Week 07 Laboratory Exercises
Objectives
- Getting used to Python programing.
- Practice text processing in Python.
- Practice using regex in Python.
Preparation
Before the lab you should re-read the relevant lecture slides and their accompanying examples.
Getting Started
lab07 and changing to this directory.
mkdir lab07 cd lab07
There are some provided files for this lab which you can fetch with this command:
2041 fetch lab07
If you're not working at CSE, you can download the provided files as a zip file or a tar file.
Exercise:
How many Orcas in that File?
A citizen science project monitoring whale populations has files of containing large numbers of whale observations. Each line in these files contains:
- the date the observation was made
- the number of whales in the pod ("pod" is the collective number for a group of whales)
- the species of whale
head whales0.txt 18/01/18 9 Pygmy right whale 01/09/17 21 Southern right whale 16/02/18 4 Striped dolphin 02/07/17 4 Common dolphin 19/02/18 4 Blue whale 21/02/18 38 Dwarf sperm whale 14/06/17 29 Southern right whale 20/06/17 3 Spinner dolphin 22/07/17 34 Indo-Pacific humpbacked dolphin 20/03/18 7 Long-finned pilot whale
Write a Python program orca.py which prints a count of the number of observations of Orcas in the files.
Your program should take 1 or more filenames as command line arguments.
./orca.py whales0.txt 1245 Orcas reported ./orca.py whales0.txt whales1.txt whales2.txt 3150 Orcas reported
Note: each line records one pod of whales
Your program should print the number of individual Orca observed - it needs to sum each pod of Orcas.
When you think your program is working,
you can use autotest
to run some simple automated tests:
2041 autotest orca
When you are finished working on this exercise,
you must
submit your work by running give:
give cs2041 lab07_orca orca.py
before Monday 15 July 12:00 (midday) (2024-07-15 12:00:00) to obtain the marks for this lab exercise.
Exercise:
Printing A summary of All Whale Species
Write a Python program whale_summary.py which take one or more files on the command line.
whale_summary.py should print for, every whale species in the file, how many pods were seen and how many total whales were seen of that species.
Whale species should be listed in alphabetic order.
All whale names should be converted to lower case.
All whale names should be converted to singular form - assume this can be done safely by deleting a trailing 's' if it is present.
./whale_summary.py whales0.txt blue whale observations: 51 pods, 1171 individuals bryde's whale observations: 47 pods, 1023 individuals coastal bottlenose dolphin observations: 53 pods, 1169 individuals common dolphin observations: 62 pods, 1232 individuals dwarf minke whale observations: 49 pods, 1080 individuals dwarf sperm whale observations: 58 pods, 1272 individuals fin whale observations: 65 pods, 1251 individuals humpback whale observations: 55 pods, 1071 individuals indo-pacific humpbacked dolphin observations: 43 pods, 897 individuals long-finned pilot whale observations: 50 pods, 996 individuals orca observations: 53 pods, 1245 individuals pygmy right whale observations: 59 pods, 1260 individuals pygmy sperm whale observations: 57 pods, 1346 individuals sei whale observations: 55 pods, 929 individuals short-finned pilot whale observations: 68 pods, 1344 individuals southern right whale observations: 55 pods, 1252 individuals spinner dolphin observations: 52 pods, 1118 individuals striped dolphin observations: 68 pods, 1337 individuals ./whale_summary.py messy_whales0.txt blue whale observations: 2 pods, 27 individuals dwarf minke whale observations: 6 pods, 132 individuals orca observations: 2 pods, 48 individuals
When you think your program is working,
you can use autotest
to run some simple automated tests:
2041 autotest whale_summary
When you are finished working on this exercise,
you must
submit your work by running give:
give cs2041 lab07_whale_summary whale_summary.py
before Monday 15 July 12:00 (midday) (2024-07-15 12:00:00) to obtain the marks for this lab exercise.
Exercise:
Find the sum of all numbers in a file
Write a Python program summing_numbers.py which given a file as a command line argument, prints the sum of all the numbers in the file.
A number for the purposes of this exercise is any sequence of consecutive digits.
Note only the digits 0-9 are considered parts of numbers. The characters '.' and '-' are not considered part of numbers.
