Repository navigation
Column silently dropped when its name conflicts with value col name in gather.data.frame() #347
Description
gather.data.frame() computes which columns to gather using this snippet.
quos <- quos(...)
if (is_empty(quos)) {
gather_vars <- setdiff(names(data), c(key_var, value_var))
} else {
gather_vars <- unname(tidyselect::vars_select(names(data), !!! quos))
}When the user doesn't provide a ... argument, the gather columns are computed to be anything that's not key or value. This logic works when there's no existing column having the same name as value. If there is, that column would be silently dropped from the gathering.
I've produced a simple reprex below to illustrate.
packageVersion("tidyr")
#> [1] '0.7.0'
library(tidyr)
library(tibble)
XYZ <- data.frame(
X = rnorm(2, 0, 1),
Y = rnorm(2, 0, 2),
Z = rnorm(2, 0, 4)
)
gather(XYZ, name, value)
#> name value
#> 1 X 0.1051179
#> 2 X 1.4617993
#> 3 Y -0.9121167
#> 4 Y 2.5378557
#> 5 Z -2.1496032
#> 6 Z -2.4815070
gather(XYZ, name, Y)
#> Y name Y
#> 1 -0.9121167 X 0.1051179
#> 2 2.5378557 X 1.4617993
#> 3 -0.9121167 Z -2.1496032
#> 4 2.5378557 Z -2.4815070
Activity
hadley commentedon Nov 16, 2017
Slightly more minimal reprex, along with behaviour for tibbles.
Created on 2017-11-16 by the reprex package (0.1.1.9000).
hadley commentedon Nov 16, 2017
Basically same issue as #255 but for
gather(), which uses a slightly different code path.