Course

Additional

Find the Statistical Mode Write to a File Format Decimal Places

Data Frames

Convert a List to a Dataframe Create an Empty Dataframe Combine Two Dataframe into One Change Column Name of a Dataframe Extract Columns From a Dataframe Drop Columns in a Dataframe Reorder Columns in a Dataframe Split Dataframe Merge Multiple Dataframes Delete Rows From Dataframe Make a List of Dataframes

Introduction

"Hello World" Program Add Two Vectors Find Sum, Mean and Product of Vector in R Programming Take Input From User Generate Random Number from Standard Distributions Sample from a Population Find Minimum and Maximum Sort a Vector

Strings

Concatenate Two Strings Find the Length of a String Check if Characters are Present in a String Extract n Characters From a String Replace Characters in a String Compare two Strings Convert Factors to Characters Trim Leading and Trailing Whitespaces

Vectors

Concatenate a Vector of Strings Check if a Vector Contains the Given Element Count the Number of Elements in a Vector Find Index of an Element in a Vector Access Values in a Vector Add Leading Zeros to Vector

Decision and Loops

Find the Factorial of a Number R Multiplication Table Check Prime Number check Armstrong Number Print the Fibonacci Sequence Check for Leap Year Check if a Number is Odd or Even in R Programming Check if a Number is Positive, Negative or Zero Find the Sum of Natural Numbers

Functions

Convert Decimal into Binary using Recursion in R Find the Factorial of a Number Using Recursion Find the Factors of a Number Fibonacci Sequence Using Recursion in R Find H.C.F. or G.C.D.Find L.C.M.Make a Simple Calculator Sum of Natural Numbers Using Recursion

R Program to Sample from a Population

We generally require to sample data from a large population.

R has a function called sample() to do the same. We need to provide the population and the size we wish to sample.

Additionally, we can specify if we want to do sampling with replacement. By default it is done without replacement.

Example: Sample From a Population

Sample 2 items from x


              
> x
[1]  1  3  5  7  9 11 13 15 17

> # sample 2 items from x
> sample(x, 2)
[1] 13  9

If we don’t provide the size to sample, it defaults to the length of the population. This can be used to scramble x.

More examples to sample from a population.


              
> # sample with replacement
> sample(x, replace = TRUE)
[1] 15 17 13  9  5 15 11 15  1

> # if we simply pass in a positive number n, it will sample
> # from 1:n without replacement
> sample(10)
 [1]  2  4  7  9  1  3 10  5  8  6

An example to simulate a coin toss for 10 times.


              
> sample(c("H","T"),10, replace = TRUE)
 [1] "H" "H" "H" "T" "H" "T" "H" "H" "H" "T"