概要概要

でheight指定された値ごとにbarplot()、対応する色を作成します。この場合、灰色から濃い青色に変化するカラーパレットを作成します。

再現可能な例

カラーピッカーは、一般的な色を16進色の値に変換するのに役立ちます。

# create data frame
df <- data.frame(
  id = 1:5
  , Coolness_Level = 1:5
  , Coolness_Color = NA
  , stringsAsFactors = FALSE
)

# view data
df
# id Coolness_Level Coolness_Color
# 1  1              1             NA
# 2  2              2             NA
# 3  3              3             NA
# 4  4              4             NA
# 5  5              5             NA


# I want colors to progress
# from gray to dark blue
color.function <- colorRampPalette( c( "#CCCCCC" , "#104E8B" ) )

# decide how many groups I want, in this case 5
# so the end product will have 5 bars
color.ramp <- color.function( n = nrow( x = df ) )

# view colors
color.ramp
# [1] "#CCCCCC" "#9DACBB" "#6E8DAB" "#3F6D9B" "#104E8B"

# assign every row in df
# a color
# based on their $Coolness_Level
df$Coolness_Color <-
  as.character(
    x = cut(
      x = rank( x = df$Coolness_Level )  # used to assign order in the event of ties
      , breaks = nrow( x = df )  # same as the 'n' supplied in color.function()
      , labels = color.ramp  # label the groups with the color in color.ramp
    )
  )

# view the data
df
# id Coolness_Level Coolness_Color
# 1  1              1        #CCCCCC
# 2  2              2        #9DACBB
# 3  3              3        #6E8DAB
# 4  4              4        #3F6D9B
# 5  5              5        #104E8B

# make barplot
# and save as PNG
png( filename = "my_cool_barplot.png"
     , units = "px"
     , height = 1600
     , width = 1600
     , res = 300
     )
barplot( height = df$Coolness_Level
         , names.arg = df$id
         , las = 1
         , col = df$Coolness_Color
         , border = NA  # eliminates borders around the bars
         , main = "Is Coolness Correlated with Higher ID #s?"
         , ylab = "Coolness Level"
         , xlab = "ID #"
         )
# shut down plotting device
dev.off()

# end of script #