How to change legend title in ggplot

Question

I have the following plot like below   It was created with this command   library ggplot2   df  lt - 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 next thing I want to do is to modify the legend title from cond into NEW LEGEND TITLE   So what  I did is to just add 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

User · Answer

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

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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  lt - c rnorm 200   rnorm 200  mean  8    cond  lt -factor rep c  quot A quot    quot B quot    each   200    df  lt - data frame cond rating                   k lt - ggplot data df  aes x rating  fill cond      geom density alpha    3     xlab  quot NEW RATING TITLE quot      ylab  quot NEW DENSITY TITLE quot       to change the cond to a different label  k labels fill  quot New Legend Title quot      to change the axis titles  k labels y  quot Y Axis quot   k labels x  quot X Axis quot   k  I have stored the ggplot output in a variable  quot k quot   You can name it anything you like  Later I have used k labels fill   quot New Legend Title quot   to change the legend   quot fill quot  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   quot Size of points quot   and it will change that label title

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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    quot Main Parties quot

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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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This should work   p  lt - ggplot df  aes x rating  fill cond                 geom density alpha  3                xlab  NEW RATING TITLE                 ylab  NEW DENSITY TITLE   p  lt - p   guides fill guide legend title  New Legend Title       or alternatively   p   scale fill discrete name    New Legend Title

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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  lt - 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

User · Answer

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

User · Answer

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

User · Answer

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

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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  lt - data frame x 1 10 group c rep  a  5  rep  b  5     legend title  lt -  OMG My Title   ggplot df  aes x x  fill group     geom density alpha  3           scale fill manual legend title values c  orange   red

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I noticed there are two ways to change specify legend title for ggboxplot     library ggpubr   bxp defaultLegend  lt - ggboxplot ToothGrowth  x    dose   y    len                                  color    dose   palette    jco      Solution 1  setup legend title directly in ggboxplot   bxp legend  lt - 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  lt -  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

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ggplot df    labs legend     lt legend title gt

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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

[r] How to change legend title in ggplot

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