# CS 1358 Introduction to Programming in Python SC5
###### tags: `pythonSC`
# Definitions and Short Answers - functions
1. What is the data type of (1, 2, 3)?
> tuple
2. If s = 'ABCDE', what is the value of
```python
s[0]
s[1]
s[-1]
s[1:4]
s[-5:-2]
s[:2]
s[-3:]
s[:]
s[0:0]
s[1:4:2]
s[-1:0:-1]
```
```python
'A'
'B'
'E'
'BCD'
'ABC'
'AB'
'CDE'
'ABCDE'
''
'BD'
'EDCB'
```
2. If S = ['h', 'e', 'l', 'l', 'o'], what is the value of S after executing the statement S[1:2] = ['a']?
```python
['h', 'a', 'l', 'o']
```
3. If T = ('h', 'e', 'l', 'l', 'o'), which of the following is allowed or not allowed and why?
```python
T[3] = 'z' #not allowed, tuple is immutable
T = ('w', 'o', 'r', 'l', 'd')
T = T[2:-1]
```
4. What is the value of
```python
list('apple')
tuple('apple')
set('apple')
```
```python
['a', 'p', 'p', 'l', 'e']
('a', 'p', 'p', 'l', 'e')
{'p', 'e', 'l', 'a'}
```
5. What is the value of
```python
str(['a', 'p', 'p', 'l', 'e'])
str(('a', 'p', 'p', 'l', 'e'))
str({'a', 'p', 'p', 'l', 'e'})
```
```python
"['a', 'p', 'p', 'l', 'e']"
"('a', 'p', 'p', 'l', 'e')"
"{'p', 'e', 'l', 'a'}"
```
6. What is the value of
```python
list(('a', 'p', 'p', 'l', 'e'))
tuple(['a', 'p', 'p', 'l', 'e'])
set(['a', 'p', 'p', 'l', 'e'])
```
```python
['a', 'p', 'p', 'l', 'e']
('a', 'p', 'p', 'l', 'e')
{'p', 'e', 'l', 'a'}
```
7. What is the result of
```python
'Apple' < 'apple' #True
'Apple' <= 'apple' #True
'Apple' == 'apple' #False
'Apple' >= 'apple' #False
'Apple' > 'apple' #False
'Apple' != 'apple' #True
```
8. What is the result of
```python
'Apple' < 'adventure' #True
'apple' < 'adventure' #False
'apple' < 'Adventure' #False
'apple' < 'bee' #True
'apple' < 'Bee' #False
'Apple' < 'bee' #True
'Apple' < 'Bee' #True
```
10. What is the result of
```python
('apple', 0) < ('apple', 2) #True
('apple', 0, 3) < ('apple', 1) #True
['apple', 2, 2] < ['apple', 2, 1, 5] #False
['apple', 3] < ['oranges', 0] #True
```
11. What is the result of
```python
's' in 'school' #True
'hoo' in 'school' #True
'S' in 'school' #True
'ol' in 'school' #False
'k' not in 'school' #True
's' not in 'School' #True
```
12. What is the result of
```python
's' in ['s', 'c', 'h', 'o', 'o', 'l'] #True
['s'] in ['s', 'c', 'h', 'o', 'o', 'l'] #False
['s'] in [['s'], ['c'], ['h'], ['o'], ['o'], ['l']] #True
'hoo' in ['s', 'c', 'h', 'o', 'o', 'l'] #False
['h', 'o', 'o'] in ['s', 'c', 'h', 'o', 'o', 'l'] #False
('h', 'o', 'o') in ['s', 'c', ('h', 'o', 'o'), 'l'] #True
('h', 'o', 'o') not in ('s', 'c', ('h', 'o', 'o'), 'l') #False
'ol' in ['s', 'c', 'h', 'o', 'ol'] #True
's' in ['S', 'c', 'h', 'o', 'o', 'l'] #False
```
13. What is the result of
```python
'sch' + 'ool'
[1, 2, 3] + [4, 5, 6]
(1, 2, 3) + (4, 5, 6)
```
```python
'school'
[1, 2, 3, 4, 5, 6]
(1, 2, 3, 4, 5, 6)
```
14. What is the result of
```python
'sch' + 'o' * 10 + 'l'
'do' * 5
['s'] + ['o'] * 5 + ['l']
```
```python
'schooooooooool'
'dododododo'
['s', 'o', 'o', 'o', 'o', 'o', 'l']
```
15. How do you express a tuple literal of a single element? For example, how do you write a tuple literal that has the same value as tuple([1])?
> (1, )
16. Suppose you have x = 1, 2, 3
What is the value of type(x)?
> tuple
17. Suppose you have L = ['f', 'r', 'o', 'g']
What is the new value of L after executing each of the following statements in order?
