Chapter 20

Question 1

call graph

Answer 1

A graph consisting of nodes which represent function frames (or invocations), and directed edges (lines with arrows) showing which frames gave rise to other frames.

Question 2

dictionary

Answer 2

A collection of key:value pairs that maps from keys to values. The keys can be any immutable value, and the associated value can be of any type.

Question 3

immutable data value

Answer 3

A data value which cannot be modified. Assignments to elements or slices (sub-parts) of immutable values cause a runtime error.

Question 4

key

Answer 4

A data item that is mapped to a value in a dictionary. Keys are used to look up values in a dictionary. Each key must be unique across the dictionary.

Question 5

key:value pair

Answer 5

One of the pairs of items in a dictionary. Values are looked up in a dictionary by key.

Question 6

mapping type

Answer 6

A mapping type is a data type comprised of a collection of keys and associated values. Python’s only built-in mapping type is the dictionary. Dictionaries implement the associative array abstract data type.

Question 7

memo

Answer 7

Temporary storage of precomputed values to avoid duplicating the same computation.

Question 8

mutable data value

Answer 8

A data value which can be modified. The types of all mutable values are compound types. Lists and dictionaries are mutable; strings and tuples are not.