[External Email] Re: how to rename variables by lopping off first 3 characters

Thanks! This has gotten me on the right track.  One of my mistakes was that
I was explicitly using the word select, as in

rename_at(select(starts_with ....
or
rename_at(select(vars(starts_with ....

--Chris Ryan

On Mon, Mar 14, 2022 at 1:11 PM Bert Gunter <bgunter.4567 at gmail.com> wrote:

If you care to entertain this, one of many simple base R ways to do this
is:

dat <- data.frame(
+    i..One = 1:3,
+    i..Two = letters[1:3],
+    ixx = 5:7)

dat

  i..One i..Two ixx
1      1      a   5
2      2      b   6
3      3      c   7

nm <- names(dat)
nm <- ifelse(substring(nm, 1,3) == "i..",

+              substring(nm,4),
+              nm)

names(dat) <- nm
dat

  One Two ixx
1   1   a   5
2   2   b   6
3   3   c   7

Bert Gunter

"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )


On Mon, Mar 14, 2022 at 9:27 AM Christopher W Ryan via R-help
<r-help at r-project.org> wrote:

I have data coming to me from another source, in which some of the

variable

names begin with "i.."

As in "i..actual_meaningful_var_name"

I would like to remove the first three characters from any variable name

if

they are "i.."

I'm using R on Win 10 and dplyr, so ideally I'm looking for a dplyr
solution. Apparently I'm just not understanding how the various select,
contains, rename_at, rename_with, and so-on dplyr expressions work. I've
tried various arrangements of them, usually resulting in

Error: `contains()` must be used within a *selecting* function.
i See <https://tidyselect.r-lib.org/reference/faq-selection-context.html


A simple select(contains(foo)) I can do fine, to select a subset of
variables. It's combining it with renaming that I am struggling with.

Grateful for any advice.

Thanks.

--Chris Ryan

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