Introduction to Python Lab Assignment 2

CSCI 2040: Introduction to Python
Lab Assignment 2

Notes
1. You are allowed to form a group of two to do this lab assignment.
2. You are strongly recommended to bring your own laptop to the lab with Anaconda1 and Pycharm2
installed. You don’t even have to attend the lab session if you know what you are
required to do by reading this assignment.
3. Only Python 3.x is acceptable. You need to specify your python version as the first line in
your script. For example, if your scripts are required to run in Python 3.6, the following line
should appear in the first line of your scripts:
#python_version == '3.6'
4. For those of you using the Windows PC in SHB 924A (NOT recommended) with your CSDOMAIN account3
, please login and open “Computer” on the desktop to check if an “S:” drive is
there. If not, then you need to click “Map network drive”, use “S:” for the drive letter, fill in
the path \\ntsvr1\userapps and click “Finish”. Then open the “S:” drive, open the Python3
folder, and click the “IDLE (Python 3.7 64-bit)” shortcut to start doing the lab exercises. You
will also receive a paper document and if anything has changed, please be subject to the paper.
5. Your code should only contain specified functions. Please delete all the debug statements (e.g.
print) before submission.
Exercise 1 (20 marks)
Please use list comprehension to write function check_sublist(list1, d1, d2) in the script
p1.py which takes a list of numbers list1, and two integers d1 and d2 as arguments and return
lista: a list of numbers in list1 that are larger than d1*d2, listb: a list of numbers in list1
that are smaller than d1*d2, listc: a list of numbers in list1 that are smaller than d1 or d2. You
can assume that list1 is a non-empty list and d1, d2 are two positive integers. Please make sure
that your test code is not allowed in the file, and the prototype of the function check_sublist is
given as follows:
def check_sublist(list1, d1, d2):
# your statement follows
# ...
return lista, listb, listc
1An open data science platform powered by Python. https://www.continuum.io/downloads
2A powerful Python IDE. https://www.jetbrains.com/pycharm/download/
3A non-CSE student should ask the TA for a CSDOMAIN account.
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CSCI 2040 Lab Assignment 2 Page 2
Testing: Suppose you saved your script p1.py in C:\Users\USERNAME \Documents\lab2. In IDLE,
you should test your script p1.py in the Python shell with
>>> import sys
>>> sys.path.append(r”C:\Users\USERNAME \Documents\lab2”)
>>> import p1
>>> print(p1.check_sublist([21, 25, 4, 6, 28], 3, 7))
([25, 28], [4, 6], [4, 6])
Note: if you editted your script file in the testing procedure, you need to reload the imported
module before you call any functions. E.g.,
# For Python3:
>>> from importlib import reload
>>> reload(p1)
Exercise 2 (20 marks)
The numeric system represented by Roman numerals is based on the following seven symbols
(with corresponding Arabic values):
Symbol I V X L C D M
Value 1 5 10 50 100 500 1000
The correspondence between the first nine (Arabic) decimal numbers and the Roman numerals and
other basic combiniations are shown as below:
Symbol I II III IV V VI VII VIII IX
Value 1 2 3 4 5 6 7 8 9
Symbol X XX XXX XL L LX LXX LXXX XC
Value 10 20 30 40 50 60 70 80 90
Symbol C CC CCC CD D DC DCC DCCC CM
Value 100 200 300 400 500 600 700 800 900
Symbol M MM MMM MMMM M*5 M*6 M*7 M*8 M*9
Value 1000 2000 3000 4000 5000 6000 7000 8000 9000
where M*5=MMMMM and so on. For example:
LXXIV=L+XX+IV=50+20+4=74
CMXCIX=CM+XC+IX=900+90+9=999
MMMMMMMDCCLXVI=MMMMMMM+DCC+LX+VI=7000+700+60+6=7766
Write a function roman_to_decimal in the script p2.py that takes a Roman numerals string
as an argument and return a decimal integer whose value is equivalent to its corresponding Roman
numerals. Your function only needs to process the string in the range [I, MMMMMMMMMCMXCIX], i.e. [1, 9999]. For this exercise, you don’t need to check whether str is a correct Roman
numberal string. For the corresponding integer less than 1 or greater than 9999, the function
should return “-1”. The prototype of the function roman_to_decimal is given as follows:
def roman_to_decimal(str):
# your statement follows
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CSCI 2040 Lab Assignment 2 Page 3
# ...
return n
Testing: Suppose you saved your script p2.py in C:\Users\USERNAME \Documents\lab2. In IDLE,
you should test your script p2.py in the Python shell with
>>> import sys
>>> sys.path.append(r”C:\Users\USERNAME \Documents\lab2”)
>>> import p2
>>> print(p2.roman_to_decimal(’CMLV’))
955
>>> print(p2.roman_to_decimal(’XCVI’))
96
Exercise 3 (20 marks)
Python allows recursive function, i.e., a function that can call itself. As we know, in a Fibonacci
sequence, each number is the sum of the two preceding ones4
.
xn+1 = xn + xn−1.
In this lab, we want to compute the Fibonacci number. When a newly computed number is larger
than 1000, the method stops and outputs the number.
For example, starting from x1 = 50 and x2 = 60, we obtain a sequence:
50, 60, 110, 170, 280, 450, 730, 1180
And finally the algorithm returns 1180.
