How to change legend title in ggplot

Question

I have the following plot like below. It was created with this command:

library(ggplot2) df <- data.frame(cond = factor(rep(c("A", "B"), each = 200)), rating = c(rnorm(200), rnorm(200, mean=.8))) ggplot(df, aes(x=rating, fill=cond)) + geom_density(alpha = .3) + xlab("NEW RATING TITLE") + ylab("NEW DENSITY TITLE")

Now, I want to modify the legend title from cond into NEW LEGEND TITLE.

So, I just added the following line add the end of the above code:

+labs(colour="NEW LEGEND TITLE")

But it doesn't work. What's the right way to do it?

enter image description here

For those looking for an answer involving plots with multiple geom_ statements, I recommend the answer at stackoverflow.com/a/38485985/1169233, it's the only one that worked for me. — Waldir Leoncio
– Waldir Leoncio, Commented Feb 20, 2020 at 13:06
Just note that for other types of graphs (when you use 'colour' in aes instead of 'fill') the OP question code would already work. 'Colour' is already right and not "fill"! I was going crazy trying all the answers and my solution was in the question! ;) — Juan C
– Juan C, Commented Apr 26, 2020 at 17:09

Arun · Accepted Answer · 2013-01-31 09:35:43Z

605

Answer recommended by R Language Collective

This should work:

p <- ggplot(df, aes(x=rating, fill=cond)) + geom_density(alpha=.3) + xlab("NEW RATING TITLE") + ylab("NEW DENSITY TITLE") p <- p + guides(fill=guide_legend(title="New Legend Title"))

(or alternatively)

p + scale_fill_discrete(name = "New Legend Title")

answered Jan 31, 2013 at 9:35

Arun

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7 Comments

Alex Holcombe Over a year ago

Another alternative is p$labels$fill <- "New Legend Title"

Medhat Over a year ago

what is the difference between guides and scale_fill_discrete

ClementWalter Over a year ago

p$labels$fill didn't work for me. With ggplot2_2.1.0 I use p$labels$colour <- "New legend title"

discipulus Over a year ago

p$labels$fill is nice but if you are using more than one variable in aesthetic (linetype, color, shape) in aes, you have to change them for each separately.

AndrewGB Over a year ago

Many of the scale_fill_... functions can take name as one of the parameters. I was able to use: scale_fill_gradientn(colors = custom_colors, na.value = "transparent", name = "New Legend Title") in my ggplot chain.

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Jean-François Fabre · Accepted Answer · 2019-05-03 20:35:43Z

475

I didn't dig in much into this but because you used fill=cond in ggplot(),

 + labs(color='NEW LEGEND TITLE')

might not have worked. However it you replace color by fill, it works!

+ labs(fill='NEW LEGEND TITLE')

This worked for me in ggplot2_2.1.0

edited May 3, 2019 at 20:35

Jean-François Fabre♦

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answered Aug 14, 2016 at 3:04

Rohan

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5 Comments

Dan Over a year ago

both color= and fill= should work. This is the "right" answer to the question, IMO

user1442363 Over a year ago

whether colour of fill would work depends on what "cond" (or group in other cases) is really mapped to. A good explanation could be found in cookbook-r.com/Graphs/Legends_(ggplot2)

Sumax Over a year ago

Note: in ggplot2 3.0+ this solution didn't work: solved it by p + guides(fill=guide_legend(title="New Legend Title"))

xm1 Over a year ago

with a grouping variable (that needs to be a factor), only labs(color='NEW LEGEND TITLE') worked for me

arranjdavis Over a year ago

This also works with labs(size='NEW LEGEND TITLE') if you are using geom_point(aes(size = some_size)) .

user1317221_G · Accepted Answer · 2013-01-31 09:39:55Z

Since you have two densitys I imagine you may be wanting to set your own colours with scale_fill_manual.

