[R] strings

Kurt Hornik Kurt.Hornik at ci.tuwien.ac.at
Wed Oct 4 09:02:25 CEST 2000

>>>>> Martin Maechler writes:

>>>>> "KH" == Kurt Hornik <Kurt.Hornik at ci.tuwien.ac.at> writes:
>>>>> Richard Rowe writes:
>>> I am attempting to analyse some behaviour sequence data.  The input is
>>> an alphabetic string "ASDFGH ... ".  I wish to start at one end of the
>>> string, peel off each character, and convert to an integer to develop
>>> transition matrices etc. My blundering through the ref manual hasn't
>>> produced any light.

>>> Can this be done easily in R or should I pre-process?

>>> I recollect an item similar to this on R-help around 6 mo ago but I
>>> can't find it in the archive. If there is such an article can someone
>>> please send me the date and I will track it down,

KH> Richard,

KH> Not sure what precisely you need ... if it is about converting a string
KH> to a vector of characters, you could use

R> x <- "ASDFGH"
R> x
KH> [1] "ASDFGH"
R> unlist(strsplit(x, NULL))
KH> [1] "A" "S" "D" "F" "G" "H"

KH> and proceed from there.

> which reminds me that I've had a desire for something like
> the old S function  [from the blue book, and library(examples) I think]
>     ichar(ch)
> which would return a vector of integers, each the (decimal) equivalent of
> the (ISO-latin1) representation of the corresponding characters in ch.

> This should be easy enough (and be done in C).  Any volunteers?

That should not be hard to copy from toupper().  For a character vector
it would give a list of integer vectors?

However, I don't think we want ISO-latin-1 hard-wired ...

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