[R] How to wrap or split labels on plot

[Uwe Ligges]

Marc Schwartz wrote:

> On Fri, 2004-12-03 at 15:00 -0500, Heather J. Branton wrote:
> 
>>Dear R gurus,
>>
>>I want to wrap labels that are too long for a plot. I have looked at 
>>strsplit(), substr(), nchar(), and strwrap(). I think it's some 
>>combination but I'm having difficulty trying to figure out the right 
>>combo. I think I need to create some new matrix containing the labels 
>>already split, though I'm not sure if maybe there is a quick and dirty 
>>way to address this without my wandering around the block.
>>
>>I am using R 1.9.1, Windows XP.  (Note:  we are currently in the midst 
>>of a big project and probably won't upgrade to R 2.0.1 for another 
>>couple of weeks -- *unless* that's what I need to do to address these 
>>issues.)
>>
>>Here is my script with two label options at the bottom that are not working.
>>
>># Settings
>>win.graph(width=8, height=8, pointsize=10)
>>
>># Read in data
>>test <- matrix(data=c(2.52,9.5,3.07,2.5,1.99,8.95), nrow = 6, byrow=TRUE)
>>
>># Read in and attach labels (names) to data
>>rownames(test) <- c("Mount Pleasant","Jordan","Oil City","Pleasant 
>>Valley","Village of Lake Isabella","Rosebush")
>>
>># Set plot limits:
>>xmax <- nrow(test)
>>nvec <- ncol(test)
>>ymax <- ceiling(max(test))
>>yinc <- 1
>>
>># Generate Pareto order
>>test <- test[order(test[,1],decreasing=TRUE),]
>>
>># Set color palette
>>MyCols <- rep(c("lightcyan","cornsilk","lavender"), each = xmax)
>>
>># Adjust the margins
>>par(mar = c(7, 5, 6, 3))
>>
>># Bar graph
>>mp <- barplot(test, beside = TRUE,
>>    col = MyCols,
>>    axisnames = FALSE,
>>    names.arg = rep(names(test),nvec),
>>    las = 2,
>>    cex.names = 0.75,
>>    ylab = "IXYV",
>>    ylim = c(0,ymax),
>>    yaxt = "n")
>>
>># Set up the y axis tick marks and labels
>>ifelse (ymax<=10,decpt <- 2,decpt <- 0)
>>ticks <- seq(0, ymax, yinc)
>>axis(2, at = ticks, las = 1,
>>     labels = formatC(ticks, format = "f", digits = decpt))
>>
>># Draw a box around the whole thing
>>box()
>>
>># Draw the x axis labels
>>mtext(side = 1, at = rowMeans(mp)-.2, line = .5, las=2, text = 
>>strsplit(names(test)," "))
>>mtext(side = 1, at = rowMeans(mp), line = .5, las=2, text = 
>>strwrap(names(test),7))
>>mtext(side = 1, line = 5.5, text = "Division")
>>
>># Draw titles
>>title(main="Central", outer=F, font.main=4, line=4)
>>title(main="IXYV by Division", outer=F, font.main=2, line=2.5)
> 
> 
> 
> Heather,
> 
> There is likely to be more than one approach, but the one that I
> generally use is to explicitly put a newline character "\n" into the
> plot labels where required. So, in this case, you could do something
> like:
> 
> names(test) <- c("Mount\nPleasant","Jordan","Oil City",
>                  "Pleasant\nValley",
>                  "Village of\nLake Isabella",
>                  "Rosebush")
> 


... or automatically by combining strwrap() and paste():

   names(test) <-
     sapply(lapply(names(test), strwrap, 15),
       paste, collapse = "\n")

Uwe Ligges



> Also, there are some confusing things in your code, which I suspect may
> tie back to your test data versus the actual data you are using. If I am
> missing something here, you might want to clarify that, since things
> like your colors and other things don't entirely make sense.
> 
> Here is something of a simplified approach using the test data as you
> have it:
> 
> # Test can be a vector
> test <- c(2.52, 9.5, 3.07, 2.5, 1.99, 8.95)
> 
> names(test) <- c("Mount\nPleasant","Jordan","Oil City",
>                  "Pleasant\nValley",
>                  "Village of\nLake Isabella",
>                  "Rosebush")
> 
> # Use sort here
> test <- sort(test, decreasing = TRUE)
> 
> ymax <- ceiling(max(test))
> 
> par(mar = c(7, 5, 6, 3))
> 
> # Note that you can use the names here for names.arg
> # As a result of the "\n", the titles will print on two lines
> mp <- barplot(test, names.arg = names(test),  
>               cex.names = 0.8, ylab = "IXYV", 
>               yaxt = "n", ylim = c(0, ymax))
> 
> ticks <- seq(0, ymax, 1)
> axis(2, at = ticks, las = 1,
>      labels = formatC(ticks, format = "f",
>                       digits = ifelse(ymax <= 10, 2, 0)))
> 
> box()
> 
> mtext(side = 1, line = 3.5, text = "Division")
> 
> # you can combine the two title() calls into one mtext() call
> mtext(side = 3, text = c("Central", "IXYV by Division"),
>       font = c(4, 2), line = c(4, 2.5))
> 
> 
> 
> If your actual data is a more complex matrix, adjust the above
> accordingly.
> 
> HTH,
> 
> Marc Schwartz
> 
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