# Homework help

bobby.connor at gmail.com bobby.connor at gmail.com
Tue Apr 1 18:11:12 CEST 2008

```Hey guys
I haev this homework assignment due today
I don't necessarily want the answers, but need help on how to approach
it/the steps i need to solve the problems
Thanks

#  (2 Points) Write a python function howMany(item,lst) which accepts
an item and a lst of items and returns the number of times item occurs
in lst. For example, howMany(3,[1,2,3,2,3]) should return 2.

# (2 Points) Write a python function upTo(n) which accepts a non-
negative number n and returns a list of numbers from 0 to n. For
example, upTo(3) should return the list [0, 1, 2, 3].

# (2 Points) Write a python function duplicate(lst) which accepts a
lst of items and returns a list with the items duplicated. For
example, duplicate([1,2,2,3]) should return the list [1, 1, 2, 2, 2,
2, 3, 3].

# (2 Points) Write a python function dotProduct(a,b) which accepts two
lists of integers a and b that are of equal length and which returns
the dot product of a and b. I.e., the sum a0 * b0 + ... + an-1 * bn-1
where n is the length of the lists. For example:

dotProduct([1,2,3],[4,5,6]) is 1*4 + 2*5 + 3*6 = 4 + 10 + 18 = 32

# (2 Points) A pair (exp0, exp1) is a combination of expressions that
are attached together by their joint membership in the pair. For
example:

>>> (1+2, 'This')
(3, 'This')

A component of a pair can be obtained using an index in brackets as
with lists (and strings!). For example:

>>> (33,44)
33

Write a function zip(lst1, lst2) such that zip accepts two equal
length lists and returns a list of pairs. For example, zip(['a', 'b',
'c'], [10, 20, 30]) should evaluate to the list [('a', 10), ('b', 20),
('c', 30)].

# (2 Points) Write a function unzip(lst) such that unzip accepts a
list of pairs and returns two lists such that lst == zip(unzip(lst)).
For example, unzip([('a', 10), ('b', 20), ('c', 30)] should evaluate
to the pair (['a', 'b', 'c'], [10, 20, 30]).

# (2 Points) Write a python function isAscending(lst) which accepts a
non-empty list of integers and returns True if the numbers in the list
are in ascending order. Otherwise it should return False. For example,
isAscending() should evaluate to True while isAscending([1,2,2])
should return False.

```