CODEWITHSUNDEEP
rggplot2
user3022875
user3022875

Reputation: 9018

Setting the x-axis for R ggplot2

How can I make the x-axis display the text in the "xaxisTitles" vector?

Here is my code you can run:

require(ggplot2)
require(reshape)

xaxisTitles<- cbind("a","b","c","d","e","f","g","h","j","k")
df <- data.frame(time = 1:10,
             a = cumsum(rnorm(10)),
             b = cumsum(rnorm(10)),
             c = cumsum(rnorm(10)))
df <- melt(df ,  id = 'time', variable_name = 'series')

# plot on same grid, each series colored differently -- 
# good if the series have same scale
ggplot(df, aes(time,value)) + geom_line(aes(colour = series))+ theme(axis.text.x =     xaxisTitles)

I am getting the error:

Error in (function (el, elname)  : 
  Element axis.text.x must be a element_text object.

Upvotes: 2

Views: 7981

Answers (3)

jlhoward
jlhoward

Reputation: 59355

The reason you are getting the error is that theme(...) is used to set the appearance of the axis text (e.g., color, font family, font face, size, orientation, etc.), but not the values of the text. To do that, as @SteveReno points out, you have to use scale_x_discrete(...).

require(ggplot2)
require(reshape)
set.seed(321)
# xaxisTitles<- cbind("a","b","c","d","e","f","g","h","j","k")
xaxisTItles<- letters[1:10]   # easier way to do this...
df <- data.frame(time = 1:10,
                 a = cumsum(rnorm(10)),
                 b = cumsum(rnorm(10)),
                 c = cumsum(rnorm(10)))
df <- melt(df ,  id = 'time', variable_name = 'series')

# plot on same grid, each series colored differently -- 
# good if the series have same scale
ggplot(df, aes(time,value)) + 
  geom_line(aes(colour = series))+ 
  scale_x_discrete(labels=xaxisTitles)+
  theme(axis.text.x=element_text(face="bold",colour="red",size=14))

Upvotes: 5

Steve Reno
Steve Reno

Reputation: 1384

You can just use scale_x_discrete to set the labels.

ggplot(df, aes(time,value)) + geom_line(aes(colour = series))+ scale_x_discrete(labels= xaxisTitles)

Here's some more helpful info http://docs.ggplot2.org/0.9.3.1/scale_discrete.html

Upvotes: 2

David Robinson
David Robinson

Reputation: 78600

The best way to do this is to make the time variable a factor rather than a numeric vector, as long as you remember to adjust the group aesthetic:

df$time = factor(xaxisTitles[df$time])
ggplot(df, aes(time, value)) + geom_line(aes(colour = series, group=series))

(If you don't add the group=series argument, it won't know that you want to connect lines across the factor on the x axis).

Upvotes: 2

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