CODEWITHSUNDEEP
r
nouse
nouse

Reputation: 3471

Barplot ignores colorpalette

I calculated means from different columns in different dataframes and put those into another dataframe to plot them. From this code

 res <- structure(list(`2012` = 6.86537485268066, 
                       `2013` = 5.91282899425944, 
    `2014` = 4.45070377934188),
     .Names = c("2012", "2013", "2014"),    
     row.names = c(NA, -1L), class = "data.frame")
colors<- c("yellow", "red", "green")
ticks <- c(0,8)
barplot(as.matrix(res), ylim=ticks, ylab="Mean Ratio", 
        width=0.5, col=colors, xlab="Year", main="Mean ratio per year")

i get a uni-coloured barplot in yellow.

Same is true for

myMat<-matrix(runif(3), ncol=3) 
barplot(myMat, col=colors)

Why is this? I managed to do the graph with ggplot and reshape, but it still bothers me.

Upvotes: 4

Views: 64

Answers (2)

RHA
RHA

Reputation: 3862

Barplot assumes that you use stacked bars, and you have only one category. If you specify beside=TRUE, that is no longer the case:

barplot(as.matrix(res), ylim=ticks, ylab="Mean Ratio", beside=TRUE,
        width=0.5, col=colors, xlab="Year", main="Mean ratio per year" )

Upvotes: 3

Ben Bolker
Ben Bolker

Reputation: 226577

When you hand barplot() something that looks like a matrix (i.e. it has dimensions, or more specifically a dim attribute), it colors each segment according to cols. What it is doing in your case is assuming that each of the values is the first segment in its category. To convert this simple data frame to a vector, try unlist() ...

barplot(unlist(res), ylim=ticks, ylab="Mean Ratio", 
        width=0.5, col=colors, xlab="Year",
        main="Mean ratio per year")

Upvotes: 4

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