How do I plot this data using R? - r

Question

> aggregate(dat[, 3:7], by=list(dat$TRT), FUN=mean)
Group.1 DBP1 DBP2 DBP3 DBP4 DBP5
1 A 116.55 113.5 110.70 106.25 101.35
2 B 116.75 115.2 114.05 112.45 111.95
I wish to create a lines plot were the x-axis are the names (DBP1, DBP2, ..., DBP5).
It takes two seconds in Excel (I admit) and gives exactly what I want:
To be clear, the question is about getting the two rows of data into the plot, not about how they are displayed (i.e. with what line/point/color combination).

Answer 1

With dplyr, tidyr and ggplot2
Data
zz <- "Group.1 DBP1 DBP2 DBP3 DBP4 DBP5
A 116.55 113.5 110.70 106.25 101.35
B 116.75 115.2 114.05 112.45 111.95"
df <- read.table(text = zz, header = TRUE)
Load Required Packages
library(dplyr)
library(tidyr)
library(ggplot2)
Tidy
df_tidy <- df %>%
gather(key, value, -Group.1)
Plot
ggplot(data = df_tidy, aes(x = key, y = value)) +
geom_line(aes(color = Group.1)) +
ylim(90, 120)
Output

Answer 2

First step: use melt from the reshape2 package:
d <- aggregate(
dat[, 3:7],
by=list(dat$TRT),
FUN=mean
)
m <- melt(d
id="TRT",
measure.vars=c("DBP1","DBP2","DBP3","DBP4","DBP5")
)
Then use
xyplot(m$value~m$variable, type="o", group=m$TRT, auto.key=list(TRUE))

Answer 3

Simplest possible (??) base-R answer:
dd <- read.table(header=TRUE,text="
Group.1 DBP1 DBP2 DBP3 DBP4 DBP5
A 116.55 113.5 110.70 106.25 101.35
B 116.75 115.2 114.05 112.45 111.95")
matplot() is the basic function for plotting multiple parallel sequences, but (1) it requires that the series be in columns of a matrix; (2) it can't handle character variables, so you have to drop the first column; (3) if you want the group names as axis labels, you have to add that with a separate axis() command. Unfortunately it's not (that I know of) possible to suppress just one of the axes, so you have to suppress them both (axes=FALSE), then add them both manually.
par(las=1) ## horizontal y-axis labels (cosmetic)
matplot(t(dd[,-1]),type="b",axes=FALSE,
ylab="",ylim=c(90,120),
col=c("red","blue"),pch=16,lty=1)
axis(side=2) ## y-axis (default labels)
axis(side=1,at=1:5,label=names(dd)[-1]) ## x-axis
box() ## bounding box
legend("bottomleft",legend=dd$Group.1,
col=c("red","blue"),lty=1,pch=16)
If you want to dispense with legend, nice tick-marks, etc., then just matplot(t(dd[,-1]),...) will do it.

Answer 4

A simple R code can be:
A <- c(116.55, 113.5, 110.70, 106.25, 101.35)
B <- c(116.75, 115.2, 114.05, 112.45, 111.95)
plot(A, type="n")
axis(1, at=1:5, labels=c("DBP1","DBP2","DBP3","DBP4","DBP5"))
lines(A, col="blue")
lines(B, col="red")
Alternate way:
plot(A, type="l", col="blue")
axis(1, at=1:5, labels=c("DBP1","DBP2","DBP3","DBP4","DBP5"))
lines(B, col="red")

Answer 5

A simple approach is to custom your plot, step-by-step.
First, plot the first line and specify you don't when an x-axis to be drawn. Add the second line.
Add your custom x-axis with the labels you want.
Add points on the values you just plot.
Translate into R :
data <- matrix(c(116.55,113.5,110.7,106.25,101.35,116.75,115.2,114.05,112.45,111.95), nrow=2)
plot(data[1,], type="l", xaxt="n")
axis(1, at=1:5, labels=c("DBP1","DBP2","DBP3","DBP4","DBP5"))
lines(data[2,])
points(data[1,])
points(data[2,])
the xaxt="n" specify that you want no x-axis text.
Here is a good reference : http://www.statmethods.net/advgraphs/axes.html
Then, make it beautiful!
If you want a simpler approach for the future, here is a basic function you can improve
plot.Custom <- function(yy, xLabels, ...){
plot(yy[1,], type="l", xaxt="n", ...)
axis(1, at=1:dim(yy)[2], labels=xLabels)
for(i in 1:dim(yy)[1]){
lines(yy[i,])
points(yy[i,])
}
}
plot.Custom(data, c("DBP1","DBP2","DBP3","DBP4","DBP5"))