If so you can do:

df <- data.frame(x=1:10,group=c(rep("a",5),rep("b",5))) legend_title <- "OMG My Title" ggplot(df, aes(x=x, fill=group)) + geom_density(alpha=.3) + scale_fill_manual(legend_title,values=c("orange","red"))

enter image description here

Rohit Yadav · Accepted Answer · 2018-07-25 15:54:46Z

56

None of the above code worked for me.

Here's what I found and it worked.

labs(color = "sale year")

You can also give a space between the title and the display by adding \n at the end.

labs(color = 'sale year\n")

answered Jul 25, 2018 at 15:54

Rohit Yadav

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5 Comments

merv Over a year ago

How is this any different than this answer?

SummerEla Over a year ago

Yep, I tried every single example above and this is the only one that worked for me. Thanks!

steveb Over a year ago

How would this work given the original post question, it seems that fill instead of color (or colour) is needed? Given the time of the question, it is possible it is ggplot2 version related.

Luís de Sousa Over a year ago

@merv The main difference is that this one actually works.

ibilgen Over a year ago

This is all about how you group your data and create legend based on it. If you use linetype like in ggplot(data=df, aes(x=time, y=value, linetype=variable)) then labs(linetype = 'sale year\n") will work for you.

kulianne · Accepted Answer · 2017-08-16 15:48:14Z

Since in your code you used ggplot(data, fill= cond) to create the histogram you need to add the legend title by also using "fill" in the label section i.e. +labs(fill="Title name"). If you were using a different type of plot where the code was ggplot(data, colour= cond), then you could use +labs(colour= "Title Name"). In summary, the lab argument has to match the aes argument.

I have used + guides(fill=guide_legend("my awesome title")) to change the legend title on geom_bar plots but it did not seem to work for geom_point.

..., but for geom_point(), this works for me: guides(color=guide_legend("Type:"))
@knb, your method works: guides(color=guide_legend("Score Ranking:"))

Yourpalal · Accepted Answer · 2017-07-24 15:59:22Z

There's another very simple answer which can work for some simple graphs.

Just add a call to guide_legend() into your graph.

ggplot(...) + ... + guide_legend(title="my awesome title")

As shown in the very nice ggplot docs.

If that doesn't work, you can more precisely set your guide parameters with a call to guides:

ggplot(...) + ... + guides(fill=guide_legend("my awesome title"))

You can also vary the shape/color/size by specifying these parameters for your call to guides as well.

This did not work for me, but qplot(…) + guides(color=guide_legend(title="sale year")) worked
merci @ArnaudA only your option worked for me with the plots generated by the dyno trajectory inference package

user438383 · Accepted Answer · 2023-09-21 11:50:32Z

Alas, none of these solutions worked for me. I am working with output from brms::conditional_effects()

My solution required:

+ labs( fill = "New Title", colour = "New Title", labels = "New Title" )

Birdonawire · Accepted Answer · 2017-09-20 11:24:52Z

7

I am using a facet_wrap in my ggplot and none of the suggested solutions worked for me except ArnaudA's solution:

qplot(…) + guides(color=guide_legend(title="sale year"))

answered Sep 20, 2017 at 11:24

Birdonawire

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1 Comment

Teddy Over a year ago

Hey thanks, this worked for my case too. I was using a legend in a line plot. So i was using group and not fill. Due to that all the other solutions didn't work for me too.

Eric Leung · Accepted Answer · 2020-03-25 19:54:21Z

Just to add to the list (the other options here didn't work for me), you can also use the function update_labels for ggplot:

p <- ggplot(df, aes(x=rating, fill=cond)) + geom_density(alpha=.3) + xlab("NEW RATING TITLE") + ylab("NEW DENSITY TITLE")

update_labels(p, list(colour="MY NEW LEGEND TITLE")

This will also allow you to change x- and y-axis labels, with separate lines:

update_labels(p, list(x="NEW X LABEL",y="NEW Y LABEL")

user438383 · Accepted Answer · 2024-07-12 09:24:00Z

4

The only solution that works with me : p + guides(fill=guide_legend("New title"))

edited Jul 12, 2024 at 9:24

user438383

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answered Oct 14, 2021 at 9:32

Ayoub EL MAJJODI

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5 Comments

Angela Russell Over a year ago

What if you wanted to keep the legend title but change the labels for each item/variable in the legend? For example, how would you change A to Alpha and B to Beta?

