How to control ordering of stacked bar chart using identity on ggplot2

Question

Using this dummy data.frame

ts <- data.frame(x=1:3, y=c("blue", "white", "white"), z=c("one", "one", "two"))

I try and plot with category "blue" on top.

ggplot(ts, aes(z, x, fill=factor(y, levels=c("blue","white" )))) + geom_bar(stat = "identity")

gives me "white" on top. and

ggplot(ts, aes(z, x, fill=factor(y, levels=c("white", "blue")))) + geom_bar(stat = "identity")

reverses the colors, but still gives me "white" on top. How can I get "blue" on top?

score 74 · Answer 1 · edited Oct 20 '17 at 15:54

74

For what it is worth, in ggplot2 version 2.2.1 the order of the stack is no longer determined by the row order in the data.frame. Instead, it matches the order of the legend as determined by the order of levels in the factor.

d <- data.frame(
  y=c(0.1, 0.2, 0.7),
  cat = factor(c('No', 'Yes', 'NA'), levels = c('NA', 'Yes', 'No')))

# Original order
p1 <- ggplot(d, aes(x=1, y=y, fill=cat)) +
  geom_bar(stat='identity')

# Change order of rows
p2 <- ggplot(d[c(2, 3, 1), ], aes(x=1, y=y, fill=cat)) +
  geom_bar(stat='identity')

# Change order of levels
d$cat2 <- relevel(d$cat, 'Yes')
p3 <- ggplot(d, aes(x=1, y=y, fill=cat2)) +
  geom_bar(stat='identity') 

grid.arrange(p1, p2, p3, ncol=3)

It results in the below plot:

edited Oct 20 '17 at 15:54

Prradep

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answered May 10 '17 at 15:16

Inhabitant

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Thank you for telling us it is due to the new ggplot2 version. Somehow my plots were suddenly all wrong and I spent a lot of time locating the mistake with myself. Only now I know the problem is with 'ggplot2' instead and I can safely change the order manually – Vincent Nov 16 '17 at 12:03
1

Oh my gosh, I spent like an hour trying to figure out why the behavior of my code had changed... – Ecksters May 04 '18 at 09:57
1

I was struggling with the ordering of `NA` values and it needs to be added as a proper level. An easy way to do just that is the convenience function `addNA()`. – hannes101 Aug 31 '18 at 12:06
Ecksters, watch your words – WJH Feb 15 '22 at 21:03

score 70 · Accepted Answer · edited Jun 20 '20 at 09:12

70

I've struggled with the same issue before. It appears that ggplot stacks the bars based on their appearance in the dataframe. So the solution to your problem is to sort your data by the fill factor in the reverse order you want it to appear in the legend: bottom item on top of the dataframe, and top item on bottom:

ggplot(ts[order(ts$y, decreasing = T),],
       aes(z, x, fill=factor(y, levels=c("blue","white" )))) + 
  geom_bar(stat = "identity")

Edit: More illustration

Using sample data, I created three plots with different orderings of the dataframe, I thought that more fill-variables would make things a bit clearer.

set.seed(123)
library(gridExtra)
df <- data.frame(x=rep(c(1,2),each=5),
                 fill_var=rep(LETTERS[1:5], 2),
                 y=1)
#original order   
p1 <- ggplot(df, aes(x=x,y=y,fill=fill_var))+
  geom_bar(stat="identity") + labs(title="Original dataframe")


#random order
p2 <- ggplot(df[sample(1:10),],aes(x=x,y=y,fill=fill_var))+
  geom_bar(stat="identity") + labs(title="Random order")
#legend checks out, sequence wird

#reverse order
p3 <- ggplot(df[order(df$fill_var,decreasing=T),],
             aes(x=x,y=y,fill=fill_var))+
  geom_bar(stat="identity") + labs(title="Reverse sort by fill")

plots <- list(p1,p2,p3)

do.call(grid.arrange,plots)

edited Jun 20 '20 at 09:12

Community

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answered Sep 02 '15 at 07:10

Heroka

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Thank you for the thorough example! I thought the order was determined alphabetically, so this is very helpful. – Tom Sep 02 '15 at 08:22
1

You're welcome! If any of the provided solutions work to your satisfaction, can you accept one? Keeps others from answering the question. – Heroka Sep 02 '15 at 09:09
1

