ggplot stacked bar plot from 2 separate data frames

yield <- rbind(transform(pure, mix = Var), transform(mixt, mix = 'Mixed'))
ggplot(yield, aes(x=mix, y=mean, fill=Var)) +
  geom_bar(stat="identity")

ggplot() + 
  geom_bar(data = transform(pure, mix = Var), aes(x=mix, y=mean, fill=Var), stat="identity") +
  geom_bar(data = transform(mixt, mix = 'Mixed'), aes(x=mix, y=mean, fill=Var), stat="identity") 

ggplot() + 
  mapply(function(x, type) 
    geom_bar(data = transform(x, mix = type), 
      aes(x=mix, y=mean, fill=Var), stat="identity"), 
    list(pure, mixt), 
    list(pure$Var, 'Mixed'))

ggplot(d, aes(x = Day, y = Length)) + 
  geom_bar(aes(fill = Amount, order = -Location), stat = "identity")

newDF <- do.call(rbind, list.df)
newDF$id <- factor(rep(1:length(df.list), each = sapply(df.list, nrow)))
g <- geom(newDF, aes(x = dX, y = dY, colour = id)
g <- g + geom_line()
print(g)

ggplot(data=df, aes(x=x, y=y)) + 
  geom_point(aes(color="Weekly Forecast"), shape=16, size = 5)  + 
  geom_line(color="red", size=1)  + 
  geom_point(data=df2, aes(color="Main Forecast"), shape=21, fill = "white", size = 5)  +
  scale_color_manual("Legend Title", limits=c("Weekly Forecast", "Main Forecast"), values = c("red","red")) +
  guides(colour = guide_legend(override.aes = list(pch = c(16, 21), fill = c("red", "white"))))

ggplot(data=df, aes(x=x, y=y)) + 
  geom_line(aes(color="Main Forecast"), size=1)  + 
  geom_point(aes(color="Weekly Forecast", fill="Weekly Forecast"), shape=21, size = 5)  +
  geom_point(data=df2, aes(color="Main Forecast", fill="Main Forecast"), shape=21, size = 5)  +
  scale_color_manual(name="", values = c("red","red")) +
  scale_fill_manual(name="", values=c("white","red"))

dat = aggregate(list(value = 1:NROW(df)), df[c("age_group", "Gender")], length)
dat$proportion = ave(dat$value, dat$age_group, FUN = function(x) x/sum(x))
ggplot(dat, aes(x = age_group, y = proportion, fill = Gender)) +
    geom_col() +
    coord_flip()