How to plot Histogram in R?

vishrut-singhal · 21 May 2021 15:47

R Histogram

A histogram is a type of bar chart which shows the frequency of the number of values which are compared with a set of values ranges. The histogram is used for the distribution, whereas a bar chart is used for comparing different entities. In the histogram, each bar represents the height of the number of values present in the given range.

For creating a histogram, R provides hist() function, which takes a vector as an input and uses more parameters to add more functionality. There is the following syntax of hist() function:

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

Here,

S.No	Parameter	Description
1.	v	It is a vector that contains numeric values.
2.	main	It indicates the title of the chart.
3.	col	It is used to set the color of the bars.
4.	border	It is used to set the border color of each bar.
5.	xlab	It is used to describe the x-axis.
6.	ylab	It is used to describe the y-axis.
7.	xlim	It is used to specify the range of values on the x-axis.
8.	ylim	It is used to specify the range of values on the y-axis.
9.	breaks	It is used to mention the width of each bar.

Let?s see an example in which we create a simple histogram with the help of required parameters like v, main, col, etc.

Example

# Creating data for the graph.  
v <-  c(12,24,16,38,21,13,55,17,39,10,60)  
  
# Giving a name to the chart file.  
png(file = "histogram_chart.png")  
  
# Creating the histogram.  
hist(v,xlab = "Weight",ylab="Frequency",col = "green",border = "red")  
  
# Saving the file.  
dev.off()

Output:

Let?s see some more examples in which we have used different parameters of hist() function to add more functionality or to create a more attractive chart.

Example: Use of xlim & ylim parameter

# Creating data for the graph.  
v <-  c(12,24,16,38,21,13,55,17,39,10,60)  
  
# Giving a name to the chart file.  
png(file = "histogram_chart_lim.png")  
  
# Creating the histogram.  
hist(v,xlab = "Weight",ylab="Frequency",col = "green",border = "red",xlim = c(0,40), ylim = c(0,3), breaks = 5)  
  
# Saving the file.  
dev.off()

Output:

Example: Finding return value of hist()

# Creating data for the graph.  
v <-  c(12,24,16,38,21,13,55,17,39,10,60)  
  
# Giving a name to the chart file.  
png(file = "histogram_chart_lim.png")  
# Creating the histogram.  
m<-hist(v)  
m

Output:

Example: Using histogram return values for labels using text()

# Creating data for the graph.  
v <-  c(12,24,16,38,21,13,55,17,39,10,60,120,40,70,90)  
# Giving a name to the chart file.  
png(file = "histogram_return.png")  
  
# Creating the histogram.  
m<-hist(v,xlab = "Weight",ylab="Frequency",col = "darkmagenta",border = "pink", breaks = 5)  
#Setting labels  
text(m$mids,m$counts,labels=m$counts, adj=c(0.5, -0.5))  
# Saving the file.  
dev.off()

Output:

Example: Histogram using non-uniform width

    # Creating data for the graph.  
    v <-  c(12,24,16,38,21,13,55,17,39,10,60,120,40,70,90)  
    # Giving a name to the chart file.  
    png(file = "histogram_non_uniform.png")  
    # Creating the histogram.  
    hist(v,xlab = "Weight",ylab="Frequency",xlim=c(50,100),col = "darkmagenta",border = "pink", breaks=c(10,55,60,70,75,80,100,120))  
    # Saving the file.  
    dev.off()

Output: