Displaying a greater than or equal sign

Question

I have a plot which is generated thus:

ggplot(dt.2, aes(x=AgeGroup, y=Prevalence)) + 
    geom_errorbar(aes(ymin=lower, ymax=upper), colour="black", width=.2) +
    geom_point(size=2, colour="Red")

I control the x axis labels like this:

scale_x_discrete(labels=c("0-29","30-49","50-64","65-79",">80","All")) +

This works but I need to change the ">80" label to "≥80".

However "≥80" is displayed as "=80".

How can I display the greater than or equal sign ?

Solution 1

An alternative to using expressions is Unicode characters, in this case Unicode Character 'GREATER-THAN OR EQUAL TO' (U+2265). Copying @mnel's example

.d <- data.frame(a = letters[1:6], y = 1:6)

ggplot(.d, aes(x=a,y=y)) + geom_point() + 
    scale_x_discrete(labels = c(letters[1:5], "\u2265 80"))

Unicode is a good alternative if you have trouble remembering the complicated expression syntax or if you need linebreaks, which expressions don't allow. As a downside, whether specific Unicode characters work at all depends on your graphics device and font of choice.

Solution 2

You can pass an expression (including phantom(...) to fake a leading >= within the label argument to scale_x_discrete(...)

for example

 .d <- data.frame(a = letters[1:6], y = 1:6)

 ggplot(.d, aes(x=a,y=y)) + geom_point() + 
    scale_x_discrete(labels = c(letters[1:5], expression(phantom(x) >=80))

See ?plotmath for more details on creating mathematical expressions and this related SO question and answer

Solution 3

plot(5, ylab=expression("T ">="5"))

Solution 4

You can use

expression("">=80)

So your full axis label like would look like:

scale_x_discrete(labels=c("0-29","30-49","50-64","65-79",expression("">=80),"All")) +

I have had trouble exporting plots when using unicode, but the expression function is more consistent.

View more solutions

Comments

[Robert Long]

@JanDvorak, unfortunately not. It's for publication, so it needs to look as good as possible. I wanted to go with >79 but the senior authors specifically wants ≥80

[plannapus]

have you tried expression("">=80)? See ?plotmath.

[Robert Long]

@plannapus - that does the trick nicely ! Thank you - if you make an answer, I will upvote and accept...

[plannapus]

It seems that @mnel was quicker than me :)

[mnel]

I posted before I saw your comment (if that makes it better?)

[plannapus]

And I saw your answer just as I posted my comment!

[MichaelChirico]

Problem: the pdf device does not support this character and prints ... instead. I'm not working in ggplot so maybe this isn't a concern in that package, but it's troublesome for saving from base R.

[otsaw]

@MichaelChirico: Solution: unless you have compelling reason to use pdf, use cairo_pdf instead.

[MichaelChirico]

can you give an example of what such a compelling reason might be?

[Vincent]

@otsaw I have the same problem with the postscript device for producing eps. Is there a cairo_postscript or similiar solution that you know of?

[Nova]

Works within a call to paste, so that's nice!

[tjebo]

This wikipedia site lists all mathematical operators- some of the more common ones are listed at the bottom of the site!

[tjebo]

And this blog gives helpful advice how to use cairo with ggsave

[Amer]

how can we do lower that or equal sign?

[logjammin]

FYI this also works for the forestplot package, for anyone who's just been googling a similarissue!