a namespace (and not attached):
> [1] tools_3.0.2
>
>
> Is it possible to have the leading spaces removed automatically, or via a
> parameter?
>
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/leading-spaces-on-column-names-from-CSV-file-tp4683986.html
> Sent from the datatable-help mailing list archive at Nabble.com.
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