R functions

to create a boxplot

boxplot(data)

to create a Normal Quantile-Quantile (“QQ”) plot

qqnorm(data)

to create a histogram

hist(data)

to create a plot graph

plot(data)

to display the first few rows of R data

head(data)

to display the last few rows of R data

tail(data)

to return the dimensions of a data frame

dim(data)

to determine the number of elements in a dataset

length(data)

to generate all possible ways to choose a specific number of items from a larger set, where the order of selection does not matter.

combinations()

to create a subset of data from a larger dataset

sample()

to arrange data into a specific order

sort()

to provide a quick overview of the dataset

summary()

to install packages

install.packages(“gtools”)

to see the package library for R

library(gtools)

to see installed packages in R

installed.packages()

to determine the class or type of an R object

class(df)

to determine the data type or class of a specific column within a data frame

class(df$colname)

similar to a pivot table in excel, used to apply a function (FUN=) to subsets of data within a data frame

aggregate()

part of the “apply()” family of functions and is used to apply a specified function (FUN=) to each element of a list or vector, lists columns vertically

lapply()

part of the “apply()” family of functions and is used to apply a specified function (FUN=) to each element of a list or vector, lists columns horizontally

sapply()

what does “df” stand for

“data frame”

converts various R objects into a data frame structure

as.data.frame()

calculates the sum of values in each row of a data frame. 

rowsums(df)

calculates the sum of values in each column of a data frame

colsums(df)

used to calculate the mean of each row in a data frame

rowMean(df)

used to calculate the mean of each column in a data frame

colMean(df)

used to access and modify the column names of data frames

colnames()

sorts data from low to high

order()

3 ways used to create calculated columns

• df$new.col.name<-column1+column2

• df$new.col.name<-sum(col1+col2)/2

• df$new.col.name<-mean(col1+col2)

used to select subsets of data from data frames

subset()

element used to make variables

<-

element used to combine elements

c()

element used to make comments

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