Python Statements

Question 1

How does a for loop act as an iterator in python?

Answer 1

It goes through items that are in a sequence or any other iterable item, performing operations on each item as a stand alone object.

Question 2

What objects can be iterated?

Answer 2

Strings, lists, tuples, and built in iterables for dictionaries (keys or values)

Question 3

What should the iteration obtained item be named in a for loop?

Answer 3

That is up to the coder, it better make sense though.

Question 4

What is tuple unpacking?

Answer 4

If you are iterating through a sequence that contains tuples, the item can actually be the tuple itself. Ex: for a,b in list1: print(tup)

Question 5

With tuples in a sequence, we can access the items inside of them through ___. Why is this important?

Answer 5

unpacking Many objects will deliver their iterables through tuples

Question 6

list 3 methods for extracting lists from dictionaries.

Answer 6

when wrapped in the list() function: .keys() - returns a list of keys .values() - returns a list of values .items() - Returns a list of tuples

Question 7

If you want to return a sorted list of dictionary view objects, what function should you use?

Answer 7

Ex: sorted(d.values())

Question 8

what 3 statements can we use to add functionality to while loops?

Answer 8

break: breaks out of the current closest enclosing loop. continue: goes to the top of the closest enclosing loop. Pass: does nothing at all

Question 9

Where are break and continue statements usually place?

Answer 9

Nested in conjunction with an if statement to perform an action based on some condition.

Question 10

What function allows you to generate a list of integers?

Answer 10

range() with parameters for (start,stop,step) *the stop number will not be included

Question 11

What is a generator function?

Answer 11

A special type of function that will generate information and not need to save it to memory.

Question 12

What does the enumerate function do?

Answer 12

Turns a list into a list of tuples with the first item in the pair being the index position of the second item.

Question 13

What is the zip function used for?

Answer 13

quickly generate a list of tuples by “zipping” up together to lists Ex: zip(list1,list2)

Question 14

What else can the in operator be used for?

Answer 14

To quickly check if an object is in a list

Question 15

What functions give you the min or max of a numerical list?

Answer 15

min()

max()

Question 16

name and describe the functionality of the two random library functions mentioned in this chapter.

Answer 16

shuffle() – shuffles the items in the list

randint() –returns a random integer in the range provided by two parameters

Question 17

Explain the structure of a list comprehension.

Answer 17

new_list = [x for x in old_list] translation: return x for every item x(could be manipulated) in list old_list.

Question 18

How do you add an if statement to a list comprehension?

Answer 18

Just add the syntax of the if statement to the end of the list comprehension.

Question 19

How do you do a nest list comprehension?

Answer 19

after “in” in the higher level list comprehension, put the syntax of the nest list comprehension.