Homework help

[David C. Ullrich]

On Tue, 1 Apr 2008 09:11:12 -0700 (PDT), bobby.connor at gmail.com wrote:

>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

I can see at least two possible approaches:

Approach 1:
  (i) post the problems on the internet
  (ii) carefully copy the solutions

Approach 2:
  (i) learn a little bit about the material you were supposed to learn
  
I'll leave the second step in Approach 2 as an exercise...

>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)[0]
>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([1]) should evaluate to True while isAscending([1,2,2])
>should return False.

David C. Ullrich