[R] Extraneous full stop in csv read

[David Winsemius]

> On Jun 28, 2017, at 4:30 PM, John <jwd at surewest.net> wrote:
> 
> I ran into a puzzling minor behaviour I would like to understand.
> Reading in a csv file, I find an extraneous "." after a column header,
> "in" [short for "inches"] thus, "in.". Is this due to "in" being
> reserved?  I initially blamed this on RStudio or to processing the data
> through LibreCalc. However, the same result occurs in a console R
> session.  Sending the file to the console via less reveals no strange
> characters in the first line.  The data is California statewide
> rainfall which was screen captured from the Western Regional Climate
> Center web site.
> 
> First 15 lines including header line:
> 
> "yr","mo","Data","in"
> 1895,1,8243,8.243
> 1895,2,2265,2.265
> 1895,3,2340,2.34
> 1895,4,1014,1.014
> 1895,5,1281,1.281
> 1895,6,58,0.058
> 1895,7,156,0.156
> 1895,8,140,0.14
> 1895,9,1087,1.087
> 1895,10,322,0.322
> 1895,11,1331,1.331
> 1895,12,2428,2.428
> 1896,1,7156,7.156
> 1896,2,712,0.712
> 1896,3,2982,2.982
> 
> File read in as follows:
> 
> x <- read.csv('DRI-mo-prp.csv', header = T)

If I change one of those other headers to "for", I also see the period-suffix appended, which supports your theory about reserved words being protected. If for some reason this were important to you, hten I'd suggest first looking at the code for make.names which in turn indicates that it's done with a .Internal call, so you'll need to look at the source code for the base-package.
-- 
David.
> 
> Structure:
> 
> str(x)
> 'data.frame':   1469 obs. of  4 variables:
> $ yr  : int  1895 1895 1895 1895 1895 1895 1895 1895 1895 1895 ...
> $ mo  : int  1 2 3 4 5 6 7 8 9 10 ...
> $ Data: int  8243 2265 2340 1014 1281 58 156 140 1087 322 ...
> $ in. : num  8.24 2.27 2.34 1.01 1.28 ...
> [note "in" is now "in."]
> 
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David Winsemius
Alameda, CA, USA