Nice answer! Perhaps others will find this SO question useful: http://stackoverflow.com/questions/30739602/ggplot-reorder-stacked-bar-plot-based-on-values-in-data-frame – lawyeR Sep 02 '15 at 10:09
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Unfortunately this doesn't seem to work with dplyr's `arrange()` function. Switching the order of the stack category has no effect. – jzadra Mar 30 '17 at 21:24
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All of the plots in your example have the same order for me (R 3.4.3) – Parsa Feb 28 '18 at 18:26
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It's quite an old answer. Maybe have a look at Inhabitant's solution below. – Heroka Mar 04 '18 at 13:37

score 13 · Answer 3 · edited May 19 '17 at 17:52

13

Use the group aethetic in the ggplot() call. This ensures that all layers are stacked in the same way.

series <- data.frame(
  time = c(rep(1, 4),rep(2, 4), rep(3, 4), rep(4, 4)),
  type = rep(c('a', 'b', 'c', 'd'), 4),
  value = rpois(16, 10)
)

ggplot(series, aes(time, value, group = type)) +
  geom_col(aes(fill = type)) +
  geom_text(aes(label = type), position = "stack")

edited May 19 '17 at 17:52

Paul Roub

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answered May 19 '17 at 17:32

Anne

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thanks! I had this issue that the stacking didn't work, and your solution nailed it – amann Jul 02 '20 at 12:30

score 13 · Answer 4 · answered Sep 20 '19 at 13:33

Messing with your data in order to make a graph look nice seems like a bad idea. Here's an alternative that works for me when using position_fill():

ggplot(data, aes(x, fill = fill)) + geom_bar(position = position_fill(reverse = TRUE))

The reverse = TRUE argument flips the order of the stacked bars. This works in position_stack also.

score 6 · Answer 5 · edited Sep 03 '17 at 21:25

6

I have the exactly same problem today. You can get blue on top by using order=-as.numeric():

ggplot(ts, 
aes(z, x, fill=factor(y, levels=c("blue","white")), order=-as.numeric(y))) + 
geom_bar(stat = "identity")

edited Sep 03 '17 at 21:25

zakrapovic

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answered Sep 02 '15 at 07:24

Fukushi

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Kevin Wang · Answer 6 · 2018-08-05T03:31:58.210

I had a similar issue and got around by changing the level of the factor. thought I'd share the code:

library(reshape2)
library(ggplot2)

group <- c(
  "1",
  "2-4",
  "5-9",
  "10-14",
  "15-19",
  "20-24",
  "25-29",
  "30-34",
  "35-39",
  "40-44",
  "45-49"
)

xx <- factor(group, levels(factor(group))[c(1, 4, 11, 2, 3, 5:10)])

method.1 <- c(36, 14, 8, 8, 18, 1, 46, 30, 62, 34, 34)
method.2 <- c(21, 37, 45, 42, 68, 41, 16, 81, 51, 62, 14)
method.3 <- c(37, 46, 18, 9, 16, 79, 46, 45, 70, 42, 28)  
elisa.neg <- c(12, 17, 18, 6, 19, 14, 13, 13, 7, 4, 1)  
elisa.eq <- c(3, 6, 3, 14, 1, 4, 11, 13, 5, 3, 2)

test  <- data.frame(person = xx, 
                    "Mixture Model" = method.1,
                    "Censoring" = method.3,
                    "ELISA neg" = elisa.neg,
                    "ELISA eqiv" = elisa.eq) 

melted <- melt(test, "person")
melted$cat <- ifelse(melted$variable == "Mixture.Model", "1",
                     ifelse(melted$variable == "Censoring", "2", "3"))

melted$variable = factor(melted$variable, levels = levels(melted$variable)[c(1, 2, 4,3 )]) ## This did the trick of changing the order

ggplot(melted, aes(x = cat, y = value, fill = variable)) + 
  geom_bar(stat = 'identity') + facet_wrap(~ person) +
  theme(axis.ticks.x=element_blank(),
        axis.text.x=element_blank()) + 
  labs(title = "My Title",
       y = "Per cent", x = "Age Group", fill = "")

(Sorry, this is my data, I didn't reproduce using the data from the original post, hope it's ok!)

How to control ordering of stacked bar chart using identity on ggplot2

6 Answers6

Edit: More illustration

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