On Sep 22, 2015, at 3:00 PM, Therneau, Terry M., Ph.D. wrote:
> I have a csv file from an automatic process (so this will happen thousands of
> times), for which the first row is a vector of variable names and the second
> row often starts something like this:
>
> 5724550,"000202075214",2005.02.17,2005.02.17,"F", .....
>
> Notice the second variable which is
> a character string (note the quotation marks)
> a sequence of numeric digits
> leading zeros are significant
>
> The read.csv function insists on turning this into a numeric. Is there any
> simple set of options that
> will turn this behavior off? I'm looking for a way to tell it to "obey the
> bloody quotes" -- I still want the first, third, etc columns to become
> numeric. There can be more than one variable like this, and not always in
> the second position.
The last part about not knowing which col might be an issue might require
inputting everything with character class, but if there is a way to pass in a
colClasses argument this might help:
> read.csv(text='5724550,"000202075214",2005.02.17,2005.02.17,"F"',
> stringsAsFactors=FALSE, header=FALSE, colClasses=c("numeric",
> rep("character", 4)))
V1 V2 V3 V4 V5
1 5724550 000202075214 2005.02.17 2005.02.17 F
Or you can create a class with an As method:
> setClass('myChar')
> setAs('character', 'myChar', def=function(from, to ) to <- I(from))
> read.csv(text='5724550,"000202075214",2005.02.17,2005.02.17,"F"',
> stringsAsFactors=FALSE, header=FALSE, colClasses=c("numeric",
> rep('myChar',4)) )
V1 V2 V3 V4 V5
1 5724550 000202075214 2005.02.17 2005.02.17 F
(Neither of the third or fourth columns makes sense as a numeric, so now
illustrating coercion to Date.)
> setClass('dotDate')
> setAs('character', 'dotDate', def=function(from, to ) to <- as.Date(from,
> "%Y.%m.%d") )
> read.csv(text='5724550,"000202075214",2005.02.17,2005.02.17,"F"',
> stringsAsFactors=FALSE, header=FALSE, colClasses=c("numeric", "character",
> rep('dotDate',2), "character") )
V1 V2 V3 V4 V5
1 5724550 000202075214 2005-02-17 2005-02-17 F
>
> This happens deep inside the httr library; there is an easy way for me to add
> more options to the read.csv call but it is not so easy to replace it with
> something else.
>
> Terry T
>
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David Winsemius
Alameda, CA, USA
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