(This article was first published on

Sometimes when plotting factor variables in R, the graphics can look pretty messy thanks to long factor levels. If the level attributes have multiple words, there is an easy fix to this that often makes the axis labels look much cleaner.**Mollie's Research Blog**, and kindly contributed to R-bloggers)### Without Line Breaks

Here's the messy looking example:No line breaks in axis labels |

And here's the code for the messy looking example:

library(OIdata)

data(birds)

library(ggplot2)

levels(birds$effect) <- gsub(" ", "\n", levels(birds$effect))

ggplot(birds,

aes(x = effect,

y = speed)) +

geom_boxplot()

### With Line Breaks

We can use regular expressions to add line breaks to the factor levels by substituting any spaces with line breaks:

library(OIdata)

data(birds)

library(ggplot2)

levels(birds$effect) <- gsub(" ", "\n", levels(birds$effect))

ggplot(birds,

aes(x = effect,

y = speed)) +

geom_boxplot()

Line breaks in axis labels |

### Horizontal Boxes

Here we can see the difference in a box plot with horizontal boxes. It's up to you to decide which style looks better:No line breaks in axis labels |

Line breaks in axis labels |

library(OIdata)

data(birds)

library(ggplot2)

levels(birds$effect) <- gsub(" ", "\n", levels(birds$effect))

ggplot(birds,

aes(x = effect,

y = speed)) +

geom_boxplot() +

coord_flip()

Just a note: if you're not using

**ggplot**, the multi-line axis labels might overflow into the graph.

The code is available in a gist.

### Citations and Further Reading

To

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