Project 2: CS 61A Autocorrected Typing Software
Programmers dream of
Abstraction, recursion, and
Typing really fast.
Introduction
Due Dates:
- Submit Phase 1 by Tuesday, 7/13.
- Submit the whole project by Tuesday, 7/20.
- You will receive an early submission bonus point for submitting the entire project by Monday, 7/19.
You may work with a partner for the entire project.
In this project, you will write a program that measures typing speed. Additionally, you will implement typing autocorrect, which is a feature that attempts to correct the spelling of a word after a user types it. This project is inspired by typeracer.
Final Product
Our staff solution to the project can be interacted with at cats.cs61a.org - if you'd like, try it out now! When you finish the project, you'll have implemented a significant part of this game yourself!
Download starter files
You can download all of the project code as a zip archive. This
project includes several files, but your changes will be made only to
cats.py
. Here are the files included in the archive:
cats.py
: The typing test logic.utils.py
: Utility functions for interacting with files and strings.ucb.py
: Utility functions for CS 61A projects.data/sample_paragraphs.txt
: A file containing text samples to be typed. These are scraped Wikipedia articles about various topics.data/common_words.txt
: A file containing common English words in order of frequency.data/words.txt
: A file containing many more English words in order of frequency.gui.py
: A web server for the web-based graphical user interface (GUI).gui_files
: A directory of files needed for the graphical user interface (GUI).images
: A directory of images.ok
,proj02.ok
,tests
: Testing files.
You can check out the CATS GUI on Github.
Logistics
The project is worth 20 points. 19 points are assigned for correctness of your final code, and 1 point for submitting Phase 1 by the checkpoint deadline.
You will turn in the following files:
cats.py
You do not need to modify or turn in any other files to complete the project. To submit the project, run the following command:
python3 ok --submit
You will be able to view your submissions on the Ok dashboard.
For the functions that we ask you to complete, there may be some initial code that we provide. If you would rather not use that code, feel free to delete it and start from scratch. You may also add new function definitions as you see fit.
However, please do not modify any other functions. Doing so may result in your code failing our autograder tests. Also, please do not change any function signatures (names, argument order, or number of arguments).
Throughout this project, you should be testing the correctness of your code. It is good practice to test often, so that it is easy to isolate any problems. However, you should not be testing too often, to allow yourself time to think through problems.
We have provided an autograder called ok
to help you
with testing your code and tracking your progress. The first time you run the
autograder, you will be asked to log in with your Ok account using your web
browser. Please do so. Each time you run ok
, it will back up
your work and progress on our servers.
The primary purpose of ok
is to test your implementations.
We recommend that you submit after you finish each problem. Only your last submission will be graded. It is also useful for us to have more backups of your code in case you run into a submission issue. If you forget to submit, your last backup will be automatically converted to a submission.
If you do not want us to record a backup of your work or information about your progress, you can run
python3 ok --localWith this option, no information will be sent to our course servers. If you want to test your code interactively, you can run
python3 ok -q [question number] -iwith the appropriate question number (e.g.
01
) inserted.
This will run the tests for that question until the first one you failed,
then give you a chance to test the functions you wrote interactively.
You can also use the debugging print feature in OK by writing
print("DEBUG:", x)which will produce an output in your terminal without causing OK tests to fail with extra output.
Phase 1: Typing
Phase 1 Hint Video
This video provides some helpful direction for tackling the problems on this phase of CATS.
Problem 1 (1 pt)
Implement choose
. This function selects which paragraph the user will type. It takes three parameters: a list of paragraphs
(strings); a select
function, which returns True
for
paragraphs that can be selected; and a non-negative index k
. The choose
function return's the k
th paragraph for which select
returns True
. If no
such paragraph exists (because k
is too large), then choose
returns the
empty string.
Before writing any code, unlock the tests to verify your understanding of the question.
python3 ok -q 01 -u
Once you are done unlocking, begin implementing your solution. You can check your correctness with:
python3 ok -q 01
Problem 2 (2 pts)
Implement about
, which takes a list of topic
words. It returns a function which
takes a paragraph and returns a boolean indicating whether that paragraph
contains any of the words in topic
.
Once we've implemented about
, we'll be able to pass the returned function to choose
as the select
argument, which will be useful as we continue to implement our typing test.
To be able to make this comparison accurately, you will need to ignore case (that is, assume that uppercase and lowercase letters don't change what word it is) and punctuation in the paragraph. Additionally, only check for exact matches of the words in topic in the paragraph, not substrings. For example, "dogs" is not a match for the word "dog".
Hint: You may use the string utility functions in
utils.py
.
Before writing any code, unlock the tests to verify your understanding of the question.
python3 ok -q 02 -u
Once you are done unlocking, begin implementing your solution. You can check your correctness with:
python3 ok -q 02
Problem 3 (2 pts)
Implement accuracy
, which takes a typed
paragraph and a reference
paragraph. It returns the percentage of words in typed
that exactly match the
corresponding words in reference
. Case and punctuation must match as well.
