默认颜色hue_pal
library(scales)
show_col(hue_pal()(1)) #n为1~6 
show_col(hue_pal()(2)) #n为1~6 Green Sequential “#EDF8E9” “#C7E9C0” “#A1D99B” “#74C476” “#41AB5D” “#238B45” “#005A32” BrBG(divergent) “#8C510A” “#D8B365” “#F6E8C3” “#F5F5F5” “#C7EAE5” “#5AB4AC” “#01665E”
“#7FC97F” “#BEAED4” “#FDC086” “#FFFF99” “#386CB0” “#F0027F” “#BF5B17” ColorBlindFriendly