Sequential chaining of itertools operators Question: I’m looking for a nice way to sequentially combine two itertools operators. As an example, suppose we want to select numbers from a generator sequence less than a threshold, after having gotten past that threshold. For a threshold of 12000, these would correspond to it.takewhile(lambda x: x<12000) and it.takewhile(lambda …
Python generator vs iterator Question: So I have custom iterator which represents as a class CustomIterator below. The last print shows a size of all data which it uses when gets one char from some string. 1170 bytes. class CustomIterator: def __init__(self, collection: str): self.__position = 0 self.__collection = collection def __iter__(self): return self def …
What is the difference between exhausting a generator using "for i in generator" and next(generator) Question: I want to learn how to use the return value of a generator (but this not what I’m concerned with now). After searching, they said that I can get the return value from StopIteration when the generator is exhausted, …
How does generator * / splat unpacking work? Question: Let’s say I have some function f that will accept a variable number of arguments: def f(*args): for a in args: print(a) Below I call on this function three ways: Case 1: Passing in a generator expression without parenthesis: f(l for l in range(5)) >>> <generator …
How to DRY up this psycopg connection pool boilerplate code with a reusable async function or generator? Question: I’m using psycopg to connect to a PostgreSQL database using a connection pool. It works great, but any function that needs to run SQL in a transaction gets three extra layers of nesting: /app/db.py from os import …
Weird behaviour of a generator function while converting it to a list Question: I am trying to get every state of a list while it is being sorted for a visualization. So with bubbleSort algorithm i made a generator function : def bubbleSort(arr): n = len(arr) yield arr # yielding original state for i in …
When using Apache Beam Python with GCP Dataflow, does it matter if you materialize the results of GroupByKey? Question: When using Apache Beam Python with GCP Dataflow, is there a downside to materializing the results of GroupByKey, say, to count the number of elements. For example: def consume_group_by_key(element): season, fruits = element for fruit in …
Variable in generator function shadows name from outer scope Question: I recently started to teach myself Python and currently work on generator functions. Here, I encountered a "scoping" issue with variable names inside of the generator shadowing names in outer scope. I did some research on this but could not come up with an explanation. …
Return several values inside for loop Question: I have a function that must return several values using a for loop. I do not wish to store the values inside a list or a dict. Because of the use of the return, I only get the first value. How can I return all values successively? I …
Random dont chose 8 character words Question: I used random module in my ptoject. Im not a programmer, but i need to do a script which will create a randomized database from another database. In my case, I need the script to select random words lined up in a column from the "wordlist.txt" file, and …
