如何在 R 中使用颜色十六进制值作为函数参数？

Posted 2023-04-13

【中文标题】如何在 R 中使用颜色十六进制值作为函数参数？

【英文标题】：How to use color hex values as a function argument in R?

【发布时间】：2020-10-14 12:27:34

【问题描述】：

我正在使用用户定义的函数创建一个绘图并将颜色作为选项传递。将as_label 或quo_name 与colors by name（例如grey 或pink）一起使用可以正常工作。

但是当我传递 hex 代码 时，它 失败，即使我只传递没有 # 的 alpha 数值，它仍然不会将其作为字符串。

小例子：

udf_tax_rev_plot <- function(background_line_color = grey)
  
  background_line_color = enquo(background_line_color)
  
  print(as_label(background_line_color) )


udf_tax_rev_plot(33ffff) 

##### output ##### 
Error: unexpected symbol in "udf_tax_rev_plot(33ffff"

实际剧情代码：

udf_tax_rev_plot <- function(background_line_color = grey)
  
  background_line_color = enquo(background_line_color)

  tax_rev %>% 
    mutate(highlight_type = case_when(country %in%
                                   c("India","Singapore","Malaysia","Norway",
                                     "Denmark","United States","United Kingdom","China") ~ "Yes",
                                 TRUE ~ "No")) %>%
  ggplot() +
    geom_line(aes(x = year, y = round(tax_revnue_perc_of_gdp,2), col = country), size = 1.1) +
    scale_x_continuous(breaks = seq(from = 1980, to = 2020, by = 5)) +
    scale_y_continuous(labels = label_dollar(prefix = "", suffix = " %"),
                       breaks = seq(from = 0, to = 60, by = 5)) +
    gghighlight(highlight_type == "Yes",
                unhighlighted_params = list(size = 1, colour = alpha(as_label(background_line_color), 0.4))) +
    facet_wrap(~continent) +
    theme_viny_bright() +
    theme(axis.text.x = element_text(angle = 90)
            ) +
    labs(title = "Total Tax Revenue earned % of GDP for world countries across time",
         subtitle = "created by ViSa",
         caption = "Data Source: Gapminder",
         y = "Total Tax Revenue % of GDP" 
         )


udf_tax_rev_plot(#33ffff)

我该如何解决这个问题？

更新

这是带有要重现的gapminder数据的代码

library(tidyverse)
library(scales)
library(gghighlight)
library(gapminder)

udf_tax_rev_plot <- function(background_line_color = grey)
  
  background_line_color = enquo(background_line_color)

  gapminder %>% 
    mutate(highlight_type = case_when(country %in%
                                   c("India","Singapore","Malaysia","Norway",
                                     "Denmark","United States","United Kingdom","China") ~ "Yes",
                                 TRUE ~ "No")) %>%
  ggplot() +
    geom_line(aes(x = year, y = round(gdpPercap,2), col = country), size = 1.1) +
    #scale_x_continuous(breaks = seq(from = 1980, to = 2020, by = 5)) +
    #scale_y_continuous(labels = label_dollar(prefix = "", suffix = " %"),
                       #breaks = seq(from = 0, to = 60, by = 5)) +
    gghighlight(highlight_type == "Yes",
                unhighlighted_params = list(size = 1, colour = alpha(as_label(background_line_color), 0.4))) +
    facet_wrap(~continent) +
    theme_minimal() +
    theme(axis.text.x = element_text(angle = 90)
            ) +
    labs(title = "Total Tax Revenue earned % of GDP for world countries across time",
         subtitle = "created by ViSa",
         caption = "Data Source: Gapminder",
         y = "Total Tax Revenue % of GDP" 
         )


udf_tax_rev_plot(pink)

【问题讨论】：

如果不带引号的变量以 # 或数字开头，则不能传递它们。用户必须使用双引号或单引号

@AllanCameron 哦 ...我尝试使用相同的代码在引号 udf_tax_rev_plot("#33ffff") 中传递十六进制，但它给出了错误。我想我必须修改它来处理"hex color" 和color_name。但这很奇怪。

是的，长话短说，这里没有理由使用enquo()。只需将颜色作为字符传递并在函数中使用它。

是的@Adam，我同意，但我正在考虑传递颜色名称，因为它不带引号和带或不带引号的十六进制，但我想这不是一个简单的选择，所以会保持简单你提到的方式！

【参考方案1】：

这适用于您提供的数据：

library(tidyverse)
library(scales)
library(gghighlight)
library(gapminder)

udf_tax_rev_plot <- function(background_line_color = "grey")
  
  
  gapminder %>% 
    mutate(highlight_type = case_when(country %in%
                                        c("India","Singapore","Malaysia","Norway",
                                          "Denmark","United States","United Kingdom","China") ~ "Yes",
                                      TRUE ~ "No")) %>%
    ggplot() +
    geom_line(aes(x = year, y = round(gdpPercap,2), col = country), size = 1.1) +
    scale_x_continuous(breaks = seq(from = 1980, to = 2020, by = 5)) +
    scale_y_continuous(labels = label_dollar(prefix = "", suffix = " %"),
                       breaks = seq(from = 0, to = 60, by = 5)) +
    gghighlight(highlight_type == "Yes",
                unhighlighted_params = list(size = 1, colour = alpha(background_line_color, 0.4))) +
    facet_wrap(~continent) +
    theme_minimal() +
    theme(axis.text.x = element_text(angle = 90)
    ) +
    labs(title = "Total Tax Revenue earned % of GDP for world countries across time",
         subtitle = "created by ViSa",
         caption = "Data Source: Gapminder",
         y = "Total Tax Revenue % of GDP" 
    )


udf_tax_rev_plot("pink")

您必须以字符串的形式提供颜色。

所以要么像这样：udf_tax_rev_plot("#33ffff") 或像这样：udf_tax_rev_plot('#33ffff')

【讨论】：

udf_tax_rev_plot("#33ffff") 给出错误：Error: Unknown colour name: "#33ffff"。我将尝试将上面的代码与 gapminder 数据一起放置，以便可以复制它

你能分享一个示例数据框吗？这样会更容易找到问题

我更新了我的答案。它似乎工作。确保不要使用enquo，也不要使用as_label。

我已经用 gapminder 数据更新了原始帖子，但我会尝试用你更新的代码来实现。非常感谢！！！