practice-problems.md

Practice problems

Jump start: Lesson 9

Overview

Complete each section by hand, then check your answers using irb

Variables and assignment practice

x = 5
# what value does x now hold?

z = "Hello"
# what value does z now hold?

a = 5
b = 3.2
c = a + b
# what values does c now hold?

var1 = "lawl"
var2 = "brb"
# what value does var2 now hold?

e = 6 + 3
# what values does e now hold?

f = 3.5
f = f + 2
# what value does f now hold?

poodle = 4
pitbull = 3
# what value does boxer now hold?

h = 5
h = h + h
# what values does h now hold?

j = 1
k = 2
m = 3
n = j + k + m
# what value does n now hold?

p = "moo"
q = "quack"
p  = q
# what value does p now hold?

r = "moo"
s = "quack"
t = "woof"
r = t
# what value does r now hold?

u = 5
u = u * 2
u = u * 2
u = u * 2
# what value does u now hold?

v = "b"
z = "a"
# what value does v now hold?


aa = 3234
bb = 2398
cc = 0
dd = (aa + bb) / cc
# what value does d now hold?

yy = 7
zz = yy % 2
# what value does zz now hold?

ee = 12
ff = ee % 4
# what value does ff now hold?


zz = 17
hh = zz % 3
# what value does hh now hold?

Operators practice

Consider the following variable assignments and then fill in the tables

d = 10
e = 5.0
f = 2
g = 11.0
h = 3
i = 1.5

Operation	Result	Data type of result
d + e
f + h
g + h
d - f
g - e
(h + i) - f
(d - f) + e
d * f
g * i
f * g
d / f
d / e
e / f
(g * f) / f
(d / f) * e
21 / 5
14 / 5
10 % 3
20 % 2
4 % 5
8 % 1

String practice

Determine the output of slice on your own and then check your answer using irb

# problem 1
my_string = "I love Seattle"
my_string.slice(7) 

# problem 2
my_string = "I love Seattle"
my_string.slice(2, 4)

# problem 3
my_string = "I love Seattle"
my_string.slice("Seattle")

# problem 4
my_string = "Ada"
my_string + " Lovelace"

# problem 5
my_string = "Ada"
my_string << " codes" << " it!"

# problem 6
my_string = "Ada"
my_string.concat(" likes to code").slice(4...9)

# problem 7
my_string = "Hello world"
"Goodbye " + my_string.slice(6, 5) << "!"

# problem 8
my_string = "Hello world!"
my_string.slice(0...5).concat(", goodbye!")

# problem 9
my_string = "Hello world!"
my_string.slice(0) << "i" + "!"

# problem 10
my_string = "I love ruby"
my_string.slice(7, 4).concat(my_string.slice(2...6)) + my_string.slice(0)

# problem 11
my_string = "I love ruby"
"R".concat(my_string.slice(8, 3) + " rocks!")

# problem 12
my_string = "I love ruby"
my_string.slice(2, 4) << my_string.slice(7...11).concat(my_string.slice(2...6))