Plotting of Data using Generic plots in R Programming – plot() Function
In this article, we will discuss how we plot data using Generic plots in R Programming Language using plot() Function.
plot function
plot() function in R Programming Language is defined as a generic function for plotting. It can be used to create basic graphs of a different type.
Syntax: plot(x, y, type)
Parameters
- x and y: coordinates of points to plot
- type: the type of graph to create
Returns: different type of plots
Draw Points using plot() Function in R
R
plot (3, 4) |
Output:
Draw Multiple Points
R
plot ( c (1, 3, 4), c (4, 5 , 8)) |
Output:
Draw Sequences of Points
R
plot (1:20) |
Output:
R program to plot a graph
R
# Values for x and y axis x <- 1:5 y <- x * x # Using plot() function with additional settings plot (x, y, type = "l" , col = "blue" , lwd = 2, xlab = "X-axis" , ylab = "Y-axis" , main = "Quadratic Function" ) # Add grid lines grid () # Add points to highlight data points (x, y, col = "red" , pch = 16) # Add a legend legend ( "topleft" , legend = "y = x^2" , col = "blue" , lty = 1, lwd = 2, pch = 16) |
Output:
In this code we creates a line plot with labeled axes, a title, grid lines, and additional points.
col
: Specifies the color of the line,lwd
: Sets the line width,xlab
andylab
: Label the x-axis and y-axis, respectively.main
: Adds a title to the plot,grid()
: Adds grid lines to the plot,points()
: Adds points to the plot to highlight the data.legend()
: Adds a legend to the plot.
R program to Customize graph
R
# Creating x and y-values x <- 1:5 y <- x * x # Using plot function with additional settings plot (x, y, type = "b" , col = "blue" , pch = 16, lty = 2, main = "Quadratic Function" , xlab = "X-axis" , ylab = "Y-axis" ) # Add grid lines grid () # Add points to highlight data points (x, y, col = "red" , pch = 16) # Add a legend legend ( "topleft" , legend = "y = x^2" , col = "blue" , pch = 16, lty = 2) # Adding a title title (main = "Quadratic Function" , sub = "y = x^2" , col.main = "blue" , col.sub = "red" , font.main = 4, cex.main = 1.2, cex.sub = 0.8) |
Output:
In this code we creates a quadratic function plot with blue points connected by dashed lines. It includes a title, axis labels, grid lines, red-highlighted data points, and a legend indicating the equation 2y=x2. The main title and subtitle have custom colors and font styles for improved visualization.
Multiple Plots In R
R
# Create data for multiple plots x <- 1:5 y1 <- x * x y2 <- 2 * x y3 <- x^2 - 3 # Set up a 2x2 grid for plots par (mfrow = c (2, 2)) # Plot the first graph plot (x, y1, type = "b" , col = "blue" , pch = 16, main = "Plot 1" , xlab = "X-axis" , ylab = "Y-axis" ) # Plot the second graph plot (x, y2, type = "o" , col = "green" , pch = 17, main = "Plot 2" , xlab = "X-axis" , ylab = "Y-axis" ) # Plot the third graph plot (x, y3, type = "l" , col = "red" , lty = 2, main = "Plot 3" , xlab = "X-axis" , ylab = "Y-axis" ) # Reset the graphical parameters to default par (mfrow = c (1, 1)) |
Output:
par(mfrow = c(2, 2))
is like setting up a grid of 2 rows and 2 columns for your plots. This means we can create four plots, and they will be arranged in a 2×2 grid.
- Each time we use the
plot
function after setting up the grid, it adds a new plot to one of the grid positions. Each plot can have different data and visual styles. - This ensures that any future plots you make won’t be constrained to the grid; they’ll be displayed as standalone plots.
Overlaying Graphs using plot function
R
# Create data for multiple plots x <- 1:5 y1 <- x * x y2 <- 2 * x y3 <- x^2 - 3 # Plot the first graph plot (x, y1, type = "b" , col = "blue" , pch = 16, main = "Overlaying Graphs" , xlab = "X-axis" , ylab = "Y-axis" ) # Overlay the second graph points (x, y2, col = "green" , pch = 17) # Overlay the third graph lines (x, y3, col = "red" , lty = 2) # Add a legend legend ( "topleft" , legend = c ( "y = x^2" , "y = 2x" , "y = x^2 - 3" ), col = c ( "blue" , "green" , "red" ), pch = c (16, 17, NA ), lty = c (1, 1, 2)) |
Output:
In this example the plot
function is used to create the first graph. the points
function overlays points from the second graph on the existing plot.
The lines
function overlays a line from the third graph on the existing plot. legend
adds a legend to distinguish between different datasets.