dabeaz-course / python-mastery Goto Github PK

From Exercise 7.1 (b):

Note: This part doesn't involve a lot of code, but there are a lot of low-level fiddly bits. The solution will look almost the same as for Exercise 6.6.

There is no Exercise 6.6. The previous exercise was 6.5, not 6.6.

Hi David, first of all thanks for providing this course, it’s been great so far (currently chapter 6).

I just wanted to share some comments/questions that came up while looking at the slides:

1. In the slide 3-77 there is an extra handler in formatter = TextTableFormatter(handler)

2. The MRO of 4-21 doesn't match the hierarchy previously defined

   • If E was intended, I think it should be (__main__.E, __main__.C, __main__.A, __main__.D, __main__.B, object)
   • If D was indeed intended, I think it should be (__main__.D, __main__.B, object)

3. In 5-14 the following is mentioned:

   Important: there are no type signatures or other details to help people reading your code. If you can help clarify, that's usually good.

   Type hints although not enforced by python exist so it can help (they’re even mentioned on the next slide), so imo the sentence may be confusing

The doc says locale.getencoding() is used as the default. On Windows, it's the ANSI codepage.

When running structure.py from excercise 7_6 I am getting an error:

 line 69, in <listcomp>
    cls._fields = tuple([v.name for v in validators])
AttributeError: 'String' object has no attribute 'name'

This is a not modified file, straight from repository, so I am not sure why this happens?

Welcome!

Use discussions to:

• Ask questions about the course
• Share ideas and interesting resources.
• Engage with other members who are working on the course material.

I'm not always available to answer detailed course questions, but perhaps discussions can be used as an ongoing knowledge base for the course.

Cheers,
Dave

Originally posted by @dabeaz in #1

The memory should drop quite a bit.

in Exercises/ex2_6.md seems like a non sequitur, because there was no previous tracemalloc.get_traced_memory() call in the same exercise.

WHERE CAN I GET JAVASCRIPT LIKE THIS PLEASE?

After reassignment of a = [4, 5, 6], b still pointing to [1, 2, 3] should have a memory ref = 2 but slide says ref = 1.

In the example for context manager.

Shouldn't the following:

if type:
    print('An exception occurred')

be instead

if ty:
    print('An exception occurred')

Thank you very very much for this material. It's amazing! I'm super grateful for it.

I think I spotted a small error in the code on slide 2-44:

-for n in squares:
+for n in squares([1, 2, 3, 4, 5]):

I think the squares should be called to be effective.

Thank you again for sharing your knowledge.

In slide I.II it is mentioned:

There are no block comments in Python (e.g., /* ... */).

While triple quotes are technically strings not comments, they could serve the same purpose as block comments? do you think this is worth mentioning?

Thank you

On page 98 (2-27):

>>> allrices['HPE']
34.23
>>> allprices['F']
51.1
>>>

Should be >>> allprices['HPE']

In PythonMastery.pdf page 2-6, the sentence An unordered set of values indexed by "keys" should be changed, because dictionaries are ordered since Python 3.6

Even if you don't include an implementation, you should include the correct results for the exercise prompt.

How many bus routes exist in Chicago?

'Number of unique routes:'
181

How many people rode the number 22 bus on February 2, 2011? What about any route on any date of your choosing?

'Number of route 22 riders on 02/02/2011:'
[Row(route='22', date='02/02/2011', daytype='W', rides=5055)]

What is the total number of rides taken on each bus route?

'Most popular routes:'
[('79', 133796763), ('9', 117923787), ('49', 95915008)]

What five bus routes had the greatest ten-year increase in ridership from 2001 to 2011?

'Route with most increase in passengers between 2001 and 2011:'
[('15', 2732209),
('147', 2107910),
('66', 1612958),
('12', 1612067),
('14', 1351308)]

The Discussion at the end of Exercise 7.2 says the following:

Writing robust decorators is often a lot harder than it looks. Recommended reading:

However, there's no recommendation. Perhaps it was omitted accidentally?

The slide entitled "Function Error Checking" appears twice, once as slide 5-41 and then again as slide 5-42.

The slide states:

Variable names follow same rules as C
[A-Za-z_][A-Za-z0-9_]*

However, since Python 3.0 variable names can also contain non-non-ASCII letters (such as accented characters, Cyrillic, Greek, Kanji, etc.).

https://docs.python.org/3/reference/lexical_analysis.html#identifiers

https://peps.python.org/pep-3131/

Thanks for the helpful course.
Small issue I ran into in exercise 2_5 in:

import collections
class RideData(collections.Sequence):

Gave me an attribute error running python 3.11 on a windows machine.
This is due to:

`DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated 
since Python 3.3, and in 3.10 it will stop working` 

This issue provides more detail.
adding

'import collections.abc'  

and

'class RideData(collections.abc.Sequence)'

Solves this

The relative path is written as ../../Data/portfolio.dat, but unfortunately this results in a FileNotFoundError: [Errno 2] No such file or directory: '../../Data/portfolio.dat'. In my solution I had to use the pathlib library to construct a path as such:

root_dir = Path(__file__).resolve().parent.parent.parent
relative_dir = 'Data/portfolio.dat'
filename = root_dir / relative_dir
f = open(filename, 'r')```

I suggest adding the topics tutorial, python-tutorial in the About section. Thanks for your project.

Your challenge is to modify the RideData class, however to show the expected result you use readrides.read_rides_as_columns() as an example and this method does not currently return a RideData object...

Should this method also be modified to return a RideData object? Otherwise modifying RideData will have no affect on the output of readrides.read_rides_as_columns() ?

Shouldn't the following line:

threading.Thread(target=func, args=(2, 3, fut).start()

be instead

threading.Thread(target=func, args=(2, 3, fut)).start()

Thank you so much for this! Its great! Would be awesome if we can have one for C++ too :)

minegrub/assets/splashes.txt

Originally posted by @Patish11 in Lxtharia/minegrub-theme#21 (comment)

Instead of

for r in rows:

it should be

for r in range(rows):

In the last challenge of this exercise, we are asked to eliminate the need for providing names to typedproperty. I can't get this to work with the closure template provided. Can I get some more hints or just the solution, as I have been banging my head against this problem for a couple of hours now? I realize that __set_name__ is called under the hood when assigning properties to the class, and this was pretty clear in the valiidate.py exercise. I'm unsure how this works when extending the class with these typedproperty methods. Thanks for the help.

The handler is the same object isn't it?

Should the sentence:

Notice how various steps of the algorithm are deferred to a separate handler object

Be phrased:

Notice how various steps of the algorithm are deferred to a separate (method|function) of the handler object