May 12, 2021 R language tutorial
The histogram represents how often the values of variables are stored in the range. A histogram is similar to a bar chart, but the difference is that the values are grouped into consecutive ranges. E ach bar in the histogram represents the height of the number of values present in the range.
The R language uses the hist() function to create histograms. T his function uses vectors as inputs and uses some more parameters to draw histograms.
The basic syntax for creating histograms in the R language is -
hist(v,main,xlab,xlim,ylim,breaks,col,border)
The following is a description of the parameters used -
v is a vector that contains the values used in histograms.
Main represents the title of the chart.
Col is used to set the color of the bar.
Border is used to set the border color for each bar.
xlab is used to give a description of the x-axis.
xlim specifies the range of values on the x-axis.
ylim specifies the range of values on the y-axis.
Break is used to refer to the width of each bar.
Create a simple histogram using input vector, label, col, and boundary parameters.
The script given below creates and saves the histogram in the current R-language working directory.
# Create data for the graph. v <- c(9,13,21,8,36,22,12,41,31,33,19) # Give the chart file a name. png(file = "histogram.png") # Create the histogram. hist(v,xlab = "Weight",col = "yellow",border = "blue") # Save the file. dev.off()
When we execute the code above, it produces the following results -
To specify the range of values allowed on the X and Y axes, we can use the xlim and ylim parameters.
The width of each bar can be determined by using intervals.
# Create data for the graph. v <- c(9,13,21,8,36,22,12,41,31,33,19) # Give the chart file a name. png(file = "histogram_lim_breaks.png") # Create the histogram. hist(v,xlab = "Weight",col = "green",border = "red", xlim = c(0,40), ylim = c(0,5), breaks = 5) # Save the file. dev.off()
When we execute the code above, it produces the following results -