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

#  (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

>>> (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)[0]

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([1]) should evaluate to True while isAscending([1,2,2])
should return False.

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