Displaying a greater than or equal sign
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.
You can pass an expression (including phantom(...) to fake a leading >= withinthe 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 andthis related SO question and answer
