Hi,
In R 3.4.0, the "Pattern Matching and Replacement" documentation that describes
regexec(), gregexpr(), etc. states that the "text" argument to regexec is a
character vector, "or an object which can be coerced by as.character to a
character vector":
regexec(pattern, text, ignore.case = FALSE, perl = FALSE,
fixed = FALSE, useBytes = FALSE)
x, text: a character vector where matches are sought, or an object
which can be coerced by as.character to a character vector.
Long vectors are supported.
However, in R 3.4.0, this coercion doesn't seem to automatically occur for the
text argument of regexec(), whereas it does for gregexpr(), regexpr(), etc:
============================================================
$ R --vanilla
R version 3.4.0 (2017-04-21) -- "You Stupid Darkness"
Copyright (C) 2017 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)
...
> text <- as.factor("foobar")
> regexec("foo", text)
Error in regexec("foo", text) : invalid 'text' argument
> regexec("foo", as.character(text))
> [[1]]
>
> [1] 1
attr(,"match.length")
[1] 3
attr(,"useBytes")
[1] TRUE
> gregexpr("foo", text)
> [[1]]
[1] 1
attr(,"match.length")
[1] 3
attr(,"useBytes")
[1] TRUE
============================================================
Is this a documentation issue, a bug in regexec(), or am I misunderstanding how
it's supposed to behave?
Thanks,
--
Nathan Weeks
IT Specialist
USDA-ARS Corn Insects and Crop Genetics Research Unit
Crop Genome Informatics Laboratory
Iowa State University
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