Ayoub EL MAJJODI Over a year ago

I think if I got you question correct, legend is taken from you dataframe, so In the worst cases you can use map function with new to rename variable of you legend

Angela Russell Over a year ago

would you mind providing a little example of how that script would look to apply the change with the map function stackoverflow.com/users/7739509/ayoub-el-majjodi

Angela Russell Over a year ago

Also worked: mutate(cond = recode(cond, "A" = "Alpha", "B" = "Beta")) %>%

Ayoub EL MAJJODI Over a year ago

like this, if we want to rename legends in one column: new_names = {"A":"Alpha", "B":"Beta"} df['new_legends']= df['old_legend'].map(new_names) We will have a new column and then choose which one you can use a legend

Matt Ke · Accepted Answer · 2020-06-30 15:59:50Z

Adding this to the mix, for when you have changed the colors. This also worked for me in a qplot with two discrete variables:

p+ scale_fill_manual(values = Main_parties_color, name = "Main Parties")

GAURAV JOSHI · Accepted Answer · 2020-10-19 07:54:54Z

The way i am going to tell you, will allow you to change the labels of legend, axis, title etc with a single formula and you don't need to use memorise multiple formulas. This will not affect the font style or the design of the labels/ text of titles and axis.

I am giving the complete answer of the question below.

 library(ggplot2) rating <- c(rnorm(200), rnorm(200, mean=.8)) cond <-factor(rep(c("A", "B"), each = 200)) df <- data.frame(cond,rating ) k<- ggplot(data=df, aes(x=rating, fill=cond))+ geom_density(alpha = .3) + xlab("NEW RATING TITLE") + ylab("NEW DENSITY TITLE") # to change the cond to a different label k$labels$fill="New Legend Title" # to change the axis titles k$labels$y="Y Axis" k$labels$x="X Axis" k

I have stored the ggplot output in a variable "k". You can name it anything you like. Later I have used

k$labels$fill ="New Legend Title"

to change the legend. "fill" is used for those labels which shows different colours. If you have labels that shows sizes like 1 point represent 100, other point 200 etc then you can use this code like this-

k$labels$size ="Size of points"

and it will change that label title.

Good Fit · Accepted Answer · 2019-11-28 11:17:45Z

I noticed there are two ways to change/specify legend.title for ggboxplot():

library(ggpubr) bxp.defaultLegend <- ggboxplot(ToothGrowth, x = "dose", y = "len", color = "dose", palette = "jco") # Solution 1, setup legend.title directly in ggboxplot() bxp.legend <- ggboxplot(ToothGrowth, x = "dose", y = "len", color = "dose", palette = "jco", legend.title="Dose (mg)") # Solution 2: Change legend title and appearnace in ggboxplot() using labs() and theme() option: plot1 <- bxp.defaultLegend + labs(color = "Dose (mg)") + theme(legend.title = element_text(color = "blue", size = 10), legend.text = element_text(color = "red")) ggarrange(list(bxp.legend, bxp.defaultLegend, plot1), nrow = 1, ncol = 3, common.legend = TRUE)

The code is modified based on the example from GitHub.

Nakx · Accepted Answer · 2019-02-02 05:09:32Z

Many people spend a lot of time changing labels, legend labels, titles and the names of the axis because they don't know it is possible to load tables in R that contains spaces " ". You can however do this to save time or reduce the size of your code, by specifying the separators when you load a table that is for example delimited with tabs (or any other separator than default or a single space):

read.table(sep = '\t')

or by using the default loading parameters of the csv format:

read.csv()

This means you can directly keep the name "NEW LEGEND TITLE" as a column name (header) in your original data file to avoid specifying a new legend title in every plot.

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