Create One Dimensional Scatterplots in R Programming – stripchart() Function

Strip Chart is defined as one dimensional scatter plots or dot plots which is used as an alternative to box plot when sample sizes are small. It is created using the stripchart() function in R Language.

R – stripchart Function

Syntax: stripchart(x, data = NULL method, jitter )

Parameters:

• x : value of data from which the plots are to be produced.
• data : a data.frame from which the variables in x value should be taken.
• Method : the method is basically used to separate coincident points.
• jitter : when method = “jitter” is used, jitter will produce the amount of jittering applied. 
  

Stripchart Function in R Programming Language

This example makes use of ToothGrowth database, stripchart() Function is implemented using ToothGrowth database.

Dataset:

R

ToothGrowth$dose <- as.factor(ToothGrowth$dose)

# Print the first 7 rows
head(ToothGrowth, 7)

Output:

   len supp dose
1  4.2   VC  0.5
2 11.5   VC  0.5
3  7.3   VC  0.5
4  5.8   VC  0.5
5  6.4   VC  0.5
6 10.0   VC  0.5
7 11.2   VC  0.5

The above code will print data set

Example 1: Simple Stripchart in R Programming

R

# Plot len by dose
stripchart(len ~ dose, data = ToothGrowth,
        pch = 22, frame = FALSE)

Output:

Example 2: Plot vertical stripchart in R Programming Language

R

# Vertical plot using method = "jitter"
stripchart(len ~ dose, data = ToothGrowth,
        pch = 16, frame = FALSE, vertical = TRUE,
        method = "jitter")

Output:

Example 3: Change in point shapes (pch) and colors by groups

R

# Change point shapes (pch) and colors by groups
# add main title and axis labels
stripchart(len ~ dose, data = ToothGrowth,
        frame = FALSE, vertical = TRUE,
        method = "jitter", pch = c(16, 19, 18),
        col = c("blue ", "darkgreen", "orange"),
        main = "Length / dose", xlab = "Dose",
           ylab = "Length")

Output:

The above example will add the main title and axis labels and print colored stripcharts.

Example 4: Strip Chart for Multiple Numeric Vectors

In this example, we will use an iris dataset and list that contains the variables and plot stripchart plot.

R

# create list of variables
x <- list('Petal Length' = iris$Petal.Length,
          'Petal Width' = iris$Petal.Width)

# create plot that contains
# one strip chart per variable
stripchart(x,
           main = 'Petal Width & Petal Distributions',
           col = c('Green', 'coral2'),
           method = 'jitter')

Output:

Example : the stripchart() function can be used to create a one-dimensional scatterplot.

R

# Create a sample vector of data
data <- c(10, 15, 20, 22, 25, 30, 32, 35, 40)

# Create a stripchart of the data
stripchart(data, method = "jitter", pch = 20, col = "blue", main = "One-Dimensional Scatterplot")

output :