Lezione 1

Question 1

6 main rules

Answer 1

rm(list=ls())

Use # to comment

Set directory properly and check which files are available with function dir()

Before reading csv files check if data are separated by commas

Use str() function

use dots for decimal numbers instead of commas

Question 2

How do I create new objects?

Answer 2

An = sign is always necessary to create new objects

I can print them on the console by just typing them in the script

Question 3

setwd() and get()

Answer 3

Set and print the active folder on the console.

Question 4

read.csv

Answer 4

Comma Separated Values

Question 5

head(data)

Answer 5

Print on the console the first rows and columns of a dataframe

Question 6

Environment

Answer 6

Left Side Toggle: see dataframe structure (str())

Right Side Tab: open new script with full table of data

Delete an object: grid mode=> broom emoji

Question 7

Delete dataframe vector

Answer 7

dati_pinguini$X = NULL

Question 8

Convert Vector from chr to num

Answer 8

dati$X = factor(dati$X)

Question 9

Create vectors (2 ways)

Answer 9

v1=c(1,2,3,4)
v3 = seq(1,10, by = 0.1)

Question 10

Second v1 element

Second and fourth v1 element

From the first to the third v1 element

Answer 10

v1[2]
v1[c(2,4)]
v1[1:3]

Question 11

Calculate Quantile

Answer 11

quantile(dati$peso, c(0.25, 0.75))

Question 12

Dispersion Indices

Answer 12

var(dati$peso)
sd(dati$peso)
IQR(dati$peso)

Question 13

summary(data)

Answer 13

Prints out the main position indices on the console