Created
February 8, 2021 13:57
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The idea here is to asynchronously process chunk of data by pushing it into a multiprocessing pool queue. Each process in pool will work on the task, and return the result. Note, it is important to create the Pool inside the __main__ block. That is
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import pandas as pd | |
import multiprocessing as mp | |
LARGE_FILE = "D:\\my_large_file.txt" | |
CHUNKSIZE = 100000 # processing 100,000 rows at a time | |
def process_frame(df): | |
# process data frame | |
return len(df) | |
if __name__ == '__main__': | |
reader = pd.read_table(LARGE_FILE, chunksize=CHUNKSIZE) | |
pool = mp.Pool(4) # use 4 processes | |
funclist = [] | |
for df in reader: | |
# process each data frame | |
f = pool.apply_async(process_frame,[df]) | |
funclist.append(f) | |
result = 0 | |
for f in funclist: | |
result += f.get(timeout=10) # timeout in 10 seconds | |
print "There are %d rows of data"%(result) |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
import pandas as pd | |
LARGE_FILE = "D:\\my_large_file.txt" | |
CHUNKSIZE = 100000 # processing 100,000 rows at a time | |
def process_frame(df): | |
# process data frame | |
return len(df) | |
if __name__ == '__main__': | |
reader = pd.read_table(LARGE_FILE, chunksize=CHUNKSIZE) | |
result = 0 | |
for df in reader: | |
# process each data frame | |
result += process_frame(df) | |
print "There are %d rows of data"%(result) |
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