dougdrums posted:

BSON is kinda silly. Auditing mongoDB databases is fun (because you can charge more). My DB class in college was 90% mongoDB and also 100% a waste of time.

Wallet posted:

The best way to store a date? Clearly a string, except when you feel like using an ISODate. Want to record whether something is supposed to be on or off? Use a string and set the value to "on" or "off", obviously.

SurgicalOntologist posted:

You are re-creating the column 'combined' at every iteration of the loop, essentially resetting it. Try this:

Python code:

df_maps['combined'] = ''
for i, row in df_maps.iterrows():
    df_maps.at[i, 'combined'] = row.html.replace('$name', row.name)

or

Python code:

def insert_name(row):
    return row.html.replace('$name', row.name)


df_maps['combined'] = df_maps.apply(insert_name)

(you may need to play around with the kwargs to apply to get that to work)

cinci zoo sniper posted:

First example works just fine for me with strict mypy, so I'm confused what are you doing there. What Python and mypy versions are you using?

cinci zoo sniper posted:

Also you should replace that for block with pos += users, or pos += [....] alltogether.

Second example is not sufficient - what are you typing and how?

Dr Subterfuge posted:

unpacked robinhood posted:

That's python 3.7 and mypy 0.641

Replacing the for block with pos.extend(users) seems to do the trick

unpacked robinhood posted:

I should have included the function signature in my second question:

Python code:

def find_resources(self, another_list: List[str])-> Optional[str]:
...
	a_list = list(filter(lambda x:  urlparse(x['name']).path == '/a/normal/path', another_list))
...

unpacked robinhood posted:

I'm trying to have mypy check my type hints, and..I think I've no idea what I'm doing.

This runs fine:

Python code:

pos: List[Dict] = []
...
if 'users' in a_dict.keys():
   # creating a list of dicts
    users = [{'type': 'user','lng': x['location']['x'], 'lat':x['location']['y']} for x in a_dict['users']]
    for lt in users:
        pos.append(lt)

code:

File.py:83: error: Incompatible types in assignment (expression has type "Dict[str, Any]", variable has type "List[Dict[str, Any]]")
File.py:84: error: Argument 1 to "append" of "list" has incompatible type "List[Dict[str, Any]]"; expected "Dict[Any, Any]"

I'm adding dictionnaries as individual values in a list, what am I missing ?

quote:

e: another troublesome one:

Python code:

a_list = list(filter(lambda x:  urlparse(x['name']).path == '/a/normal/path', another_list))

code:

error: Invalid index type "str" for "str"; expected type "Union[int, slice]"

QuarkJets posted:

This discussion is reminding me that I hate lambda and how it always makes code look super ugly. Does anyone else hate lambda?

QuarkJets posted:

This discussion is reminding me that I hate lambda and how it always makes code look super ugly. Does anyone else hate lambda?

baka kaba posted:

Python's variables are basically key/value pairs in a local dictionary, so when you assign butt = 69 it's adding an entry to that. If you try to reference a variable before you assign it, it's like looking up a key that doesn't exist (+= is basically 3 operations - read, increment, write)

The global keyword basically makes that global value accessible so you can look it up in the global dictionary, or however it works under the hood. You can access it, anyway

(hope the dictionary stuff is still true...)

LochNessMonster posted:

Thanks for explaining. I can’t believe I’ve never ran into this issue before though.

On Stack Overflow it’s mentioned multiple times that this is not a pythonic way to do things. Any ideas on how I could avoid this?

LochNessMonster posted:

Thanks for all the great examples.

Before posting I did try passing curr_freq to the function but my program then stopped at the 1st value of the 2nd pass of the input file. Made me think that the value for curr_freq was reset to 0 and then the first value of the 2nd pass would always be the first duplicate.

I'm not really sure why it does that. I expected the variable to be updated each time the function is executed, but apparently each iteration of the function takes the (global) curr_freq = 0 as a start again. So just passing it to the function is not enough. While typing this I figured out how to solve it. It's just as dirty as the rest of the code but it does the job.

Python code:

while duplicate_freq == False:
    curr_freq = run_freq_calc(curr_freq)

Now it's time to improve/learn from all the stuff you guys posted and apply it to the next challenges.

Fluue posted:

This is more of a software-design question and I'm having trouble remembering the "pythonic" or "preferred" way of doing it so its more testable:

I'm using a Python JIRA library to interact with the JIRA Service Desk (help desk sort of thing).

There's a requirement to support different "support ticket" backends, so I figured I would create TicketManager class that wraps around the JIRA Library to give a standard interface for any of the functionality I plan on using.

I also have to work with individual support tickets, so I created a Ticket library that takes in a JIRA "issue" object and I can call methods on that.

So I have:

code:

class TicketManager:

    def __init__(self):
        self.client = Jira()

    def get_ticket(self, ticket_id):
        # returns 'issue` instance from Jira class
        self.client.get_issue(ticket_id)

    def some_other_action(self):
        # whatever

class Ticket:
    def __init__(self, issue):
        self.ticket = issue

    def get_process_owners(self):
        # would have some more complex implementation here, not just a getter
        return self.issue.managers

    def submit_for_changes(self):
        pass


### my_implementation.py
def handle_issue_update(ticket_id):
    manager = TicketManager()
    ticket = Ticket(issue=manager.get_get_ticket(ticket_id)
    owners = ticket.get_process_owners()
    ...
   ticket.submit_for_changes()

Am I on the right track with this? I have trouble converting from classic OOP from Java/C# to Python's way of doing classes.

Gothmog1065 posted:

If I initialize a variable within a class method, does it have to use the self prefix?

code:

class Class(object):
    def __init__(self, varA, varB):
        self.varA = varA
        self.varB = varB
        
    self.res_str = ""
    num = 0

    def work_on_vars():
        num = self.varA + self.varB

        if num < 2:
            self.res_str = "This particular number is less than 2!
        else: 
            print "Do something else"

Therefore all of the instances can work on res_str, but in question, num should be a local variable that can't be called from outside of the specific function/class, correct? I can't do something like this:

code:

foo = Class(1,3)
bar = Class(3,5)
print foo.num
print bar.num

SurgicalOntologist posted:

I'm doing a bunch of computations and saving them to a database. The following function is supposed to be committing to the database every 100 results (based on the variable commit_interval), and stopping after 10,000 (the value of total). But I'm not getting 10,000 results on each backtest_set, instead I'm getting 9,900. Can anyone spot the error? Am I making a basic off-by-one -ish mistake or do I have some weird race condition? I can't figure it out. Here's the code.

Python code:

    results = []
    for i, result in enumerate(tqdm(
            backtest_set.run(),
            unit='entry', desc='Backtesting', total=total, unit_scale=True,
    ), 1):
        results.append(dict(backtest_id=backtest_set.id, fantasy_points_hundredths=result))
        if not i % commit_interval or i == total:
            db.execute(models.BacktestResult.__table__.insert(), results)
            db.commit()
            results = []
        if i == total:
            break

Any ideas?

The actual work is here is done inside the generator function backtest_set.run(). And if you haven't seen it before, tqmd is just a progress bar library (a pretty great one), as I'm using it just wraps an iterable. The only other things there are my models and sqlalchemy session db.