[R] read.table: how to ignore errors?

[Sam Steingold]

> * William Dunlap <jqhaync at gvopb.pbz> [2012-01-24 21:47:39 +0000]:
>
>> >> Oh, yeah, a reproducible example:
>> >>
>> >> read.csv from
>> >> =====
>> >> a,b
>> >> 1,2
>> >> 3,4
>> >> 5,,6
>> >> 7,8
>> >> =====
>> >> I want to be able to extract the data frame
>> >>   a b
>> >> 1 1 1
>   The previous line should be '1 1 2', right?

of course, thanks!

>> >> 2 3 4
>> >> 3 7 8
>
> Have you tried using count.fields to remove the lines
> in the file with the wrong number of fields?  E.g.,
>
>> tf <- tempfile()
>> cat(c("a,b", "1,2", "3,4", "5,,6", "7,8"), file=tf, sep="\n")
>> # following will fail
>> read.table(tf, sep=",", header=TRUE)
> Error in scan(file, what, nmax, sep, dec, quote, skip, nlines, na.strings,  :
>   line 1 did not have 3 elements
>> # following reads lines with 2 fields only
>> textLines <- readLines(tf)
>> counts <- count.fields(textConnection(textLines), sep=",")
>> read.table(text=textLines[counts == 2], header=TRUE, sep=",")
>   a b
> 1 1 2
> 2 3 4
> 3 7 8

sounds good, thanks a lot!

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