How to customize the axis of a Bar Plot in R

Barplots in R programming language can be created using the barplot() method. It takes as input a matrix or vector of values. The bar heights are equivalent to the values contained in the vector. 

Syntax: barplot(H, xlab, ylab, main, names.arg, col)

Labeling the X-axis of the bar plot

The names.args attribute in the barplot() method can be used to assign names to the x-axis labels. Numeric or character labels can be assigned which are plotted alternatively on the display window. 

Example: Labeling the X-axis of the barplot

R

# creating a data frame
data_frame <- data.frame(col1 = 1:20,
                         col2 = 1:20,
                         col3 = 1)

# printing the data frame
print ("Original DataFrame")
print (data_frame)

# plotting a barplot
barplot(data_frame$col2, names.arg = data_frame$col1)

Output

Setting the Y-axis limit of the bar plot

The ylim parameter of the barplot() method can be used to set limits to portray on the display window. It contains a vector containing lower and higher limit. 

Example: Setting the Y-axis limit of the bar plot

R

# creating a data frame
data_frame <- data.frame(col1 = 1:20,
                         col2 = 1:20,
                         col3 = 1)

# printing the data frame
print ("Original DataFrame")
print (data_frame)

# plotting a barplot
barplot(data_frame$col2, names.arg = data_frame$col1 , ylim= c(0,50) )

Output

Setting the X-axis limit of the bar plot

The xlim parameter of the barplot() method can be used to set limits to portray on the display window. It contains a vector containing lower and higher limit. 

Example: Setting the X-axis limit

R

# creating a data frame
data_frame <- data.frame(col1 = 1:20,
                         col2 = 1:20,
                         col3 = 1)

# printing the data frame
print ("Original DataFrame")
print (data_frame)

# plotting a barplot
barplot(data_frame$col2, names.arg = data_frame$col1 , xlim= c(0,50) )

Output

Plotting logarithmic Y-axis

The log parameter can be set to display the axis and its corresponding values on the logarithmic scale. Setting the log value equivalent to character string y displays the modifications on the y axis. 

Example: Plotting logarithmic Y-axis

R

# creating a data frame
data_frame <- data.frame(col1 = 1:20,
                         col2 = 1:20,
                         col3 = 1)

# printing the data frame
print ("Original DataFrame")
print (data_frame)

# plotting a barplot
barplot(data_frame$col2, names.arg = data_frame$col1 , log = "y" )

Output

Plotting logarithmic X-axis

The log parameter can be set to display the axis and its corresponding values on the logarithmic scale. Setting the log value equivalent to character string x displays the modifications on the x-axis. 

Example: Plotting logarithmic X-axis

R

# creating a data frame
data_frame <- data.frame(col1 = 1:20,
                         col2 = 1:20,
                         col3 = 1)

# printing the data frame
print ("Original DataFrame")
print (data_frame)

# plotting a barplot
barplot(data_frame$col2, names.arg = data_frame$col1 , log = "x" )

Output

Renaming the group labels

The names.arg attribute can be renamed to assign a new set of labels to the x-axis arguments.

Example: Renaming the group labels

R

# creating a data frame
data_frame <- data.frame(col1 = 1:5,
                         col2 = 5:9,
                         col3 = 1)

# printing the data frame
print ("Original DataFrame")
print (data_frame)

# plotting a barplot
barplot(data_frame$col2, names.arg =c(
  "Grp1","Grp2","Grp3","Grp4","Grp5"))

Output

Adding label orientation

The orientation of the axis labels can be changed using the las attribute. The following specification symbols are used to specify the orientation : 

0: always parallel to the axis

1: always horizontal

2: always perpendicular to the axis

3: always vertical.

Example: Adding label orientation

R

# creating a data frame
data_frame <- data.frame(col1 = 1:20,
                         col2 = 1:20,
                         col3 = 1)

# printing the data frame
print ("Original DataFrame")
print (data_frame)

# plotting a barplot
barplot(data_frame$col2, names.arg = data_frame$col1 , las=3)

Output

Adding axis labels

The xlab and ylab attributes contain character strings, which assign the respective names to the axes of the bar plots. 

Example: Adding axis labels

R

# creating a data frame
data_frame <- data.frame(col1 = 1:20,
                         col2 = 1:20,
                         col3 = 1)

# printing the data frame
print ("Original DataFrame")
print (data_frame)

# plotting a barplot
barplot(data_frame$col2, names.arg = data_frame$col1 ,
        xlab = "Integers", ylab = "Numbers")

Output: