Histograms in R language

Histograms in detail

A histogram is a graphical representation of statistical data that groups data points into specified ranges. The rectangular bars in a histogram represent frequencies, with their heights proportional to the frequency of values in each range. Unlike bar graphs, histograms do not have gaps between bars.

Creating Histograms in R

Histograms in R can be created using the hist() function.

Syntax:

hist(v, main, xlab, xlim, ylim, breaks, col, border)

Parameters:

• v: Numeric values used to create the histogram.
• main: Title of the chart.
• col: Color of the bars.
• xlab: Label for the horizontal axis.
• border: Color of the bar borders.
• xlim: Range of values on the x-axis.
• ylim: Range of values on the y-axis.
• breaks: Defines the width of each bar.

Example 1: Creating a Simple Histogram

# Creating data for the graph
values <- c(10, 25, 15, 8, 20, 18, 30, 12, 22, 28, 35)

# Creating the histogram
hist(values, xlab = "Frequency of Items",
     col = "blue", border = "black")

Output:

Example 2: Setting X and Y Ranges

# Creating data for the graph
values <- c(10, 25, 15, 8, 20, 18, 30, 12, 22, 28, 35)

# Creating the histogram
hist(values, xlab = "Frequency of Items", col = "blue",
    border = "black", xlim = c(0, 40),
    ylim = c(0, 5), breaks = 5)

Output:

Example 3: Adding Labels Using text()

# Creating data for the graph
values <- c(10, 25, 15, 8, 20, 18, 30, 12, 22, 28, 35, 110, 50, 80, 95)

# Creating the histogram
hist_data <- hist(values, xlab = "Weight", ylab = "Frequency",
                  col = "purple", border = "black",
                  breaks = 5)

# Adding labels
text(hist_data$mids, hist_data$counts, labels = hist_data$counts,
     adj = c(0.5, -0.5))

Output:

Example 4: Histogram with Non-Uniform Width

# Creating data for the graph
values <- c(10, 25, 15, 8, 20, 18, 30, 12, 22, 28, 35, 110, 50, 80, 95)

# Creating the histogram
hist(values, xlab = "Weight", ylab = "Frequency",
     xlim = c(10, 120),
    col = "purple", border = "black",
    breaks = c(5, 55, 60, 70, 75, 80, 100, 140))

Output: