Chapter Review Questions#

Note

Source: Adapted from the C# edition (for/reviewfor.rst). C#-specific format-string questions are replaced by f-string equivalents. Python-specific questions on range(), enumerate(), and list comprehensions are added.

Choosing the right loop.
1. When might you prefer a for loop over a while loop?
2. What do you gain by using for?
When might you prefer a while loop over a for loop?
When you have nested for loops and reach the bottom of the inner loop body, where does execution go next?
Write a range() expression that produces: 0, 1, 2, 3, 4.
Write a range() expression that produces: 3, 4, 5, 6, 7.
Write a range() expression that produces: 0, 3, 6, 9, 12.
Write a range() expression that produces: 10, 8, 6, 4, 2.
Rewrite the following without using +=:
```
total += score
```
Rewrite the following using a compound assignment operator so that big_name appears only once:
```
big_name = big_name * 2
```
What does enumerate() give you that a plain for item in seq: loop does not?

What is printed? Trace through by hand before running:

for i in range(1, 4):
    for j in range(i):
        print(j, end=" ")
    print()

What is printed?:

s = "abcde"
for i in range(0, len(s), 2):
    print(s[i])

Write a list comprehension that produces the cubes of 1 through 5: [1, 8, 27, 64, 125].

Write a list comprehension equivalent to:

result = []
for w in ["hello", "world", "python"]:
    if len(w) > 4:
        result.append(w.upper())

Two similar expressions.
1. What is the type and value of [n * 2 for n in range(5)]?
2. What is the type and value of (n * 2 for n in range(5))?
3. When would you prefer the second form?