R Histogram

A histogram is a graphical display of data using bars of different heights.

Histogram is used to summarize discrete or continuous data that are measured on an interval scale.

Create Histogram in R

In R, we use the hist() function to create Histograms. For example,

temperatures <- c(67 ,72 ,74 ,62 ,76 ,66 ,65 ,59 ,61 ,69 )

# histogram of temperatures vector
result <- hist(temperatures)

print(result)

Output

In the above example, we have used the hist() function to create a histogram of the temperatures vector.

The histogram we have created above is plain and simple, we can add so many things to the Histogram.

Add Title and Label to a Histogram in R

To add a title and a label to our Histogram in R, we pass the main and the xlab parameter respectively inside the hist() function. For example,

temperatures <- c(67 ,72 ,74 ,62 ,76 ,66 ,65 ,59 ,61 ,69 )

# histogram of temperatures vector
result <- hist(temperatures,
  main = "Histogram of Temperature",
  xlab = "Temperature in degrees Fahrenheit" 
)

print(result)

Output

In the above figure, we can see that we have added a title and a label to the Histogram of the temperatures vector.

hist(temperatures, 
  main = "Maximum Temperatures in a Week",
  xlab = "Temperature in degrees Fahrenheit")

Here,

• main - adds the title "Maximum Temperatures in a Week"
• xlab - adds the label "Temperature in degrees Fahrenheit"

Change Bar Color of Histogram in R

In R, we pass the col parameter inside hist() to change the color of bars. For example,

temperatures <- c(67 ,72 ,74 ,62 ,76 ,66 ,65 ,59 ,61 ,69 )

# histogram of temperatures vector
result <- hist(temperatures,
  main = "Histogram of Temperature",
  xlab = "Temperature in degrees Fahrenheit",
  col = "red")

print(result)

Output

In the above example, we have used the col parameter inside barplot() to change the color of bars.

result <- hist(temperatures, 
  ...
  col = "red"
)

Here, col = "red" changes the color of bars to red.

Range of Axes in R

To provide a range of the axes in R, we pass the xlab and the ylab parameter inside hist(). For example,

temperatures <- c(67 ,72 ,74 ,62 ,76 ,66 ,65 ,59 ,61 ,69 )

# histogram of temperatures vector
result <- hist(temperatures,
  main = "Histogram of Temperature",
  xlab = "Temperature in degrees Fahrenheit",
  col = "red",
  xlim = c(50,100),
  ylim = c(0, 5))

print(result)

Output

In the above example, we have used the xlim and the ylim parameter inside hist() to provide a range of x-axis and y-axis respectively.

result <- hist(temperatures, 
  ...
  xlim = c(50,100),
  ylim = c(0, 5))
)

Here,

• x-axis ranges from 50 to 100
• y-axis ranges from 0 to 5