Comp Prog 1284: Exam 2

Lists, Loops, and Functions

Container

an object that groups related objects together

Mutable

value can be changed after it has been created (EX. lists, dictionaries)

Immutable

value can not be changed after it has been created (EX. numbers, strings, tuples)

List

a mutable container, meaning the size of this can grow or shrink and elements within can change

Items in a list are called…

elements

Code for creating a list

list()

Another way to create a list (EX. put 1, 2, & 3 into my_list)

my_list = [1, 2, 3]

Index

a zero-based integer matching to a specific position in the list’s sequence of elements

Code for indexing in a list (EX. trying to find the 2nd item in my_list)

my_list[1]

A list’s index must be an _______ type

integer

In-place modifications

the ability to grow or shrink a list

Code for changing the value of element at index i in my_list

my_list[i] = x

Lists are used to help ______ the number of variables created

reduce

Methods

instruct an object to perform some action

my_list.append(‘m’)

adds the value ‘m’ to the end of the list

my_list.pop(1)

removes the element at index 1

my_list.remove(‘m’)

removes the first element whose value is ‘m’

Sequence-type functions and methods

built-in functions and methods that operate on sequences like lists and strings

max(my_list)

finds the element in the list with the largest value (even letters have values)

min(my_list)

finds the element in the list with the smallest value

sum(my_list)

finds the total of all elements of a list (numbers only)

my_list.index(‘m’)

finds the index of the first element that matches the value ‘m’

my_list.count(‘m’)

finds how many times the value ‘m’ is in the list

my_list.extend([4, 12])

adds all items (4 & 12) to the list

my_list = [3, 5]

my_list.insert(3, 8)

inserts value 8 into position before 3

my_list = [8, 3, 5]

my_list = [4, 3, 7, 5]

my_list.sort()

puts the elements in order

my_list = [3, 4, 5, 7]

my_list.reverse()

reverses the order of elements in the list

Slice notation

to read multiple elements from a list, creating a new list that contains only the desired elements (EX. my_list[0:2])

Negative indices can be used to count _________ from the end of the list (my_list[0,-1])

backwards

Stride

indicates how many elements are skipped between extracted items in the list (EX. my_list[0:5:2])

List nesting

embedding a list inside another list

EX. my_list = [3, [5, 13], 8]

Programmers can access all elements of nested lists by using…

nested for loops

split()

divides a string into a list of tokens

Token

a substring that forms a part of a larger string

Separator

a character that indicates where to split the string into tokens (EX. string.split(‘#’))

join()

performs the inverse operation of split to create a single string

Parameters

variables listed inside parentheses in a function

Arguments

actual values passed to a function when called