Description
Arguably, this is the most important lab of this semester
Starting Lab 7
• Open a browser and log into Brightspace
• On the left hand side under Labs tab, find lab6 material
contained in lab7-students.pdf file
• Download that file to the Desktop.
2
Before starting, always make sure you
are running Python 3
This slide is applicable to all labs, exercises, assignments … etc
ALWAYS MAKE SURE FIRST that you are running Python 3
That is, when you click on IDLE (or start python any other way)
look at the first line that the Python shell displays. It should say
Python 3 (and then some extra digits)
If you do not know how to do this, read the material provided
with Lab 1. It explains it step by step
3
Programming Exercises (the most important lab)
The following exercises are easily the most important exercises in this
whole semester. Solving these problems (by yourself preferably) should
greatly increase your understanding of computational problem solving
and programming.
Do as many as possible (preferably all) of the following 13 programming
exercises from your textbook by Perkovic. 11 out of 13 are mandatory
for this lab (your choice which 11) — see the slides to come.
Introduction to Computing Using Python: An Application Development
Focus, 2nd Edition, Ljubomir Perkovic
Sometimes the author uses a word “outputs”. By that he means “prints”
First recall from the next 4 slides, list (and few string) functions and
methods that you will need.
Introduction to Computing Using Python by Lj. Perkovic
List operators and functions
Like strings, lists can be manipulated with
operators and functions
>>> lst = [1, 2, 3]
>>> lstB = [0, 4]
>>> 4 in lst
False
>>> 4 not in lst
True
>>> lst + lstB
[1, 2, 3, 0, 4]
>>> 2*lst
[1, 2, 3, 1, 2, 3]
>>> lst[0]
1
>>> lst[1]
2
>>> lst[-1]
3
>>> len(lst)
3
>>> min(lst)
1
>>> max(lst)
3
>>> sum(lst)
6
>>> help(list
…
Usage Explanation
x in lst x is an item of lst
x not in lst x is not an item of lst
lst + lstB Concatenation of lst and lstB
lst*n, n*lst Concatenation of n copies of lst
lst[i] Item at index i of lst
len(lst) Number of items in lst
min(lst) Minimum item in lst
max(lst) Maximum item in lst
sum(lst) Sum of items in lst
Introduction to Computing Using Python by Lj. Perkovic
Lists methods
>>> lst = [1, 2, 3]
>>> lst.append(7)
>>> lst.append(3)
>>> lst
[1, 2, 3, 7, 3]
>>> lst.count(3)
2
>>> lst.remove(2)
>>> lst
[1, 3, 7, 3]
>>> lst.reverse()
>>> lst
[3, 7, 3, 1]
>>> lst.index(3)
0
>>> lst.sort()
>>> lst
[1, 3, 3, 7]
>>> lst.remove(3)
>>> lst
[1, 3, 7]
>>> lst.pop()
7
>>> lst
[1, 3]
Usage Explanation
lst.append(item) adds item to the end of lst
lst.count(item) returns the number of times item
occurs in lst
lst.index(item) Returns index of (first occurrence of)
item in lst
lst.pop() Removes and returns the last item in lst
lst.remove(item) Removes (the first occurrence of) item
from lst
lst.reverse(item) Reverses the order of items in lst
lst.sort(item) Sorts the items of lst in increasing
order
Methods append(), remove(), reverse(),
and sort() do not return any value; they, along
with method pop(), modify list lst
Introduction to Computing Using Python by Lj Perkovic
String operators >>> ‘Hello, World!’
‘Hello, World!’
>>> s = ‘rock’
>>> t = ‘climbing’
>>> s == ‘rock’
True
>>> s != t
True
>>> s < t False >>> s > t
True
>>> s + t
‘rockclimbing’
>>> s + ‘ ‘ + t
‘rock climbing’
>>> 5 * s
‘rockrockrockrockrock’
>>> 30 * ‘_’
‘______________________________’
>>> ‘o’ in s
True
>>> ‘o’ in t
False
>>> ‘bi’ in t
True
>>> len(t)
8
Usage Explanation
x in s x is a substring of s
x not in s x is not a substring of s
s + t Concatenation of s and t
s * n, n * s Concatenation of n copies of s
s[i] Character at index i of s
len(s) (function) Length of string s
>> help(str)
Help on class str in module builtins:
class str(object)
| str(string[, encoding[, errors]]) -> str
…
To view all operators, use the help() tool
Usage Explanation
s.capitalize() returns a copy of s with first character
capitalized
s.count(target) returns the number of occurences of
target in s
s.find(target) returns the index of the first
occurrence of target in s
s.lower() returns lowercase copy of s
s.replace(old, new) returns copy of s with every
occurrence of old replaced with new
s.split(sep) returns list of substrings of s,
delimited by sep
s.strip() returns copy of s without leading and
trailing whitespace
s.upper() returns lowercase copy of s
