CODEWITHSUNDEEP
rggplot2
user10310704
user10310704

Reputation: 113

ggplot bar charts are always grey

I'm trying to make some stacked bar charts using ggplot2 in R, but no matter what I do my charts always end up being grey.

As a toy example, if I run this:

Year <- c(2015,2015,2015,2015,2016,2016,2017,2017,2017,2017)
Class <- c(2,1,2,3,2,3,1,2,3,2)
Data <- data.frame(Year,Class)

ggplot(Data, aes(Year)) +
  geom_bar(aes(fill=Class))

I get the following (very grey) chart:

Grey Chart

Every ggplot tutorial I have found suggests that I should get something more colourful that looks like a stacked bar chart. Any suggestions? I am a complete novice, so there's a fair chance it's my fault.

Upvotes: 2

Views: 2683

Answers (1)

P1storius
P1storius

Reputation: 947

use stat='identity' and a table of counts per group. Then use position='stack' to stack bars while preserving grouping information based on the Class

Default stat='count', which means ggplot counts the number of times each value (here, Year), occurs, but it does not take into account any other grouping variables. stat='identity' means ggplot reads the values as actual bar heights.

melt() from reshape2 reformats the table() output into long format which ggplot is able to read

library(ggplot2)
 library(reshape2)
 Year <- c(2015,2015,2015,2015,2016,2016,2017,2017,2017,2017)
 Class <- c(2,1,2,3,2,3,1,2,3,2)
 Data <- data.frame(Year,Class)


Data2 <- melt(table(Data))

 ggplot(mpg, aes(class)) +
  geom_bar(aes(fill = drv))

 ggplot(Data2, aes(x=Year, y=value)) +
  geom_bar(aes(fill = as.factor(Class)), position='stack',  stat='identity')

Upvotes: 2

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