Using the observations above, write a recursive function fibo that calls itself in the script
p3.py to compute the Fibonacci number. Suppose x1 and x2 are two initial Fibonacci numbers
which are integers and larger than 0, the prototype of the function fibo is given as follows:
def fibo(x1, x2):
# x1 and x2 are initial numbers
# your statement follows
# ...
return value # value is the smallest Fibonacci number which is larger than 1000
Testing: Suppose you saved your script p3.py in C:\Users\USERNAME \Documents\lab2. In IDLE,
you should test your script p3.py in the Python shell with
>>> import sys
>>> sys.path.append(r”C:\Users\USERNAME \Documents\lab2”)
>>> import p3
>>> val = p3.fibo(50, 60)
>>> print(val)
1180
4
https://en.wikipedia.org/wiki/Fibonacci_number.
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CSCI 2040 Lab Assignment 2 Page 4
Exercise 4 (20 marks)
Write a group of required functions for triangle processing in the script p4.py. If you want to
calculate a square root, please use math.sqrt(), since the test script use this function to generate
the standard answer.
• The input triangle should be a tuple (a,b,c), where the numeric arguments a, b and c are
sides long of the triangle.
• Implement the check_invalid(triangle) function and return the Boolean value True if the
input triangle is not valid, otherwise False. The input triangle is considered valid if and
only if it is a tuple with three positive numbers and any two sides of a triangle must be greater
than the length of the third side.
• Implement the is_isosceles_triangle(triangle) function and return the Boolean value
True or False to indicate whether the input triangle is valid and is a isosceles one.
• Implement the area(triangle) and perimeter(triangle) functions to return the numerical
value of the area and perimeter of the input triangle. (Hint: triangle’s area can be calculated
by Heron’s formula: T =
√
s(s − a)(s − b)(s − c), where s is half of its perimeter.)
Testing: Suppose you saved your script p4.py in C:\Users\USERNAME \Documents\lab2. In IDLE,
you should test your script p4.py in the Python shell with
>>> import sys
>>> sys.path.append(r”C:\Users\USERNAME \Documents\lab2”)
>>> import p4
>>> t1 = (5, 5, 6)
>>> p4.is_isosceles_triangle(t1)
True
>>> p4.area(t1)
12.0
>>> p4.perimeter(t1)
16
>>> t2 = (3, 6, 1)
>>> p4.check_invalid(t2)
True
Exercise 5 (20 marks)
Write a group of required functions for text processing in the script p5.py.
• The input test_string should be a single string.
• Implement the count_alphabet(test_string) function and return the number of alphabetic
characters (a-z and A-Z) in the test_string.
• Implement the vowel_capitalization(test_string) function and return the string with
the vowels (a, e, i) capitalized.
• Implement the concat(test_string, new_string) function and return a string that is the
concatenation of test_string and new_string.
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CSCI 2040 Lab Assignment 2 Page 5
• Implement the search(test_string, sub) function and return the highest index in test_string
where substring sub is found. If not found, it returns -1.
• Implement the letter_count(test_string) function and return a list of tuples (char,
count), where char is the character that is in test_string and count is the number of
times char appears:
– You should only care about English characters a–z and A–Z.
– The counting is case-insensitive. You should regard uppercase letters as lowercase letters.
– The output list should be sorted by char in alphabetic order.
Testing: Suppose you saved your script p5.py in C:\Users\USERNAME \Documents\lab2. In IDLE,
you should test your script p5.py in the Python shell with
>>> import sys
>>> sys.path.append(r”C:\Users\USERNAME \Documents\lab2”)
>>> import p5
>>> test_str = "Alice was born in 1996 and born in London."
>>> p5.count_alphabet(test_str)
29
>>> p5.vowel_capitalization(test_str)
’AlIcE wAs born In 1996 And born In London.’
>>> p5.concat(test_str, " She is 22 now.")
’Alice was born in 1996 and born in London. She is 22 now.’
>>> p5.search(test_str, "born")
27
>>> p5.search(test_str, "now")
-1
>>> p5.letter_count("The quick brown fox jumps over the lazy dog")
[(’a’, 1), (’b’, 1), (’c’, 1), (’d’, 1), (’e’, 3), (’f’, 1), (’g’, 1), (’h’, 2), (’i’,
1), (’j’, 1), (’k’, 1), (’l’, 1), (’m’, 1), (’n’, 1), (’o’, 4), (’p’, 1), (’q’, 1),
(’r’, 2), (’s’, 1), (’t’, 2), (’u’, 2), (’v’, 1), (’w’, 1), (’x’, 1), (’y’, 1), (’z’,
1)]
Submission rules
1. Please name the functions and script files with the exact names specified in this assignment
and test all your scripts. Any script that has any wrong name or syntax error will not be marked.
2. For each group, please pack all your script files as a single archive named as
<student-id1>_<student-id2>_lab2.zip
For example, 1155012345_1155054321_lab2.zip, i.e., just replace <student-id1> and <student-id2>
with your own student IDs. If you are doing the assignment alone, just leave <student-id2>
empty, e.g, 1155012345_lab2.zip.
3. Upload the zip file to your blackboard ( https://blackboard.cuhk.edu.hk),
• Only one member of each group needs to upload the archive file.
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CSCI 2040 Lab Assignment 2 Page 6
• Subject of your file should be <student-id1>_<student-id2>_lab2 if you are in a twoperson group or <student-id1>_lab2 if not.