How to customize the axis of a Bar Plot in R
Last Updated :
18 Jul, 2021
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:
