Python Statements

Question 1

What is a for loop?

Answer 1

A for loop is used for iterating over a sequence (that is either a list, tuple, dictionary or a string)

example

mylist = [‘cherry’, ‘banana’, 5, 6]

for item in mylist:
    print(item)
    if item == 'banana':
        print("I hit the number 5")
        break
OUTPUT

cherry
banana
I hit the number 5

Question 2

What is the continue statement?

Answer 2

The continue statement stops the current iteration of the loop, and continues with the next one. Basically it skips an item.

fruits = [“apple”, “banana”, “pear”]

for item in fruits:
if item == “banana”:
continue
print (item)

OUTPUT

apple
pear

Question 3

What is a nested loop?

Answer 3

A nested loop is a loop, inside of a loop. Loop-ception.

adj = ["red", "big", "tasty"]
fruits = ["apple", "banana", "pear"]

for item in adj:
for fruit in fruits:
print (x, y)

Question 4

How do you import a function from a library?

Answer 4

press tab after import to select list of functions from the library

from random from random import randint

randint(0,100)

OUTPUT 
#random number

Question 5

How do you save a randint generated number?

Answer 5

savedrandomnumber = randint(0,10)

Question 6

How do you accept user input?

Answer 6

By using in input function

userinput = input(‘Enter a number here: ‘)

Question 7

What is the enumerate function?

Answer 7

The enumerate function essentially creates an index count for the string ‘abcdef’ in the form of tuples.

word = ‘abc’

for item in enumerate(word):
print(item)

OUTPUT
(0, ‘a’)
(1, ‘b’)
(2, ‘c’)

Question 8

How do you unpack an enumerated string?

Answer 8

word = ‘ghi’

for index,letter in enumerate(word):
print(index)
print(letter)
print(‘\n’)

OUTPUT
0
g

1
h

2
i

Question 9

What is List comprehension?

Give example

Answer 9

It’s essentially one line for loop built inside of brackets.

Example:

1st = [x for x in ‘word’]
OUTPUT
[‘w’, ‘o’, ‘r’, ‘d’]

mylist = [x for x in range(0,51) if x%3 ==0]
OUTPUT
mylist
[0, 3, 6, 9, 12, 15, …]

Question 10

How could you square a number in range() and turn it into a list comprehension?

Answer 10

Example:
1st = [x**2 for x in range(0,11)]

OUTPUT

[0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

Question 11

How do you add a if statement in a list comprehension?

Answer 11

Example:

1st = [x for xx in range(11) if x % 2 == 0]

OUTPUT
[0, 2, 4, 6, 8, 10]

Question 12

How would you perform a nested list comprehension?

Answer 12

1st = [ x2 for x in [x2 for x in range(11)]]

OUTPUT

[0, 1, 16, 81, 256, 625, 1296, 2401, 4096, 6561, 10000]