For example, the string the "It was -42.5C outside" should be treated as containing the numbers 42 and 5.
./summing_numbers.py A-Tale-of-Two-Cities.txt 7104 ./summing_numbers.py Pride-and-Prejudice.txt 46520
When you think your program is working,
you can use autotest
to run some simple automated tests:
2041 autotest summing_numbers
When you are finished working on this exercise,
you must
submit your work by running give:
give cs2041 lab07_summing_numbers summing_numbers.py
before Monday 15 July 12:00 (midday) (2024-07-15 12:00:00) to obtain the marks for this lab exercise.
Challenge Exercise:
A Python Program that Prints Python
Write a Python program python_print.py which is given a single argument. It should output a Python program which when run, prints this string. For example:
./python_print.py "hello world, how are you?" | python3 hello world, how are you? ./python_print.py "I'm So Meta, Even This Acronym" > new_program.py chmod +x new_program.py ./new_program.py I'm So Meta, Even This Acronym
When you think your program is working,
you can use autotest
to run some simple automated tests:
2041 autotest python_print
When you are finished working on this exercise,
you must
submit your work by running give:
give cs2041 lab07_python_print python_print.py
before Monday 15 July 12:00 (midday) (2024-07-15 12:00:00) to obtain the marks for this lab exercise.
Challenge Exercise:
A Python Program that Prints Python that Prints Python that ...
Write a Python program python_print_n.py which is given a two arguments, an integer n and a string.
If n is 1 it should output a Python program which prints the string.
If n is 2 it should output a Python program which prints a Python program which prints the string.
If n is 3 it should output a Python program which prints a Python program which prints a Python program which prints the string.
And so on for any value of n.
./python_print_n.py 1 "hello world, how are you?" | python3 hello world, how are you? ./python_print_n.py 2 "hello world, how are you?" | python3 | python3 hello world, how are you? ./python_print_n.py 3 "hello world, how are you?" | python3 | python3 | python3 hello world, how are you? ./python_print_n.py 10 "Now that's a lot of python" | python3 | python3 | python3 | python3 | python3 | python3 | python3 | python3 | python3 | python3 Now that's a lot of python
When you think your program is working,
you can use autotest
to run some simple automated tests:
2041 autotest python_print_n
When you are finished working on this exercise,
you must
submit your work by running give:
give cs2041 lab07_python_print_n python_print_n.py
before Monday 15 July 12:00 (midday) (2024-07-15 12:00:00) to obtain the marks for this lab exercise.
Challenge Exercise:
A Python Program that Prints itself forever
Write a Python program python_print_inf.py which prints it's own soruce code.
The program can not use the open function.
The program can not use the inspect module.
./python_print_inf.py > new_program.py diff -s python_print_inf.py new_program.py Files python_print_inf.py and new_program.py are identical chmod +x new_program.py ./new_program.py > second_order_program.py diff -s python_print_inf.py second_order_program.py Files python_print_inf.py and second_order_program.py are identical ./python_print_inf.py | python3 | python3 | python3 | python3 | python3 > nth_program.py diff -s python_print_inf.py nth_program.py Files python_print_inf.py and nth_program.py are identical
When you think your program is working,
you can use autotest
to run some simple automated tests:
2041 autotest python_print_inf
When you are finished working on this exercise,
you must
submit your work by running give:
give cs2041 lab07_python_print_inf python_print_inf.py
before Monday 15 July 12:00 (midday) (2024-07-15 12:00:00) to obtain the marks for this lab exercise.
Submission
give.
You can run give multiple times.
Only your last submission will be marked.
Don't submit any exercises you haven't attempted.
If you are working at home, you may find it more convenient to upload your work via give's web interface.
Remember you have until Week 8 Monday 12:00:00 (midday) to submit your work.
You cannot obtain marks by e-mailing your code to tutors or lecturers.
You check the files you have submitted here.
Automarking will be run by the lecturer several days after the submission deadline,
using test cases different to those autotest runs for you.
(Hint: do your own testing as well as running autotest.)
After automarking is run by the lecturer you can view your results here. The resulting mark will also be available via give's web interface.
Lab Marks
When all components of a lab are automarked you should be able to view the the marks via give's web interface or by running this command on a CSE machine:
2041 classrun -sturec