```python
L.append('s')
L.extend(['p', 'o', 'n', 'd'])
L.insert(4, ' ')
L.reverse()
L.sort()
L.remove('o')
L.pop()
L.pop(0)
L.clear()
L.append('z')
```
```python
['f', 'r', 'o', 'g', 's']
['f', 'r', 'o', 'g', 's', 'p', 'o', 'n', 'd']
['f', 'r', 'o', 'g', ' ', 's', 'p', 'o', 'n', 'd']
['d', 'n', 'o', 'p', 's', ' ', 'g', 'o', 'r', 'f']
[' ', 'd', 'f', 'g', 'n', 'o', 'o', 'p', 'r', 's']
[' ', 'd', 'f', 'g', 'n', 'o', 'p', 'r', 's']
's'
' '
[]
['z']
```
18. If T = (1, 3, 5, 7, 9, 11), Can you call del(T[1])? why or why not? Can you call del(T)? What is the effect?
> no, T is tuple, and tuple is immutable.
> yes, del T
19. Suppose L = list('hello') and separately M = list('hello'). After executing
```python
L.reverse()
M = M[::-1]
```
is L == M evaluate to True or False?
> True
What is the difference between these two ways of reversing elements in a list?
>One is mutation , another is immutation.
20. if T = tuple('hello'), are the following statements allowed in Python? Why or why not?
```python
T.reverse() #not allowed, tuple is immutable
T = T[::-1]
```
21. What is a stack as a data structure? What is another name (4-letter initialism) for a stack? How can a stack be implemented using a list? Show how push and pop can be accomplished by calling list methods.
>Yes, FIFO
```python
L.append() #push
L.pop() #pop
```
22. What is a queue as a data structure? What is another name (4-letter initialism) for a queue? How can a queue be implemented using a list? Show how enqueue and dequeue can be accomplished by calling list methods.
> Yes, FILO
```python
L.append() #push
L.pop(0) #pop
```
23. Show how a tuple can be used to implement
a stack's push and pop functionality
```python
t = t[:] + element #push
t = t[:-1] #pop
```
a queue's enqueue and dequeue functionality
```python
t = t[:] + element #push
t = t[1:] #pop
```
24. Is a tuple more or less efficient than a list for implementing the stack and queue data structures? Why?
> It's less efficient, because tuple is immutable so it need to create another new tuple every time you pop and push.
25. What do these built-in functions do?
```python
max(['h', 'e', 'l', 'l', 'o'])
min('hello')
sum([2, 3, 4, 5, 6])
sum(range(10))
any(['', 'apples', 'oranges', 'banana'])
any([0, '', 0.0, [], ()])
any(['0', '', 0.0, [], ()])
any([0, ' ', 0.0, [], ()])
all(['', 'apples', 'oranges', 'banana'])
all([' ', 'apples', 'oranges', 'bananas'])
all([0, '', 0.0, [], ()])
```
```python
'o'
'e'
20
55
True
False
True
True
False
True
False
```
26. What is the non-mutation version of the following statements? Assume L is a list
```python
L.sort()
L.reverse()
L.extend([1, 2, 3])
del(L[1])
L.pop()
```
```python
sorted(L)
reversed(L)
L = L[:] + [1, 2, 3]
L = L[0] + L[2:]
L = L[:-1]
```
27. How do you use list comprehension to create a list with values
```python
['*', '**', '***', '****', '*****']
[1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096]
```
```python
['*'*i for i in range(1, 6)]
[2 ** i for i in range(13)]
```
28. How do you use two-level list comprehension to create a multiplication table in the following format:
```python
[(1, 1, 1), (1, 2, 2), (1, 3, 3), … (1, 9, 9), (2, 1, 2), (2, 2, 4), (2, 3, 6), (2, 4, 8), … (2, 9, 18), (3, 1, 3), (3, 2, 6), (3, 3, 9), … (3, 9, 27), (4, 1, 4) … (4, 9, 36), (5, 1, 5), … (9, 9, 81)]
```
```python
[(i, j, i*j) for i in range(1, 10) for j in range(1, 10)]
```
29. How do you use list comprehension with filter to generate the list of upper-case letters except 'A', 'E', 'I', 'O', 'U'?
```python
[chr(i) for i in range(65, 65+26) if chr(i) not in ['A', 'E', 'I', 'O', 'U']]
```
30. After executing the following sequence of statements:
```python
x = 3
y = x
x = 4
```
what is the value of y?
```python
3
```
31. After executing the following sequence of statements
```python
x = [1, 2, 3]
y = x
x = [4, 5, 6]
```
what is the value of y?
```python
[4, 5, 6]
```
32. After executing the following sequence of statements
```python
x = [1, 2, 3]
y = x
x[1] = 4
```
what is the value of y?
```python
[1, 4, 3]
```
33. After executing the following sequence of statements
```python
x = [1, 2, 3]
y = x[:]
x[1] = 4
```
what is the value of y?
```python
[1, 2, 3]
```
34. After executing the following sequence of statements
```python
x = [1, 2, 3]
y = x
y[:] = [4, 5, 6]
```
what is the value of x?
