将变量名称粘贴到mutate(dplyr)中 [英] Paste variable name in mutate (dplyr)
问题描述
我尝试在mutate_()函数(dplyr)中使用paste()创建一个变量。
I try to create a variable with paste() in a mutate_() function (dplyr).
我尝试使用此答案修改代码( dplyr-mutate:使用动态变量名),但它不起作用...
I try to adapt code with this answer (dplyr - mutate: use dynamic variable names) but it doesn't work ...
注意:nameVarPeriod1是函数的参数。
nameVarPeriod1=A2
df <- df %>%
group_by(segment) %>%
mutate_((.dots=setNames(mean(paste0("Sum",nameVarPeriod1)), paste0("MeanSum",nameVarPeriod1))))
这将返回一个警告:
Warning message:
In mean.default(paste0("Sum", nameVarPeriod1)) :
argument is not numeric or logical: returning NA
如何将paste0中的字符串作为变量名求值?
How to evaluate the string in paste0 as variable name ?
当我用它替换paste0时,它可以正常工作:
When I replace the paste0 by this it works fine :
df <- df %>%
group_by(segment) %>%
mutate(mean=mean(SumA2))
数据:
structure(list(segment = structure(c(5L, 1L, 4L, 2L, 2L, 14L,
11L, 6L, 14L, 1L), .Label = c("Seg1", "Seg2", "Seg3", "Seg4",
"Seg5", "Seg6", "Seg7", "Seg8", "Seg9", "Seg10", "Seg11", "Seg12",
"Seg13", "Seg14"), class = "factor"), SumA2 = c(107584.9, 127343.87,
205809.54, 138453.4, 24603.46, 44444.39, 103672, 88695.8, 64400,
36815.82)), .Names = c("segment", "SumA2"), row.names = c(NA,
-10L), class = c("tbl_df", "tbl", "data.frame"))
推荐答案
dplyr 0.7.0
起不需要使用 mutate _
。这是一个使用:=
来动态分配变量名和辅助函数
dplyr 0.7.0
onwards does not require use of mutate_
. Here is a solution using :=
to dynamically assign variable names and helper functions quo name
.
阅读 vignette( programming, dplyr)
会有所帮助。另请参见在dplyr的较旧版本中,在`dplyr` 中使用动态变量名称。
It will be helpful to read vignette("programming", "dplyr")
for more info. See also Use dynamic variable names in `dplyr` for older versions of dplyr.
df <- df %>%
group_by(segment) %>%
mutate( !!paste0('MeanSum',quo_name(nameVarPeriod1)) :=
mean(!!as.name(paste0('Sum',quo_name(nameVarPeriod1)))))
dplyr 1.0.0替代:
使用新的 dplyr 1.0.0
中的> cross 函数(当前仅适用于github remotes :: install_github('tidyverse / dplyr'))
我们可以使用 glue
样式语法设置名称,并且可以在名称中包括函数名称和原始列:
dplyr 1.0.0 alternative:
Using the new across
function in dplyr 1.0.0
(currently only on github remotes::install_github('tidyverse/dplyr')
we can set names using glue
style syntax and can include the function name and original column as part of the name:
my_fn <- function(nameVarPeriod1 = 'A2'){
col_list <- paste0('Sum',nameVarPeriod1)
df %>%
group_by(segment) %>%
mutate(across(col_list, list(mean=mean), .names = "{fn}{col}"))
}
my_fn()
# segment SumA2 meanSumA2
# <fct> <dbl> <dbl>
# 1 Seg5 107585. 107585.
# 2 Seg1 127344. 82080.
# 3 Seg4 205810. 205810.
# 4 Seg2 138453. 81528.
# 5 Seg2 24603. 81528.
# 6 Seg14 44444. 54422.
# 7 Seg11 103672 103672
# 8 Seg6 88696. 88696.
# 9 Seg14 64400 54422.
#10 Seg1 36816. 82080.
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