在R中绘制多条迹线

Question

I started learning R for data analysis and, most importantly, for data visualisation.

Since I am still in the switching process, I am trying to reproduce the activities I was doing with Graphpad Prism or Origin Pro in R. In most of the cases everything was smooth, but I could not find a smart solution for plotting multiple y columns in a single graph.

What I usually get from the softwares I use for data visualisations look like this:

Each single black trace is a measurement, and I would like to obtain the same plot in R. In Prism or Origin, this will take a single copy-paste in a XY graph.

I exported the matrix of data (one X, which indicates the time, and multiple Y values, which are the traces you see in the image).

I imported my data in R with the following commands:

library(ggplot2) #loaded ggplot2

Data <- read.csv("Directory/File.txt", header=F, sep="") #imported data
DF <- data.frame(Data) #transformed data into data frame

If I plot my data now, I obtain a series of columns, where the first one (called V1) is the X axis and all the others (V2 to V140) are the traces I want to put on the same graph.

To plot the data, I tried different solutions:

ggplot(data=DF, aes(x=DF$V1, y=DF[V2:V140]))+geom_line()+theme_bw() #did not work

plot(DF, xy.coords(x=DF$V1, y=DF$V2:V140)) #gives me an error

plot(DF, xy.coords(x=V1, y=c(V2:V10))) #gives me an error

I tried the matplot , without success, following the EZH guide:

The code I used is the following: matplot(x=DF$V1, type="l", lty = 2:100)

The only solution I found would be to individually plot a command for each single column, but it is a crazy solution. The number of columns varies among my data, and manually enter commands for 140 columns is insane.

What would you suggest?

Thank you in advance.

Here there are also some data attached. Data: single X, multiple Y

Answer 1

I tried using the matplot(). I used a very sample data which has no trend at all. so th eoutput from my code shall look terrible, but my main focus is on the code. Since you have already tried matplot() ,just recheck with below solution if you had done it right!

set.seed(100)
df = matrix(sample(1:685765,50000,replace = T),ncol = 100)
colnames(df)=c("x",paste0("y", 1:99))
dt=as.data.frame(df)
matplot(dt[["x"]], y = dt[,c(paste0("y",1:99))], type = "l")

Answer 2

If you want to plot in base R , you have to make a plot and add lines one at a time, however that isn't hard to do.

we start by making some sample data. Since the data in the link seemed to all be on the same scale, I will assume your data frame only has y values and the x value is stored separately.

plotData <- as.data.frame(matrix(sort(rnorm(500)),ncol = 5))
xval <- sort(sample(200, 100))

Now we can initialize a plot with the first column.

plot(xval, plotData[[1]], type = "l", 
     ylim = c(min(plotData), max(plotData)))

• type = "l" makes a line plot instead of a scatter plot
• ylim = c(min(plotData), max(plotData)) makes sure the y-axis will fit all the data.

Now we can add the rest of the values.

apply(plotData[-1], 2, lines, x = xval)

• plotData[-1] removes the column we already plotted,
• apply function with 2 as the second parameter means we want to execute a function on every column,
• lines defines the function we are apply ing to the columns. lines adds a new line to the current plot.
• x = xval passes an extra parameter ( x ) to the lines function.

Answer 3

if you wat to plot the data using ggplot2, the data should be transformed to long format;

library(ggplot2)
library(reshape2)

dat <- read.delim('AP.txt', header = F)

# plotting only first 9 traces
# my rstudio will crach if I plot the full data;
df <- melt(dat[1:10], id.vars = 'V1')

ggplot(df, aes(x = V1, y = value, color = variable)) + geom_line()

# if you want all traces to be in same colour, you can use
ggplot(df, aes(x = V1, y = value, group = variable)) + geom_line()