着色方案饼图，ggplot2

Question

我正在使用ggplot2创建一个饼图，但我无法获得正确的饼图颜色。

df <- data.frame(group = c("Information technology", "Laboratory", "Tools", 
                           "Unspecified", "Other"), 
                 value = c(2500, 2000, 1500, 1000, 4000))

# Coloring scheme
blue1 <- "#0a3250"   # darkest blue
blue2 <- "#13517b"
blue3 <- "#2f659f"
blue4 <- "#518ecb"
blue5 <- "#aac8df"
blue6 <- "#d6e7f2"   # lightest blue
colorscheme <- scale_fill_manual(values = c(blue1, blue2, blue3,
                                            blue4, blue5, blue6))
# Data labels: 
df   <- df[!is.na(df$value),]   # Only keeps non-zero segments
lbls <- df$value/sum(df$value)
lbls <- percent(lbls)           # Converts to string and adds % sign
lbls[lbls == "0.0%"] <- ""      # Removes 0.0% as a label

# we now actually plot the data:
ggplot(df, aes(x = "", y = value, fill = group)) +   
    colorscheme +
    geom_bar(width = 1, stat = "identity", col = "white") + 
    xlab("") + ylab("") + 
    theme_bw() + 
    geom_text(aes(x     = 1.90, 
                  y     = value/2 + c(0, cumsum(value)[-length(value)]), 
                  label = lbls), size = 4) + 
    coord_polar(theta = "y") + 
    theme(
      axis.text       = element_blank(), 
      panel.grid      = element_blank(),
      panel.border    = element_blank(),
      legend.key      = element_rect(fill=NULL, colour = "white"),
      legend.key.size = unit(0.5, "cm"),
      legend.title    = element_blank(),
      legend.text     = element_text(size = 9)
)

我想要的是什么：

我希望df中的第一个条目具有颜色blue1，第二个条目blue2等。这样，切片按顺时针顺序从最暗的蓝色变为最浅的蓝色。 此外，图例应按照与df中相同的顺序显示组。

问题是什么：

但是，颜色不是根据df中的位置分配的，而是根据字母顺序分配的。现在，不同色调的蓝色散布在饼图和图例上。

Answer 1

使用分类变量的因子：

df <- data.frame(group=factor(x=1:5, 
         labels=c("Information technology", "Laboratory", "Tools", "Unspecified", "Other")), 
                 value = c(2500, 2000, 1500, 1000, 4000))