How to change legend values in a bar plot created by using ggplot2 in R?By default, the legend values are taken as the different levels of the categorical variable for which a bar plot is created using ggplot2 package and if we want to change those values then scale_color_manual function of the ggplot2 package can be used where we need to pass the values for color and labels for legend values.ExampleConsider the below data frame:Live Demo> set.seed(1214) > x1 y1 df1 df1Output x1 y1 1 B 4 2 B 5 3 C 5 ... Read More

One of the mostly used time measurement function in R is microbenchmark function of microbenchmark package. We can pass the function to create the plot inside microbenchmark function and this will result in the processing time for each of the plots then a comparison can be done for the difference.Example1Loading microbenchmark package:> library(microbenchmark)Finding the plot generation time:> x1 x2 x3 X XUnit: milliseconds expr min lq mean median uq max neval plot(x1) 12.7488 14.88815 15.65040 15.2515 15.90765 23.9348 100 plot(x2) 20.9810 21.67780 23.92976 22.2116 23.29665 137.2474 100 plot(x3) 93.6965 95.03440 96.67086 95.6717 97.12290 125.3670 100Plots:Example> plot(x1)Output:Example> plot(x2)Output:Example> plot(x3)Output:

In base R, we can save a plot as a png and pass the resolution in the same stage. The procedure to do this is creating the png image with resolution with res argument then creating the plot and using dev.off() to create the file. Check out the below examples to understand how it works.Example1Live Demo> png(file="example1.png",res=100) > plot(1:10) > dev.off()Output:Example2Live Demo> png(file="example2.png",res=200) > plot(1:10) > dev.off()Output

The cex argument is used to increase or decrease the point size in a point chart created in base R. If we want to create a point chart with points of size in increment manner then we can pass a vector of the same size as the vector for which we want to create the point chart. For example, if we have a vector x that contains 10 elements then cex will be set as cex=1:10.Example1Live Demo> x plot(x, cex=1:10, xlim=c(1, 12), ylim=c(-2, 12))Output:ExampleLet’s have a look at another example:Live Demo> y plot(y, cex=1:10, xlim=c(1, 12), ylim=c(-1, 12))Output:Read More

How to create a point chart in R with alternative points having different shape?The pch argument is used to create different points in a base R chart and if we want to have alternative points of different shape then we can use rep function with pch argument but we need to use it for the exact length of the vector. For example, if we want to create a point chart of a vector that contains 10 values having different shapes of alternate points then we can use pch=rep(1:2, 5)).Example1Live Demo> x plot(x, pch=rep(1:2, 5))Output:ExampleLet’s have a look at another example:Live ... Read More

While doing the analysis we might know the variation in an independent variable or we might want to understand how other independent variables behave if we fix a certain variable. Therefore, we can fix the coefficient of an independent variable while creating the model and this can be done by using offset function with the coefficient of the variable for which we want to fix the value of the coefficient.ExampleConsider the below data frame:Live Demo> set.seed(854) > x1 x2 y1 df1 df1Output x1 x2 ... Read More

If we want to have gaps on Y-axis scale in a barplot then it cannot be done in base R. For this purpose, we can make use of gap.barplot function of plotrix package. The gap.barplot function is very handy, we just need to pass the vector for which we want to create the barplot and the gap values simply by using gap argument.Loading plotrix package:> library(plotrix)Example1Live Demo> x xOutput[1] 2 6 5 4 7 2 5 2 5 2 8 6 8 13 3 5 7 7 5 6> gap.barplot(x, gap=c(2, 4)) ylim 0 11Warning message:In gap.barplot(x, gap = c(2, ... Read More

First thing we need to understand is diagonal elements are useful only if we have a square matrix, otherwise it would not make sense to set diagonal elements, this is known to almost all mathematicians but some freshman might get confused because we can create diagonal in a non-square matrix which should not be called a diagonal. In R, we can set the diagonal elements of a matrix to 1 by using diag function.Example1Live Demo> M1 M1Output     [, 1] [, 2] [, 3] [, 4] [, 5] [1, ]   1    6   11   16   21 ... Read More

A boxplot in base R already consists three horizontal lines that represents minimum, median, and the maximum but we might to create an extra horizontal to showcase some threshold value. For example, we might to create a horizontal line at 2 to understand the variation in values that are greater than say 2. This can be done very easily by using abline function after creating the boxplot.Example1Live Demo> x boxplot(x) > abline(h=1)Output:Example2Live Demo> y boxplot(y) > abline(h=15)Output:Example3Live Demo> z boxplot(z) > abline(h=3)Output:

How to create normal quantile-quantile plot for a logarithmic model in R?A logarithmic model is the type of model in which we take the log of the dependent variable and then create the linear model in R. If we want to create the normal quantile-quantile plot for a logarithmic model then plot function can be used with the model object name and which = 2 argument must be introduced to get the desired plot.Example1Live Demo> x1 x1Output[1]  4.735737 3.631521 5.522580 5.538314 5.580952 4.341072 4.736899 2.455681 [9]  4.042295 5.534034 4.717607 6.146558 4.466849 5.444437 5.390151 4.491595 [17] 4.227620 4.223362 5.452378 5.690660 5.321716 ... Read More