[R] stacked plot

[Dennis Murphy]

It appears that your object is currently a matrix. Here's a toy
example to illustrate how to get a stacked bar chart in ggplot2:

library('ggplot2')
m <- matrix(1:9, ncol = 3, dimnames = list(letters[1:3], LETTERS[1:3]))
(d <- as.data.frame(as.table(m)))
  Var1 Var2 Freq
1    a    A    1
2    b    A    2
3    c    A    3
4    a    B    4
5    b    B    5
6    c    B    6
7    a    C    7
8    b    C    8
9    c    C    9

ggplot(d, aes(x = Var1, y = Freq, fill = Var2)) +
   geom_bar(position = 'stack', stat = 'identity') +
   labs(x = 'Variable 1', y = 'Frequency', fill = 'Group') +
   scale_fill_manual(values = c('A' = 'red', 'B' = 'blue', 'C' = 'green'))

This plot uses Var1 as the x-variable, Freq as the response and Var2
as the variable whose frequencies are to be stacked, distinguished by
fill color. position = 'stack' designates the stacking while stat =
'identity' indicates that the y variable Freq should be used to
represent the counts.
labs()  designates the labels for each axis; the fill = label
indicates the legend title for the fill colors. Finally, the
scale_fill_manual() function is used to manually assign specific
colors to levels of the fill variable Var2. The scale_fill_manual()
code could also have been written as

... +
scale_fill_manual(breaks = levels(d$Var2), values = c('red', 'blue', 'green'))

with the same result.

HTH,
Dennis

On Thu, Oct 20, 2011 at 10:08 PM, Henri-Paul Indiogine
<hindiogine at gmail.com> wrote:
> Hi!
>
> I am trying to use ggplot2 to create a stacked bar plot.  Previously I
> tried using barplot() but gave up because of problems with the
> positioning of the legend and other appearance problems.   I am now
> trying to learn ggplot2 and use it for all the plots that I need to
> create for my dissertation.
>
> I am able to create normal bar plots using ggplot2, but I am stomped
> with the stacked bar plots.
>
> This works:
>
> barplot(t(file.codes), beside = FALSE)
>
> the data.frame file.codes looks like this .....
>
>        code.1 code.2 code.3 code.4 code.5 ....
> file.1      2       0         0         5        4      ....
> file.2      3       18       1         0        2      ....
> ....
>
> I would like each file to be a bar and then each code stacked for each
> file.    By transposing the file.codes data.frame barplot() will allow
> me to do so.   I am trying to obtain the same result in ggplot2  but i
> think that qplot wants the data to be like this:
>
> file.1 code.1  2
> file.1 code.2  0
> file.1 code.3  0
> file.1 code.4  5
> file.1 code.5  4
> file.2 code.1  3
> file.2 code.2  18
> ....
>
> I think that I need to use the package "reshape", but I am not sure
> whether to use cast(), melt(), or recast() and how to set up the
> function.
>
> Thanks,
> Henri-Paul
>
>
> --
> Henri-Paul Indiogine
>
> Curriculum & Instruction
> Texas A&M University
> TutorFind Learning Centre
>
> Email: hindiogine at gmail.com
> Skype: hindiogine
> Website: http://people.cehd.tamu.edu/~sindiogine
>
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