Chapter 11

Question 1

dictionary

Answer 1

a mapping from a set of keys to their corresponding values

Question 2

key-value pair

Answer 2

the representation of the mapping from a key to a value

Question 3

item

Answer 3

another name for a key-value pair

Question 4

key

Answer 4

an object that appears in a dictionary as the first part of a key-value pair

Question 5

value

Answer 5

an object that appears in a dictionary as the second part of a key-value pair. This is more specific than our previous use of the word ‘value’.

Question 6

implementation

Answer 6

a way of performing a computation

Question 7

hashtable

Answer 7

the algorithm used to implement Python dictionaries.

Question 8

hash function

Answer 8

a function used by a hashtable to compute the location for a key

Question 9

hashable

Answer 9

a type that has a hash function. Immutable types like integers, floats, and strings are hashable; mutable types like lists and dictionaries are not.

Question 10

lookup

Answer 10

a dictionary operation that takes a key and finds the corresponding value.

Question 11

reverse lookup

Answer 11

a dictionary operation that takes a value and finds one or more keys that map to it.

Question 12

singleton

Answer 12

a list (or other sequence) with a single element.

Question 13

call graph

Answer 13

a diagram that shows every frame created during the execution of a program, with an arrow from each caller to each callee.

Question 14

histogram

Answer 14

a set of counters

Question 15

memo

Answer 15

a computed value stored to avoid unnecessary future computation