```python
[4, 5, 6]
```
35. After executing the following sequence of statements
```python
z = ['a', 'b']
x = [1, z, 3]
z.append('c')
```
what is the value of x?
```python
[1, ['a', 'b', 'c'], 3]
```
36. After executing the following sequence of statements
```python
z = ['a', 'b']
x = [1, z, 3]
y = x
z.append('c')
```
what is the value of y?
```python
[1, ['a', 'b', 'c'], 3]
```
37. After executing the following sequence of statements
```python
z = ['a', 'b']
x = [1, z, 3]
y = x[:]
z.append('c')
```
what is the value of y?
```python
[1, ['a', 'b', 'c'], 3]
```
38. After executing the following sequence of statements
```python
z = ['a', 'b']
x = [1, z, 3]
y = x[:]
x[0] = 4
z.append('c')
```
what is the value of y?
```python
[1, ['a', 'b', 'c'], 3]
```
39. After executing the following sequence of statements
```python
import copy
z = ['a', 'b']
x = [1, z, 3]
y = copy.copy(x)
x[0] = 4
z.append('c')
```
what is the value of y?
```python
[1, ['a', 'b', 'c'], 3]
```
40. After executing the following sequence of statements
```python
import copy
z = ['a', 'b']
x = [1, z, 3]
y = copy.deepcopy(x)
x[0] = 4
z.append('c')
```
what is the value of y?
```python
[1, ['a', 'b'], 3]
```
41. What is the type of {}?
> set
42. What is the expression for an empty set?
> set()
43. Which of the following can or cannot be a member of a set? Why?
```python
'hello'
23
44.27
5e-3
2+4j
['Mary', 'had', 'a', 'little', 'lamb'] #not allowed, list is mutable.
('Mary', 'had', 'a', 'little', 'lamb')
{'Mary', 'had', 'a', 'little', 'lamb'} #not allowed, set is mutable.
{'Sun': 0, 'Mon': 1, 'Tue': 2, 'Wed': 3}
True
False
()
[] #not allowed, list is mutable.
{} #not allowed, set is mutable.
```
44. What is the value of len(set('hello'))?
```python
4
```
45. What is the value of each of the following expressions?
```python
{1, 2} - {2, 3}
{1, 2} | {2, 3}
{1, 2} & {2, 3}
{1, 2} ^ {2, 3}
```
```python
{1}
{1, 2, 3}
{2}
{1, 3}
```
46. What is the result of the following comparisons?
```python
{1, 2, 3} > {2, 3}
{1, 2, 3} < {1, 2, 4}
{1, 2, 2, 3} == {1, 2, 3}
{1, 2, 4} != {4, 2, 1}
```
```python
True
False
True
False
```
47. Assume S = {1, 2, 3}, what is the difference between
S = S | {3, 4} and S |= {3, 4}?
> one is mutation another is non-mutation
48. Assume D = {'Sun': 0, 'Mon': 1, 'Tue': 2, 'Wed': 3}
What is the value of D['Mon']?
```python
1
```
What is the value of D after D['Thu'] = 4?
```python
{'Sun': 0, 'Mon': 1, 'Tue': 2, 'Wed': 3, 'Thu':4}
```
Continuing with the previous statement, what is the value of D after D['Sun'] = 7?
```python
{'Sun': 7, 'Mon': 1, 'Tue': 2, 'Wed': 3, 'Thu':4}
```
What happens if you attempt print(D['Fri'])?
```console
KeyError: 'Fri'
```
49. Assume D = {'Sun': 0, 'Mon': 1, 'Tue': 2, 'Wed': 3}
What is the value of D.keys()
```python
dict_keys(['Sun', 'Mon', 'Tue', 'Wed'])
```
What is the value of D.values()
```python
dict_values([0, 1, 2, 3])
```
What is the value of D.items()
```python
dict_items([('Sun', 0), ('Mon', 1), ('Tue', 2), ('Wed', 3)])
```
50. Assuming D = {}, which of the following is legal or not legal in Python? If not legal, why not?
```python
D[()] = 10
D[''] = {}
D[0] = ''
D[{}] = () #illegal, key must be immutable.(set)
D[[]] = set() #illegal, key must be immutable.(list)
D[:] = range(10) #illegal, key must be immutable.(slice)
D[-1] = [-1]
D[(())] = [{}]
```
51. How do you use dictionary comprehension to create a reverse mapping? For example, suppose
```python
D = {'Sun': 0, 'Mon': 1, 'Tue': 2, 'Wed': 3, 'Thu': 4, 'Fri': 5, 'Sat': 6}
```
create its reverse mapping whose value should be
```python
{0: 'Sun', 1: 'Mon', 2: 'Tue', 3: 'Wed', 4: 'Thu', 5: 'Fri', 6: 'Sat'}
```
```python
{v : i for i, v in D.items()}
```
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