使用 ggplot2 和 dplyr 进行编程 [英] Programming with ggplot2 and dplyr

问题描述

我想使用管道将 dplyr 和 ggplot 组合在一个函数中，现在正在努力解决一些问题.

这是第一个正在运行的简单方法.函数采用数据框并按指定的列和值进行过滤.

foo <- function(df, y, t = 4){tmp <-df%>%过滤器(!!enquo(y)> t)ggplot(tmp, aes_(substitute(y))) +geom_histogram()}foo(mtcars, cyl)

现在我试图直接通过管道连接到 ggplot 函数...给出一个错误

foo <- function(df, y, t=4){df%＞%过滤器(!!enquo(y)> t)％>％ggplot(aes_(substitute(y))) +geom_histogram()}foo(mtcars, cyl)

<块引用>

FUN(X[[i]], ...) 中的错误:找不到对象 'cyl'另外: 警告信息:在 FUN(X[[i]], ...) 中:重新开始中断的承诺评估

还有最后一个.如何添加构面?

foo <- function(df, y, gr, t=4){df%＞%过滤器(!!enquo(y)> t)％>％ggplot(aes_(substitute(y))) +geom_histogram() +facet_grid(~gr)}foo(mtcars, y= cyl, gr= vs)

编辑

第二个问题可以使用 aes_q 代替 aes_ 解决 &替换. (v0.2.0) 于 2018 年 4 月 4 日创建.

I want to combine dplyr and ggplot within one function using piping and struggling with some issues now.

Here is the first easy one which is working. Function which takes a dataframe and filters by a specified column and value.

foo <- function(df, y, t = 4){
  tmp <- df %>% 
          filter(!!enquo(y) > t)
  ggplot(tmp, aes_(substitute(y))) + 
      geom_histogram()  
}
foo(mtcars, cyl)

Now I'm trying to pipe directly to the ggplot function...gives an error

foo <- function(df, y, t=4){
  df %>% 
     filter(!!enquo(y) > t) %>% 
        ggplot(aes_(substitute(y))) + 
            geom_histogram()  
}
foo(mtcars, cyl)

Error in FUN(X[[i]], ...) : object 'cyl' not found In addition: Warning message: In FUN(X[[i]], ...) : restarting interrupted promise evaluation

and the last one. How to add a facet?

foo <- function(df, y, gr, t=4){
  df %>% 
       filter(!!enquo(y) > t) %>% 
  ggplot(aes_(substitute(y))) + 
      geom_histogram() +  
      facet_grid(~gr)
}
foo(mtcars, y= cyl, gr= vs)

Edit

The second issue can be solved using aes_q instead of aes_ & substitute. Source

foo <- function(df, y, gr, t=4){
  y <- enquo(y)
  df %>% 
    filter(!!y > t) %>% 
       ggplot(aes_q(y)) + 
           geom_histogram()
}
foo(mtcars, cyl)

Using ggplot2_2.2.1

解决方案

ggplot2 v3.0.0 released in July 2018 supports !! (bang bang), !!!, and :=.

facet_wrap() and facet_grid() support vars() inputs. The first two arguments of facet_grid() become rows and cols. facet_grid(vars(cyl), vars(am, vs)) is equivalent to facet_grid(cyl ~ am + vs) and facet_grid(cols = vars(am, vs)) is equivalent to facet_grid(. ~ am + vs).

So your example can be modified as follow:

library(rlang)
library(tidyverse)

foo <- function(df, y, gr, t=4) {
  y <- enquo(y)
  gr <- enquo(gr)

  df %>% 
    filter(!!y > t) %>% 
    ggplot(aes(!!y)) + 
    geom_histogram() +  
    facet_grid(cols = vars(!!gr))
}

foo(mtcars, y= cyl, gr= vs)
#> `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

Created on 2018-04-04 by the reprex package (v0.2.0).

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