"Corresponding" here means that two words must occur at the same indices in typed
and reference
βthe first words of both must match, the second words of both must match,
and so on.
A word in this context is any sequence of characters separated from other words by whitespace, so treat "dog;" as all one word.
If typed
is longer than reference
, then the extra words in typed
that have
no corresponding word in reference
are all incorrect.
If both typed
and reference
are empty, then the accuracy is 100.0.
If typed
is empty but reference
is not empty, then the accuracy is zero.
If typed
is not empty but reference
is empty, then the accuracy is zero.
Before writing any code, unlock the tests to verify your understanding of the question.
python3 ok -q 03 -u
Once you are done unlocking, begin implementing your solution. You can check your correctness with:
python3 ok -q 03
π©π½βπ»π¨πΏβπ» Pair programming? Remember to alternate between driver and navigator roles! The driver controls the keyboard; the navigator watches, asks questions, and suggests ideas.
Problem 4 (1 pt)
Implement wpm
, which computes the words per minute, a measure of typing
speed, given a string typed
and the amount of elapsed
time in seconds.
Despite its name, words per minute is not based on the number of words typed,
but instead the number of groups of 5 characters, so that a typing test is not biased by the
length of words. The formula for words per minute is the ratio of the number
of characters (including spaces) typed divided by 5 (a typical word length) to
the elapsed time in minutes.
For example, the string "I am glad!"
contains three words and ten characters
(not including the quotation marks). The words per minute calculation uses 2 as
the number of words typed (because 10 / 5 = 2). If someone typed this string in
30 seconds (half a minute), their speed would be 4 words per minute.
Before writing any code, unlock the tests to verify your understanding of the question.
python3 ok -q 04 -u
Once you are done unlocking, begin implementing your solution. You can check your correctness with:
python3 ok -q 04
Time to test your typing speed! You can use the command line to test your
typing speed on paragraphs about a particular topic. For example, the command
below will load paragraphs about cats or kittens. See the run_typing_test
function for the implementation if you're curious (but it is defined for you).
python3 cats.py -t cats kittens
You can try out the web-based graphical user interface (GUI) using the following
command. (You may have to use Ctrl+C
or Cmd+C
on your terminal to quit the GUI after you close the tab in your browser).
python3 gui.py
To submit your Phase 1 checkpoint type:
python3 ok --submit
You can submit again once you've finished the whole project, and we will score only your latest submission, but please submit at least once before the checkpoint deadline (after finishing at least the Phase 1 questions) to receive credit for the checkpoint.
π¨πΎβπ»π©π»βπ» Pair programming? This is a good time to switch roles! Switching roles makes sure that you both benefit from the learning experience of being in each role.
Phase 2: Autocorrect
In the web-based GUI, there is an autocorrect button, but right now it doesn't do anything. Let's implement automatic correction of typos. Whenever the user presses the space bar, if the last word they typed doesn't match a word in the dictionary but is close to one, then that similar word will be substituted for what they typed.
Phase 2 Hint Video
This video provides some helpful direction for tackling the problems on this phase of CATS.
Problem 5 (2 pts)
Implement autocorrect
, which takes a typed_word
, a list of all valid_words
,
a diff_function
, and a limit
.
If the typed_word
is contained inside the valid_words
list, autocorrect
returns that word.
Otherwise, autocorrect
returns the word from valid_words
that has the lowest difference from the provided typed_word
based on the
diff_function
. However, if the lowest difference between typed_word
and any
of the valid_words
is greater than limit
, then typed_word
is returned
instead.
A diff function takes in three arguments. The first two arguments are the two strings to be
compared (the typed_word
and a word from valid_words
), and the third argument is
the limit
. The output of the diff function, which is a number, represents the
amount of difference between the two strings.
Here is an example of a diff function that computes the minimum of 1 + limit
and
the difference in length between the two input strings:
>>> def length_diff(w1, w2, limit):
... return min(limit + 1, abs(len(w2) - len(w1)))
>>> length_diff('mellow', 'cello', 10)
1
>>> length_diff('hippo', 'hippopotamus', 5)
6
Assume that typed_word
and all elements of valid_words
are lowercase and have
no punctuation.
Important: if multiple strings have the same lowest difference according to
the diff_function
, autocorrect
should return the string that appears first
in valid_words
.
Hint: Try using
max
ormin
with the optionalkey
argument. For some examples of using this argument, check out this link.
Before writing any code, unlock the tests to verify your understanding of the question.
python3 ok -q 05 -u
Once you are done unlocking, begin implementing your solution. You can check your correctness with:
python3 ok -q 05
Problem 6 (2 pts)
Implement feline_flips
, which is a diff function that takes two strings. It
returns the minimum number of characters that must be changed in the start
word in order to transform it into the goal
word. If the strings are not of
equal length, the difference in lengths is added to the total.
