使用mutate和dplyr创建一个带有替换值的列 [英] creating a column with replaced values using mutate and dplyr

问题描述

这可能是stackoverflow上的一个重复，并且是 dplyr mutate替换动态的后续问题变量名称。

This likely a duplicate somewhere on stackoverflow and is a followup question to dplyr mutate replace dynamic variable name.

现在我试图使用变量名作为新列。

Now I am trying to use a variable name as the new column.

某些东西：

 library(ggplot2)
 data(mpg)
 mpg %>% mutate(hwy=replace(hwy, hwy>29,10))

以下代码创建一个新列称为varname，但是我想用hwy替换列。

The code below creates a new column called varname but I want to replace the column with hwy.

varname = "hwy"
mpg %>% mutate_(varname=interp(~replace(varname, varname>29, 10), varname=as.name(varname)))

如下所示：

mpg %>% mutate_(as.name(varname)=interp(~replace(varname, varname>29, 10), varname=as.name(varname)))

但这不行。我认为点符号是在玩，但不太确定如何包围我的头围。

but this doesn't work. I think the dots notation is in play but not quite sure how to wrap my head around it.

谢谢。

推荐答案

而不是替换 mpg 现有的 hwy 变量以下说明相同的事情，并将其放入上下文中：

Rather than replace mpg's existing hwy variable I did the following to illustrate the same thing and put it into context:

从您以前的问题：

library(dplyr)
library(ggplot2)
library(lazyeval)

data(mpg)

# "normal" dplyr
a <- mpg %>% mutate(hwybin=replace(hwy>25,1,0))


# varying just the RHS
varname <- "hwy"
b <- mpg %>% mutate_(hwybin=interp(~replace(varname>25, 1 ,0),
                                   varname=as.name(varname)))

identical(a, b)

对于此特定r问题：

# varying both RHS and LHS

colname <- "hwybin"
z <- mpg %>% mutate_(.dots=setNames(list(interp(~replace(varname>25, 1 ,0),
                            varname=as.name(varname))), colname))

# tests
identical(a, z)
identical(b, z)

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