Week 3 Refresher

Let’s refresh your memory!

Part 1: Variables and Types

Information

There are four basic variable types

1
2
3
4
x = 5     # int
x = 5.0   # float
x = "5"   # str
x = True  # bool

Practice time

For each item, write down on a sheet of paper the exact code, the result, and the type. As an example, I’ve written the first one on the white board.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
item1 = str(5.0)
item2 = "a" + "bunny"
item3 = 2*2
item4 = item2[1]
item5 = item2[:5]
item6 = item4 + item5
item7 = float(item1) * 3
item8 = int(item7)
item9 = item8 % 2
item10 = str(item9)

Part 2: String Practice

Information

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
#       012345678
name = "Bunnyface"
#       012345678
# these are all negative: (but there's not enough room for the "-" for all numbers
#      -987654321

# Indexing retrieves the letter at that spot!
name[0] #  is "B"
name[5] # is "f"
name[-1] # is "e"

# Slicing gets the range of letters
# It starts with the first number
# and it goes UP TO the second number
name[0:4]  # is "Bunn"

# Sometimes you have to use a number beyond the end of the string

name[5:9]  # is "face"

# you can use variables
index = 2
start = 4
stop = 7
name[index] # is "n"
name[start:stop] # is "yfa"

# you can also leave out the start of the stop, it assumes the beginning or end
name[:stop] # is "Bunnyfa"
name[start:] # is "yface"

Practice

For each of the following, write down the result!

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
#           01234567
original = "Penguins"
#           01234567

item1 = original[0]
item2 = original[4]
item3 = original[1:5]
item4 = item2 + item3
item5 = item3*2 + item1
item6 = original[-3]
item7 = original[:-1]

### what does i need to be to make item8 equal "g"?
# i = ?
item8 = original[i]