Parallel creation of complex dataframes Question: The below code seems to have some issues. The aim would be to append each result of new_df() to some list, e.g. out. import pandas as pd import random import time from multiprocessing import Pool def new_df(rows=10000): # proxy for complex dataframe temp = pd.DataFrame({‘a’: [”.join(chr(random.randint(65,122)) for _ in …
How to properly close and unlink shared memory of multiprocessing? Question: I’m trying to use the multiprocessing module and to add 1 to the shared memory in each process. But, I see the errors when running the following code. Can anyone tell how to close and unlink the shared momery? Here is the code. from …
urllib3 connectionpool – Connection pool is full, discarding connection Question: Does seeing the urllib3.connectionpool WARNING – Connection pool is full, discarding connection mean that I am effectively loosing data (because of lost connection) OR Does it mean that connection is dropped (because pool is full); however, the same connection will be re-tried later on when …
Python HTTPConnectionPool Failed to establish a new connection: [Errno 11004] getaddrinfo failed Question: I was wondering if my requests is stopped by the website and I need to set a proxy.I first try to close the http’s connection ,bu I failed.I also try to test my code but now it seems no outputs.Mybe I use …
Pool within a Class in Python Question: I would like to use Pool within a class, but there seems to be a problem. My code is long, I created a small-demo variant to illustrated the problem. It would be great if you can give me a variant of the code below that works. from multiprocessing …
python multiprocess.Pool show results in order in stdout Question: In multiprocessing.Pool I am trying to show my prints in the the same order. from multiprocessing import Pool import time def func(arg): time.sleep(0.001) print(arg, end=” “) proc_pool = Pool(4) proc_pool.map(func, range(30)) The output is: 0 1 8 9 10 11 14 15 6 7 16 17 …
Passing multiple parameters to pool.map() function in Python Question: I need some way to use a function within pool.map() that accepts more than one parameter. As per my understanding, the target function of pool.map() can only have one iterable as a parameter but is there a way that I can pass other parameters in as …
multiprocessing.Pool() slower than just using ordinary functions Question: (This question is about how to make multiprocessing.Pool() run code faster. I finally solved it, and the final solution can be found at the bottom of the post.) Original Question: I’m trying to use Python to compare a word with many other words in a list and …
How does the callback function work in multiprocessing map_async? Question: It cost me a whole night to debug my code, and I finally found this tricky problem. Please take a look at the code below. from multiprocessing import Pool def myfunc(x): return [i for i in range(x)] pool=Pool() A=[] r = pool.map_async(myfunc, (1,2), callback=A.extend) r.wait() …
Using python multiprocessing Pool in the terminal and in code modules for Django or Flask Question: When using multiprocessing.Pool in python with the following code, there is some bizarre behavior. from multiprocessing import Pool p = Pool(3) def f(x): return x threads = [p.apply_async(f, [i]) for i in range(20)] for t in threads: try: print(t.get(timeout=1)) …
