06 Data structures

Question 1

Data structure

Answer 1

object in program that holds a collection of data

Question 2

array

Answer 2

holds components of a vector, or a list of names

Question 3

Why is it useful to use lists?

Answer 3

we can perform operations on the list, like checking length, sorting names and editing it

Question 4

nested list

Answer 4

list inside a list

Question 5

list

Answer 5

sequence of data, constructed using square brackets

Question 6

len

Answer 6

returns the length of the list

Question 7

enumerate

Answer 7

iterate over a list and get position of each member in the list

Question 8

How does counting differ in python?

Answer 8

Starts from 0

Question 9

append

Answer 9

add elements to a list

Question 10

indexing

Answer 10

assigning number to element
indices start from 0 and run to (length-1)

Question 11

Why is it better to iterate rather than index?

Answer 11

there are data structures that support iterations but which do not support indexing

Question 12

Heterogeneous data structure

Answer 12

Store mixed types
python lists are an example

Question 13

Homogenous data structures

Answer 13

store only one type
arrays are an example - more efficient generally

Question 14

list comprehension

Answer 14

succinctly built lists from other lists

Question 15

What is the difference between a tuple and list?

Answer 15

It is a list that cannot be changed after it has been created - it is immutable
Tuples also use round brackets

Question 16

Why is it useful to see a list that cannot be changed?

Answer 16

safer since cannot be accidentally modified in the program
permits implementations to possibly exploit this to optimise for speed

Question 17

dictionary

Answer 17

Can build a map from keys and values
Each entry separated by comma

Question 18

How do you declare a dictionary

Answer 18

Curly brackets
Entry separated by comma

Question 19

Why is choosing the right data structure an important decision in programming

Answer 19

Affects the program’s efficiency, memory usage, flexibility, and ease of development

Question 20

What is the general trade-off between flexible and simple data structures?

Answer 20

More flexible data structures are usually less efficient and may use more memory than simpler ones

Question 21

What should you prioritise when efficiency is not critical?

Answer 21

Choose a data structure that provides the needed functionality, flexibility and ease of use

Question 22

Why should safety be considered when choosing a data structure?

Answer 22

Some data structures prevent modification, reducing the risk of errors

Question 23

Why should you use iterators rather than indexing

Answer 23

Allows switching from data structures that support indexing to data structures that do not support indexing