Bracket operator, non-negative index
LETTER = STRING[J]
if J is equal to or greater than
zero:
LETTER is the (J+1)-eth
letter of STRING
Example:
name = "Sandy"
firstLetter=name[0]
secondLetter=name[1]
lastLetter=name[4]
print firstLetter, secondLetter, lastLetter
prints:
S a y