What's wrong with combining multiple geom_rect ()?
I have a simple dataset, with
tmp
# xmin xmax ymin ymax
# 0 1 0 11
# 0 1 11 18
# 0 1 18 32
And I want all to geom_rect()
appear somewhat in the plot. Here's what I do and everything looks good.
cols = c('red', 'blue', 'yellow')
x = seq(0, 1, 0.05)
ggplot(data = NULL, aes(x = 1, y = 32)) +
geom_rect(data = NULL, aes(xmin=x, xmax = x + 0.05, ymin=0, ymax=11, fill = x), color = cols[1] ) +
geom_rect(data = NULL, aes(xmin=x, xmax = x + 0.05, ymin=11, ymax=18, fill = x), color = cols[2]) +
geom_rect(data = NULL, aes(xmin=x, xmax = x + 0.05, ymin=18, ymax=32, fill = x), color = cols[3])
However, which puts these three geom_rect()
in a loop, I end up with a different plot. The geometry seems to be fused together. Can I tell someone to me what's wrong with the loop code?
g1 = ggplot(data = NULL, aes(x = 1, y = 32))
for (i in 1:3) {
yl = tmp[i, ]$ymin
yu = tmp[i, ]$ymax
g1 = g1 + geom_rect(data = NULL, aes(xmin=x, xmax = x + 0.05, ymin=yl, ymax=yu, fill = x), color = cols[i])
}
g1
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2 answers
Another answer is good. Simple if you really want to stick with your source code. Here is a solution, with a slight modification based on your original.
g1 = ggplot(data = NULL, aes(x = 1, y = 32))
for (i in 1:3) {
yl = tmp[i, 3] ## no need to use $, just column index is fine
yu = tmp[i, 4] ## no need to use $, just column index is fine
## ggplot2 works with data frame. So you convert yl, yu into data frame.
## then it knows from where to pull the data.
g1 = g1 + geom_rect(data=data.frame(yl,yu), aes(xmin=x, xmax=x+0.05, ymin=yl, ymax=yu, fill=x), color=cols[i])
}
g1
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To avoid the caveat described in @MrFlick, you can define data
separately for example, like:
g1 = ggplot(data = NULL)
for (i in 1:3) {
g1 = g1 + geom_rect(data = tmp[i, ],
aes(xmin = x, xmax = x + 0.05,
ymin = ymin, ymax = ymax, fill = x), color = cols[i])
}
g1
and you will get the plot you want.
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