The fact that strsplit() doesn't say anything about 'split' being longer

than 'x' adds to the confusion:

> strsplit(c("xAy", "xxByB", "xCyCCz"), split=c("A", "B", "C", "D"))

[[1]]

[1] "x" "y"

[[2]]

[1] "xx" "y"

[[3]]

[1] "x" "y" "" "z"

A warning (or error) would go a long way in helping the user realize

they're doing something wrong.

No warning either when 'split' is shorter than 'x' but the length of the

latter is not a multiple of the length of the former:

> strsplit(c("xAy", "xxByB", "xCyCCz"), split=c("A", "B"))

[[1]]

[1] "x" "y"

[[2]]

[1] "xx" "y"

[[3]]

[1] "xCyCCz"

Which is also unexpected given that most binary operations do issue a

warning in this case (e.g. 11:13 * 1:2).

H.

On 12/18/19 06:48, Duncan Murdoch wrote:

> On 18/12/2019 9:42 a.m., IAGO GINÉ VÁZQUEZ wrote:

>> Hi all,

>>

>> In the help of strsplit one can read

>>

>> split character vector (or object which can be coerced to such)

>> containing regular

>> expression<

https://urldefense.proofpoint.com/v2/url?u=http-3A__127.0.0.1-3A39783_help_library_base_help_regular-2520expression&d=DwIDaQ&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=8oX1lQmqWY3lK0RSHzCrjkg95jmR7nr4Q0GU3Nw13qA&s=Tfpsttj1v1lIOp9QlfoqGJ1UsKCFOndwgmaNd6XT64s&e=
>> >(s) (unless fixed = TRUE) to use for splitting. If empty matches

>> occur, in particular if split has length 0, x is split into single

>> characters. Ifsplit has length greater than 1, it is re-cycled along x.

>>

>> Taking into account that split is said to be a vector (not a length 1

>> vector) and the last claim above, I would expect that the output of

>>

>>

>> strsplit("3:4", split = c(",",":"), fixed = TRUE)

>>

>> was the same than the output of

>>

>> strsplit("3:4", split = c(":"), fixed = TRUE)

>>

>> that is, splitting by "," (without effect in this example) and also by

>> ":"

>>

>> [[1]]

>> [1] "3" "4"

>>

>> But, instead, I get

>> [[1]]

>> [1] "3:4"

>>

>> Am I wrongly understanding the help? Is it an expected output?

>> I tried with R 3.6.1 for Windows (10).

>

> Yes, you are misunderstanding the help. Your input x has length 1, so

> only the first element of split will be used. If you wanted to use

> both, you would need a longer x. For example,

>

> > strsplit(c("1:2", "3:4"), split=c(",", ":"), fixed=TRUE)

> [[1]]

> [1] "1:2"

>

> [[2]]

> [1] "3" "4"

>

> The first element is split using "," -- since there are none, there's no

> splitting done. The second element is split using ":".

>

> Duncan Murdoch

>

> ______________________________________________

>

[hidden email] mailing list

>

https://urldefense.proofpoint.com/v2/url?u=https-3A__stat.ethz.ch_mailman_listinfo_r-2Ddevel&d=DwIDaQ&c=eRAMFD45gAfqt84VtBcfhQ&r=BK7q3XeAvimeWdGbWY_wJYbW0WYiZvSXAJJKaaPhzWA&m=8oX1lQmqWY3lK0RSHzCrjkg95jmR7nr4Q0GU3Nw13qA&s=9m5muon8TUVCJdnvZtnyuxUQ88pc7qHCUsC6JGDF1qM&e=
>

--

Hervé Pagès

Program in Computational Biology

Division of Public Health Sciences

Fred Hutchinson Cancer Research Center

1100 Fairview Ave. N, M1-B514

P.O. Box 19024

Seattle, WA 98109-1024

E-mail:

[hidden email]
Phone: (206) 667-5791

Fax: (206) 667-1319

______________________________________________

[hidden email] mailing list

https://stat.ethz.ch/mailman/listinfo/r-devel