Important: You may not use while
or for
statements in your
implementation. Use recursion.
Here are some examples:
>>> big_limit = 10
>>> feline_flips("nice", "rice", big_limit) # Substitute: n -> r
1
>>> feline_flips("range", "rungs", big_limit) # Substitute: a -> u, e -> s
2
>>> feline_flips("pill", "pillage", big_limit) # Don't substitute anything, length difference of 3.
3
>>> feline_flips("roses", "arose", big_limit) # Substitute: r -> a, o -> r, s -> o, e -> s, s -> e
5
>>> feline_flips("rose", "hello", big_limit) # Substitute: r->h, o->e, s->l, e->l, length difference of 1.
5
If the number of characters that must change is greater than limit
, then
feline_flips
should return any number larger than limit
and should minimize
the amount of computation needed to do so.
These two calls to feline_flips
should take about the same amount of time to
evaluate:
>>> limit = 4
>>> feline_flips("roses", "arose", limit) > limit
True
>>> feline_flips("rosesabcdefghijklm", "arosenopqrstuvwxyz", limit) > limit
True
Before writing any code, unlock the tests to verify your understanding of the question.
python3 ok -q 06 -u
Once you are done unlocking, begin implementing your solution. You can check your correctness with:
python3 ok -q 06
Try turning on autocorrect in the GUI. Does it help you type faster? Are the corrections accurate? You should notice that inserting a letter or leaving one out near the beginning of a word is not handled well by this diff function. Let's fix that!
Problem 7 (3 pt)
Implement minimum_mewtations
, which is a diff function that returns the minimum number
of edit operations needed to transform the start
word into the goal
word.
There are three kinds of edit operations:
- Add a letter to
start
, - Remove a letter from
start
, - Substitute a letter in
start
for another.
Each edit operation contributes 1 to the difference between two words.
>>> big_limit = 10
>>> minimum_mewtations("cats", "scat", big_limit) # cats -> scats -> scat
2
>>> minimum_mewtations("purng", "purring", big_limit) # purng -> purrng -> purring
2
>>> minimum_mewtations("ckiteus", "kittens", big_limit) # ckiteus -> kiteus -> kitteus -> kittens
3
We have provided a template of an implementation in cats.py
.
Hint: This is a recursive function with three recursive calls. One of these recursive calls will be similar to the recursive call in
feline_flips
.
You may modify the template however you want or delete it entirely.
If the number of edits required is greater than limit
, then minimum_mewtations
should return any number larger than limit
and should minimize the amount of
computation needed to do so.
These two calls to minimum_mewtations
should take about the same amount of time to
evaluate:
>>> limit = 2
>>> minimum_mewtations("ckiteus", "kittens", limit) > limit
True
>>> minimum_mewtations("ckiteusabcdefghijklm", "kittensnopqrstuvwxyz", limit) > limit
True
Before writing any code, unlock the tests to verify your understanding of the question.
python3 ok -q 07 -u
Once you are done unlocking, begin implementing your solution. You can check your correctness with:
python3 ok -q 07
Try typing again. Are the corrections more accurate?
python3 gui.py
π¨πΎβπ»π©π»βπ» Pair programming? Celebrate, take a break, and switch roles!
(Optional) Extension: final diff (0pt)
You may optionally design your own diff function called
final_diff
. Here are some ideas for making even more accurate corrections:
- Take into account which additions and deletions are more likely than others. For example, it's much more likely that you'll accidentally leave out a letter if it appears twice in a row.
- Treat two adjacent letters that have swapped positions as one change, not two.
- Try to incorporate common misspellings
You can also set the limit you'd like your diff function to use by changing the value of the variable FINAL_DIFF_LIMIT
in cats.py
.
You can check your final_diff
's success rate by running:
python3 score.py
If you don't know where to start, try copy-pasting your code for feline_flips
and minimum_mewtations
into final_diff
and scoring them. Looking at the typos they accidentally fixed might give you some ideas!
Phase 3: Multiplayer
Typing is more fun with friends! You'll now implement multiplayer functionality,
so that when you run gui.py
on your computer, it connects to the
course server at cats.cs61a.org and looks for someone else to race against.
To race against a friend, 5 different programs will be running:
- Your GUI, which is a program that handles all the text coloring and display in your web browser.
- Your
gui.py
, which is a web server that communicates with your GUI using the code you wrote incats.py
. - Your opponent's
gui.py
. - Your opponent's GUI.
- The CS 61A multiplayer server, which matches players together and passes messages around.
When you type, your GUI sends what you have typed to your gui.py
server, which
computes how much progress you have made and returns a progress update. It also
sends a progress update to the multiplayer server, so that your opponent's GUI can
display it.
