## 1.1 ##
# 1
setwd("D:/federico_sucunza/trabalhos/mestrado/disciplinas/USP/scripts")
# 2
nao
load("letras.rdata")

## 1.2 ##
# 1
rm(list=ls())
# 2
q()n

## 1.3 ##
# 1
letters
LETTERS
# 2
str(letters)
str(LETTERS)
# 3
letters.f <- factor(letters)
LETTERS.f <- factor(LETTERS)