Question

Assignment 1 - IN PDF FORMAT Using R and Rstudio

Pick a database from: data()

Then preview the first 10 rows.

Print the number of rows and columns

- Print the names of the variables

If you have row names, print them - work with the values for a field in your dataset. You can do it by dataset[[xx]] operator with xx can be the index of the field or the nae of the field.

Now use dataset[xx] to get a slice of datframe instead of vector, e.g. df = mtcars[c(‘mpg’, ‘disp’)] - With two scalar arguments (rows,columns), the [] operator can select elements in the dataframe. Try this.

- Subset your data using rules similar to the lectures. For example part of the data that has a characteristics AND/OR another one, etc.

- Write a function that does an operation, for example averaging a property, on your dataset.

- Write a function that works on rows and adds a column to the dataset with the results for each row.

- Using the iris database, explain the following line of code:

data(iris) aggregate(iris["Petal.Length"], by = iris["Species"], FUN=median)

## Species Petal.Length

## 1 setosa 1.50

## 2 versicolor 4.35

## 3 virginica 5.55

Answer 1

IF YOU HAVE ANY DOUBTS COMMENT BELOW I WILL BE TTHERE TO HELP YOU..ALL THE BEST

CODE:

set.seed(1)
dataset <- data.frame(A = sample(c(NA, 1:100), 1000, rep = TRUE),
                      B = rnorm(1000))

> head(dataset)
   A           B
1 26  0.07730312
2 37 -0.29686864
3 57 -1.18324224
4 91  0.01129269
5 20  0.99160104
6 90  1.59396745

> nrow(dataset)
[1] 1000
> NROW(dataset)
[1] 1000

#1

rm(list = ls())

# 1.1 Modes and Classes
mylist <- list(a = c(1, 2, 3),
               b = c("cat", "dog", "duck"),
               d = factor("a", "b", "a"))
sapply(mylist, mode)
sapply(mylist, class)

# 1.2 Data Storage in R
x <- c(1, 2, 5, 10)
x
mode(x)
y <- c(1, 2, "cat", 3)
mode(y)
z <- c(5, TRUE, 3, 7)
mode(z)
all <- c(x, y, z)
all

x <- c(one = 1,
       two = 2,
       three = 3)
x
x <- c(1, 2, 3)
x
names(x) <- c('one', 'two', 'three')
x
str(x)
mode(x)
class(x)

nums <- 1:10
nums + 1
nums + c(1, 2)
nums + 1:2
nums + c(1, 2, 3)

rmat <- matrix(rnorm(15), 5, 3,
               dimnames = list(NULL, c('A', 'B', 'C'))
               )
rmat
rmat[, 'A']
as.matrix(rmat[, 'A'])

mylist <- list(c(1, 4, 6),
               "dog", 3, "cat", TRUE, 
               c(9, 10, 11)
               )
mylist
sapply(mylist, mode)
sapply(mylist, class)

mylist <- list(first = c(1, 3, 5),
               second = c('one', 'three', 'five'),
               third = 'end')
mylist
mylist['third']

mylist <- list(c(1, 3, 5),
               c('one', 'three', 'five'), 'end')
names(mylist) <- c('first', 'second', 'third')
mylist

# 1.3 Testing for Modes and Classes
# no code

# 1.4 Structure of R Objects

mylist <- list(a = c(1, 2, 3),
               b = c('cat', 'dog', 'duck'),
               d = factor('a', 'b', 'a')
               )

summary(mylist)
nestlist <- list(a = list(matrix(rnorm(10), 5, 2),
                          val = 3),
                 b = list(sample(letters, 10),
                          values = runif(5)),
                 c = list(list(1:10, 1:20), list(1:5, 1:10))
                 )

summary(nestlist)
str(nestlist)

list(1:4, 1:5)

# 1.5 Conversion of Lists

nums <- c(12, 10, 8, 12, 10, 12, 8, 10, 12, 8)
tt <- table(nums)
tt
names(tt)
sum(names(tt) * tt)
sum(as.numeric(names(tt)) * tt)

as.numeric("123")

x=c(1, 2, 3, 4, 5)
list(x)
as.list(x)

I HOPE YOU UNDERSTAND..

PLS RATE THUMBS UP..ITS HELPS ME ALOT..

THANK YOU...!!