我有一个具有以下结构的数据集:
Classes ‘tbl_df’ and 'data.frame': 10 obs. of 7 variables:
$ GdeName : chr "Aeugst am Albis" "Aeugst am Albis" "Aeugst am Albis" "Aeugst am Albis" ...
$ Partei : chr "BDP" "CSP" "CVP" "EDU" ...
$ Stand1971: num NA NA 4.91 NA 3.21 ...
$ Stand1975: num NA NA 5.389 0.438 4.536 ...
$ Stand1979: num NA NA 6.2774 0.0195 3.4355 ...
$ Stand1983: num NA NA 4.66 1.41 3.76 ...
$ Stand1987: num NA NA 3.48 1.65 5.75 ...
我想提供一个允许计算任何值之间的差异的函数,并且我想使用dplyr
s mutate
函数如下:(假设参数from
and to
作为参数传递)
from <- "Stand1971"
to <- "Stand1987"
data %>%
mutate(diff = from - to)
当然,这是行不通的,因为dplyr
使用非标准评估。我知道现在有一个优雅的解决方案可以使用mutate_
,我读过这个小插图 http://cran.r-project.org/web/packages/dplyr/vignettes/nse.html,但我仍然无法理解它。
该怎么办?
这是数据集的前几行,用于重现示例
structure(list(GdeName = c("Aeugst am Albis", "Aeugst am Albis",
"Aeugst am Albis", "Aeugst am Albis", "Aeugst am Albis", "Aeugst am Albis",
"Aeugst am Albis", "Aeugst am Albis", "Aeugst am Albis", "Aeugst am Albis"
), Partei = c("BDP", "CSP", "CVP", "EDU", "EVP", "FDP", "FGA",
"FPS", "GLP", "GPS"), Stand1971 = c(NA, NA, 4.907306434, NA,
3.2109535926, 18.272143463, NA, NA, NA, NA), Stand1975 = c(NA,
NA, 5.389079711, 0.4382328556, 4.5363022622, 18.749259742, NA,
NA, NA, NA), Stand1979 = c(NA, NA, 6.2773722628, 0.0194647202,
3.4355231144, 25.294403893, NA, NA, NA, 2.7055961071), Stand1983 = c(NA,
NA, 4.6609804428, 1.412940467, 3.7563539244, 26.277246489, 0.8529335746,
NA, NA, 2.601878177), Stand1987 = c(NA, NA, 3.4767860929, 1.6535933856,
5.7451770193, 22.146844746, NA, 3.7453183521, NA, 13.702211858
)), .Names = c("GdeName", "Partei", "Stand1971", "Stand1975",
"Stand1979", "Stand1983", "Stand1987"), class = c("tbl_df", "data.frame"
), row.names = c(NA, -10L))