Commit ee61bb16 authored by Weigert, Andreas's avatar Weigert, Andreas
Browse files

R Intro 1 solution added

parent 3e982601
---
title: 'Tutorial 1: R Introduction 1'
output: html_notebook
editor_options:
chunk_output_type: inline
---
This file is part of the lecture Business Intelligence & Analytics (EESYS-BIA-M), Information Systems and Energy Efficient Systems, University of Bamberg.
```{r Exercise: Mathematical calculations}
# Exercise 1
2 + 3*5^2
# Exercise 2
2^3^5
# Exercise 3
1.4e-2
# Exercise 4
1.4*exp(-2)
# Exercise 5
3*exp(1)^5 + 2
# Exercise 6
log2(33554432)
# Exercise 7
sin(pi/2)
```
```{r Exercise: Objects and assignements}
# Exercise 8
text <- c("a", "b")
text
# Exercise 9
row <- c(3, 7, 11, 15)
row
# Alternative:
row <- seq(from=3, to=15, by = 4)
row
# Exercise 10
u <- 1:10
u
# Exercise 11
x <- sample(1:99, 10)
x
```
```{r Exercise: Working with vectors}
# Exercise 12
x[1:3]
# Exercise 13
sort(x)
# Exercise 14
order(x)
# Exercise 15
x[order(x)]
# Exercise 16
x[x%%2==0]
# Exercise 17
v <- x^2
# Exercise 18
u <- u + 1
# Exercise 19
v/x
# Exercise 20
sqrt(v)
# Exercise 21
x + 0:1
```
```{r Exercise: Working with matrices}
# Exercise 22
matrix(0,nrow=2,ncol=2)
# Exercise 23
matrix(x,nrow=2)
# Exercise 24
A <- matrix(x,nrow=2)
# Exercise 25
A[1,]
# Exercise 26
sum(A[,-2])
```
```{r Exercise: Working with lists}
# Exercise 27
list_data <- list(text, u, x, A)
# Exercise 28
list_data[[2]]
# Exercise 29
list_data[[2]][3]
# Exercise 30
names(list_data) <- c("text", "u", "x", "A")
# Exercise 31
list_data
# Exercise 32
list_data$A
```
```{r Exercise: Working with data frames}
# For Exercise 33
ID <- c(876, 563, 345, 939)
Name <- as.character(c("Michael", "Susan", "Hans", "Björn"))
Age <- c(29,23,56,35)
Nationality <- as.factor(c("DE","US","DE","SE"))
# Exercise 33
students <- data.frame(ID=c(876, 563, 345, 939),
Name=as.character(c("Michael", "Susan", "Hans", "Björn")),
Age=c(29,23,56,35),
Nationality=as.factor(c("DE","US","DE","SE")))
# Long command: If you do not use proper datatypes and enhance the data.frame command by "stringsAsFactors = F", data types might not be correct.
students <- data.frame(ID=as.numeric(876, 563, 345, 939),
Name=as.character(c("Michael", "Susan", "Hans", "Björn")),
Age=as.numeric(c(29,23,56,35)),
Nationality=as.factor(c("DE","US","DE","SE")),
stringsAsFactors = F)
# Exercise 34
View(students)
# Exercise 35
students[3,2]
# Exercise 36
students$Age
# Exercise 37
students[students$Age < 30,"Name"] # colum name as identifier
students[students$Age < 30,2] # column index as identifier
students[students$Age < 30,]$Name # get a data.frame and then select the variable by $ operator
```
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