Forked from yong27/apply_df_by_multiprocessing.py
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September 15, 2015 14:41
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pandas DataFrame apply multiprocessing
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import multiprocessing | |
import pandas as pd | |
import numpy as np | |
def _apply_df(args): | |
df, func, kwargs = args | |
return df.apply(func, **kwargs) | |
def apply_by_multiprocessing(df, func, **kwargs): | |
workers = kwargs.pop('workers') | |
pool = multiprocessing.Pool(processes=workers) | |
result = pool.map(_apply_df, [(d, func, kwargs) | |
for d in np.array_split(df, workers)]) | |
pool.close() | |
return pd.concat(list(result)) | |
def square(x): | |
return x**x | |
if __name__ == '__main__': | |
df = pd.DataFrame({'a':range(10), 'b':range(10)}) | |
apply_by_multiprocessing(df, square, axis=1, workers=4) | |
## run by 4 processors | |
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