[R] Character (1a, 1b) to numeric

[David Winsemius]

It might be easier to simply assign names to the numeric vector if you 
already have numeric and character vectors of the right lengths. Using 
Heibergers's vectors:


xc <-  c("1", "1a", "1b", "1c", "2", "2a", "2b", "2c")
xn <- c(1, 1.3, 1.5, 1.7, 2, 2.3, 2.5, 2.7)

names(xn) <- xc

testdata <- rep(c("1", "1a", "1b", "1c",
                     "2", "2a", "2b", "2c",
                    "3", "3a", "3b", "3c"), times=c(1:6,6:1))

xn[ testdata ]  #  NA's when there's no match is a feature.

-- 
David.

On 7/10/20 7:08 PM, Richard O'Keefe wrote:
> This can be done very simply because vectors in R can have
> named elements, and can be indexed by strings.
>
>> stage <- c("1" = 1, "1a" = 1.3, "1b" = 1.5, "1c" = 1.7,
> +            "2" = 2, "2a" = 2.3, "2b" = 2.5, "2c" = 2.7,
> +            "3" = 3, "3a" = 3.3, "3b" = 3.5, "3c" = 3.7)
>
>> testdata <- rep(c("1", "1a", "1b", "1c",
> +                   "2", "2a", "2b", "2c",
> +                   "3", "3a", "3b", "3c"), times=c(1:6,6:1))
>
>> stage[testdata]
>    1  1a  1a  1b  1b  1b  1c  1c  1c  1c   2   2   2   2   2  2a  2a  2a  2a
>   2a
> 1.0 1.3 1.3 1.5 1.5 1.5 1.7 1.7 1.7 1.7 2.0 2.0 2.0 2.0 2.0 2.3 2.3 2.3 2.3
> 2.3
>   2a  2b  2b  2b  2b  2b  2b  2c  2c  2c  2c  2c   3   3   3   3  3a  3a  3a
>   3b
> 2.3 2.5 2.5 2.5 2.5 2.5 2.5 2.7 2.7 2.7 2.7 2.7 3.0 3.0 3.0 3.0 3.3 3.3 3.3
> 3.5
>   3b  3c
> 3.5 3.7
>
> On Sat, 11 Jul 2020 at 05:51, Jean-Louis Abitbol <abitbol using sent.com> wrote:
>
>> Dear All
>>
>> I have a character vector,  representing histology stages, such as for
>> example:
>> xc <-  c("1", "1a", "1b", "1c", "2", "2a", "2b", "2c")
>>
>> and this goes on to 3, 3a etc in various order for each patient. I do have
>> of course a pre-established  classification available which does change
>> according to the histology criteria under assessment.
>>
>> I would want to convert xc, for plotting reasons, to a numeric vector such
>> as
>>
>> xn <- c(1, 1.3, 1.5, 1.7, 2, 2.3, 2.5, 2.7)
>>
>> Unfortunately I have no clue on how to do that.
>>
>> Thanks for any help and apologies if I am missing the obvious way to do it.
>>
>> JL
>> --
>> Verif30042020
>>
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>
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> and provide commented, minimal, self-contained, reproducible code.