Meanwhile, your GUI display is always trying to keep current by asking for
progress updates from gui.py
, which in turn requests that info from the
multiplayer server.
Each player has an id
number that is used by the server to track typing
progress.
Phase 3 Hint Video
This video provides some helpful direction for tackling the problems on this phase of CATS.
Coming soon!
Problem 8 (2 pts)
Implement report_progress
, which is called every time the user finishes typing
a word. It takes a list of the words sofar
, a list of the words in the
prompt
, the user's user_id
, and a send
function that is used to send a progress
report to the multiplayer server. There will never be more words in
sofar
than in prompt
.
Your progress is a ratio of the words in the prompt
that you have typed
correctly, up to the first incorrect word, divided by the number of prompt
words. For example, this example has a progress of 0.25
:
report_progress(["Hello", "ths", "is"], ["Hello", "this", "is", "wrong"], ...)
Your report_progress
function should do two things: send a message to the multiplayer server and return the progress of the player with user_id
.
You can send a message to the multiplayer server by calling the send
function on a two-element dictionary containing the keys 'id'
and 'progress'
. You should then return the player's progress, which is the ratio of words you computed.
Hint: See the dictionary below for an example of a potential input into the
send
function. This dictionary represents a player withuser_id
1 andprogress
0.6.
{'id': 1, 'progress': 0.6}
Before writing any code, unlock the tests to verify your understanding of the question.
python3 ok -q 08 -u
Once you are done unlocking, begin implementing your solution. You can check your correctness with:
python3 ok -q 08
Problem 9 (2 pts)
Implement time_per_word
, which takes in times_per_player
, a list of lists
for each player with timestamps indicating when each player finished typing each
word. It also takes in a list words
. It returns a game
with the given
information.
A game
is a data abstraction that has a list of words
and times
. The
times
are stored as a list of lists of how long it took each player to type
each word. times[i][j]
indicates how long it took player i
to type word j
.
Timestamps are cumulative and always increasing, while the values in times
are differences between consecutive timestamps for each player.
Here's an example: If
times_per_player = [[1, 3, 5], [2, 5, 6]]
, the correspondingtimes
attribute of thegame
would be[[2,2], [3, 1]]
. This is because the differences in timestamps are(3-1)
,(5-3)
for the first player and(5-2)
,(6-5)
for the second player. The first value of each list withintimes_per_player
represents the initial starting time for each player.
Be sure to use the game
constructor when returning a game
, rather than assuming a particular data format. Read the definitions for the game
constructor and selectors in cats.py
to learn more about how the data abstraction is implemented.
Before writing any code, unlock the tests to verify your understanding of the question.
python3 ok -q 09 -u
Once you are done unlocking, begin implementing your solution. You can check your correctness with:
python3 ok -q 09
π©π»βπ»π¨πΏβπ» Pair programming? We suggest switching roles now, if you haven't recently. Almost done!
Problem 10 (2 pts)
Implement fastest_words
, which returns which words each player typed fastest.
This function is called once both players have finished typing. It takes in a game
.
Specifically, the fastest_words
function returns a list of lists of words, one list for each
player, and within each list the words they typed the fastest (against all the other players). In the case of a tie, consider the earliest player in the list (the smallest player index) to be the one who typed it the fastest.
For example consider the following game with the words 'Just', 'have', and 'fun'. Player 0 typed 'fun' the fastest (3 seconds), Player 1 typed 'Just' the fastest (4 seconds), and they tied on the word 'have' (both took 1 second) so we consider to Player 0 to be the fastest, because they are the earliest player in the list.
>>> player_0 = [5, 1, 3]
>>> player_1 = [4, 1, 6]
>>> fastest_words(game(['Just', 'have', 'fun'], [player_0, player_1]))
[['have', 'fun'], ['Just']]
The game
argument is a game
data abstraction, like the one returned in
Problem 9. You can access words in the game
with the selector word_at
, which
takes in a game
and the word_index
(an integer). With word_at
you can
access the time it took any player to type any word using time
.
Be sure to use the accessor functions for the game
data abstraction, rather
than assuming a particular data format.
Before writing any code, unlock the tests to verify your understanding of the question.
python3 ok -q 10 -u
Once you are done unlocking, begin implementing your solution. You can check your correctness with:
python3 ok -q 10
Congratulations! Now you can play against other students in the course. Set
enable_multiplayer
to True
near the bottom of cats.py
and type swiftly!
python3 gui.py
At this point, run the entire autograder to see if there are any tests that don't pass.
python3 ok
Once you are satisfied, submit to Ok to complete the project.
python3 ok --submit
If you have a partner, make sure to add them to the submission on okpy.org.
Check to make sure that you did all the problems by running
python3 ok --score