Python tip of the week

[alastair]

Some suggestions of tips to email people about how to do things better in python

• Use python 3
• How to do stylechecks using your favourite editor
• Use time.monotonic() to count how long something takes
• Use concurrent.futures for multiprocessing
  [ffont] I have a utility class for this in pymtg based in concurrent.futures. we can talk about that. I guess I could do this tip
• Use sets or dictionary keys to check membership when in loops
• collections.defaultdict
• collections.Counter
• os.path.join or Pathlib instead of concatenating paths with + '/' +
• Argument parsing / Fire
• CSV module instead of constructing by hand
• enumerate
• dict.items
• zip
• sorting

[LPorcaro]

I like to use pyflakes for checking my code while testing
https://pypi.org/project/pyflakes/
Maybe it can be in the same tip with stylechecks (even if it is not properly a stylecheck)

[jordipons]

student_tuples = [ ('john', 'A', 15), ('jane', 'B', 12), ('dave', 'B', 10), ]
sorted(student_tuples, key=lambda student: student[2]) # sort by age
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

Sort with the lambda function.
https://wiki.python.org/moin/HowTo/Sorting

[alastair]

sorting is a great item! especially using lambdas or the operator module for the key parameter.

[xavierfav]

More suggestions:

• *args and **kwargs
• Avoid running out of memory with Generators
• for/else
• Classes
• Reduce RAM usage & make attribute accesses faster with __slots__ (https://habr.com/en/post/458518/)
• Variable scope

[wuaalb]

• conda package/environment manager
• collections.OrderedDict (note dict ordered in CPython 3.6 and dict ordered in 3.7 language)
• f-strings (3.6+)
• itertools (e.g. example below)
• numba jit compiler
• pysoundfile (libsndfile wrapper) for audio file i/o
• resampy for resampling
• pytoml / TOML for config files
• logging

example of splitting note sequence into phrases using itertools.groupby:

>>> import itertools
>>> notes = ['sil', 'g', 'g', 'd', 'd', 'e', 'e', 'd', 'sil', 'c', 'c', 'b', 'b', 'a', 'a', 'g', 'sil']
>>> phrases = []
>>> for is_sil, group in itertools.groupby(notes, key=lambda note: note == 'sil'):
...     if not is_sil:
...         phrases.append(list(group))
... 
>>> print(phrases)
[['g', 'g', 'd', 'd', 'e', 'e', 'd'], ['c', 'c', 'b', 'b', 'a', 'a', 'g']]