Lecture 4: Lists, Tuples and Strings

Based on the lecture and the readings (R&S Lists, Tuples & Strings) you should be able to:

• Understand how to index a list, tuple, or string

• Understand how to construct a list in a loop

• Explain the difference between list1 = list2 and list1 = list2[:]

Below, please find some practice problems for this topic. These problems should be completed by hand, that is, without the use of a computer.

1. What is the output of the following code fragmemt?

lst = ['a', 'b', 'c', 'd', 'e']

print(lst[0])
print(lst[1])
print(lst[-1])
print(lst[:4])

2. Write an expression that will extract the substring "bcd" from s:

s = 'abcde'

3. What will happen if I try to run the following code:

lst = [10, 20, 30]
lst[3]

4. What is the output of the following code fragment?

x = ['abcde', [1, 2, 3, 4], 8, 9, 100, 'hello']
y = x[0] + x[-1]
z = x[0][:2]
x.append(y)
x.append(z)
print(x)

5. What is the output of the following code fragment?

z = [0]*9
z[2] = 98
z[3] = 1
z[8] = 4

x = z[3]
z[x] = 3
z[z[8]] = 27

print(z)

6. What is the output of the following code fragment?

lst = []
for i in range(3,10):
    lst.append(i // 3)
print(lst)