This can be done by setting the levels of the variable in the order we want.Example> data data ggplot(data, aes(x = Class)) + geom_bar()Setting the levels in increasing order> data

Reordering of columns can be done by using square brackets.Example> df = data.frame(matrix(rnorm(20), nrow=5)) > df       X1       X2       X3       X4 1 -0.3637644 2.0770246 0.48763128 -0.09019256 2 -3.1758515 2.3173075 0.86846761 0.38396459 3 1.1844641 0.3412267 1.90986295 -1.03493074 4 -0.5953466 1.7211738 ... Read More

There are three ways to find the index of an element in a vector.Example> x x [1] 8 10 9 6 2 1 4 7 5 3Using which> which(x == 6)[[1]] [1] 4Here we found the index of 6 in vector x.Using match> match(c(4, 8), x) [1] 7 1Here ... Read More

This can be done simply by using sample function.Example> df = data.frame(matrix(rnorm(20), nrow=5)) > df X1 X2 X3 X4 1 -0.3277833 -0.1810403 ... Read More

We can do this by defining the newname as shown below −> Samp Samp sample.1.100..10. 1 47 2 63 3 57 4 16 5 53 6 7 7 54 8 2 9 13 10 14 > colnames(Samp) Samp Sampled Values 1 47 2 63 3 57 4 16 5 53 6 7 7 54 8 2 9 13 10 14 Since we only have one column in the data frame, so it is sufficient to use the object name.

The easiest way to add zeros before numbers is by using paste0 functionExample> ID Gender Lens data data ID Gender Lens 1 25499 1 0.8 2 25500 2 1.2 3 25501 2 1.0 4 25502 1 2.0 5 25503 2 1.8 6 25504 1 1.4Let’s say we want to add 00 before every ID.It can be done by using paste0 function as follows −> IDs newdata newdata IDs Gender Lens 1 0025499 1 0.8 2 0025500 2 1.2 3 0025501 2 1.0 4 0025502 1 2.0 5 0025503 2 1.8 6 0025504 1 1.4

We can do this by using aggregate function or with the help tapplyExample> x x Category Frequency 1 Graduation 12 2 Graduation 19 3 Post-Graduation 15 4 Graduation 20 5 PhD 25 6 Post-Graduation 13 7 PhD 14Using aggregate> aggregate(x$Frequency, by=list(Group=x$Category), FUN=sum) Group x 1 ... Read More

Example> x y z df library(dplyr) > df %>% select(y, z) y z 1 1.486720e-06 7.888609e-31 2 1.338302e-04 7.888609e-29 3 4.431848e-03 3.904861e-27 4 5.399097e-02 1.275588e-25 5 2.419707e-01 3.093301e-24 6 3.989423e-01 5.939138e-23 7 2.419707e-01 9.403635e-22 8 5.399097e-02 1.262774e-20 9 4.431848e-03 1.467975e-19 10 1.338302e-04 1.500596e-18 11 1.486720e-06 1.365543e-17 12 ... Read More

Concatenation can be done by using paste function in R.Example> paste("I", "Love", "R", sep=" ") [1] "I Love R"If we want to specify characters between words then it can be done by using collapse argument as follows −> x x [1] "I" "Love" "R" > paste(x, collapse="-") [1] "I-Love-R"

Just like mean and median there is no in-built function in R to find the mode.We can make use of the following user created function for this purpose> Modes