How to reshape data for a stacked barchart using R lattice [duplicate]

Answer 1

Supposing your data is in a dataframe called df, you can do that with the help of the dplyr and tidyr packages:

library(dplyr)
library(tidyr)

wide <- df %>% select(date,classes) %>%
  group_by(date,classes) %>%
  summarise(n=n()) %>%            # as @akrun said, you can also use tally()
  spread(classes, n, fill=0)

Using the example data you provided, this results in the following dataframe:

  date english french spanish
9/1/11       1      2       1
9/2/11       1      1       0
9/3/11       0      0       2
9/5/11       2      1       1

Now you can make a lattice plot with:

barchart(date ~ english + french + spanish, data=wide, stack = TRUE,
         main = list(label="Distribution of language classes",cex=1.6),
         xlab = list("Number of classes", cex=1.1),
         ylab = list("Date", cex=1.1),
         auto.key = list(space='right',cex=1.2,text=c('Enligsh','French','Spanish')))

which gives the following plot:

---

EDIT: Instead of using lattice-plots, you can also use ggplot2, which is (at least in my opinion) easier to understand. An example:

# convert the wide dataframe to a long one
long <- wide %>% gather(class, n, -date)

# load ggplot2
library(ggplot2)

# create the plot
ggplot(long, aes(date, n, fill=class)) +
  geom_bar(stat="identity", position="stack") +
  coord_flip() +
  theme_bw() +
  theme(axis.title=element_blank(), axis.text=element_text(size=12))

which gives:

Answer 2

I hope I'm not missing anything, but it looks to me like you're just looking for table:

table(df[c("date", "classes")])
#         classes
# date     english french spanish
#   9/1/11       1      2       1
#   9/2/11       1      1       0
#   9/3/11       0      0       2
#   9/5/11       2      1       1

The result is a table (which is also a matrix) so you can use your barchart command as you wish.

Here's what I get--looks like you need to work on your legend :-)

The code used was:

language <- table(df[c("date", "classes")])

barchart(prop.table(language), 
         horizontal = FALSE, 
         auto.key = list(space = 'right',
                         cex = .5, border = T, points = F, 
                         lines = F, lwd = 5, 
                         text = c('french','spanish','enligsh'),
                         cex = .6), 
         main = list(label = "Distribution of classes 10", cex = 2.5),
         ylab = list("", cex = 1.7), 
         xlab.top = list("testing", cex = 1.2))