Lab Assignment 2

    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 Py-charm2 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 CSDO-MAIN 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
2

3A non-CSE student should ask the TA for a CSDOMAIN account.


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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, MMMMMMMMMCMX-CIX], 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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    • ...

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


    • https://en.wikipedia.org/wiki/Fibonacci_number.


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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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    • 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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        ◦ Subject of your file should be <student-id1>_<student-id2>_lab2 if you are in a two-person group or <student-id1>_lab2 if not.

        ◦ No later than 23:59 on Wednesday. Oct. 21, 2020

    4. Students in the same group would get the same marks. Marks will be deducted if you do not follow the submission rules. Anyone/Anygroup who is caught plagiarizing would get 0 score!


























































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