为啥 plotly 条形图在 R 中不按顺序使用我指定的颜色，我如何强制它按顺序使用我的颜色？

Posted 2023-02-18

【中文标题】为啥 plotly 条形图在 R 中不按顺序使用我指定的颜色，我如何强制它按顺序使用我的颜色？

【英文标题】：Why does plotly bar chart not use my specified colors in order in R, and how do I force it to use my colors in order?为什么 plotly 条形图在 R 中不按顺序使用我指定的颜色，我如何强制它按顺序使用我的颜色？

【发布时间】：2021-10-13 10:02:23

【问题描述】：

我有一个数据集，我想在 R Shiny 中将其变成一个绘图图表。我也有一长串颜色，但它们需要用于任何类别，但必须按顺序使用（例如，除非前三种颜色已经使用，否则绘图不应使用第 4 种颜色，依此类推）。

出于某种原因，只是为了我的条形图（饼图没有这个问题），阴谋地选择乱序的颜色。例如，这里是数据：

library(dplyr)
test <- tibble(project = c("big", "medium", "big", "medium"),
               capacity = c(10, 5, 16, 3),
               date = c("Aug 2021", "Aug 2021", "Sep 2021", "Sep 2021"),
               date_num = as.Date("2021-08-01", "2021-08-01", "2021-09-01", "2021-09-01")) %>%
  dplyr::mutate(date = reorder(date, date_num))

这是我拥有所有颜色时的情节：

all_colors <- c("#CA001B", "#1D28B0", "#D71DA4", "#00A3AD", "#FF8200", "#753BBD", "#00B5E2", "#008578", "#EB6FBD", "#FE5000", "#6CC24A", "#D9D9D6", "#AD0C27", "#950078")

library(plotly)
fig <- plot_ly(test, x = ~date, y = ~capacity, type = 'bar', name = ~project, color = ~project, colors = all_colors) %>%
  layout(legend = list(orientation = 'h', x = .5, xanchor = "center", y = -.3), font = line_chart_text_format, barmode = "stack")


fig

但是当我只包含前两种颜色时，它看起来是正确的：

some_colors <- c("#CA001B", "#1D28B0")

library(plotly)
fig <- plot_ly(test, x = ~date, y = ~capacity, type = 'bar', name = ~project, color = ~project, colors = some_colors) %>%
  layout(legend = list(orientation = 'h', x = .5, xanchor = "center", y = -.3), font = line_chart_text_format, barmode = "stack")


fig

如何强制 plotly 按顺序使用我的颜色？我不想将颜色映射到特定变量，因为未来的可视化可能会有更多类别。出于同样的原因，我不想只包含最小数量的可行颜色。

【参考方案1】：

不确定内部结构。看起来像情节从最后一个开始挑选颜色。一种解决方法是使用colors = ~all_colors[seq_along(unique(project))]):

library(dplyr)
library(plotly)

test <- tibble(project = c("big", "medium", "big", "medium"),
               capacity = c(10, 5, 16, 3),
               date = c("Aug 2021", "Aug 2021", "Sep 2021", "Sep 2021"),
               date_num = as.Date("2021-08-01", "2021-08-01", "2021-09-01", "2021-09-01")) %>%
  dplyr::mutate(date = reorder(date, date_num))

all_colors <- c("#CA001B", "#1D28B0", "#D71DA4", "#00A3AD", "#FF8200", "#753BBD", "#00B5E2", "#008578", "#EB6FBD", "#FE5000", "#6CC24A", "#D9D9D6", "#AD0C27", "#950078")


plot_ly(test, x = ~date, y = ~capacity, type = 'bar', name = ~project, 
        color = ~project, colors = ~all_colors[seq_along(unique(project))]) %>%
  layout(legend = list(orientation = 'h', x = .5, xanchor = "center", y = -.3), barmode = "stack")

test <- tibble(project = c("big", "low", "medium", "superbig"),
               capacity = c(10, 5, 16, 3),
               date = c("Aug 2021", "Aug 2021", "Sep 2021", "Sep 2021"),
               date_num = as.Date("2021-08-01", "2021-08-01", "2021-09-01", "2021-09-01")) %>%
  dplyr::mutate(date = reorder(date, date_num))

plot_ly(test, x = ~date, y = ~capacity, type = 'bar', name = ~project, 
        color = ~project, colors = ~all_colors[seq_along(unique(project))]) %>%
  layout(legend = list(orientation = 'h', x = .5, xanchor = "center", y = -.3), barmode = "stack")