swifter

A package which efficiently applies any function to a pandas dataframe or series in the fastest available manner.

To know about latest improvements, please check changelog.

Installation:

$ pip install -U pandas # upgrade pandas
$ pip install swifter # first time installation

$ pip install -U swifter # upgrade to latest version if already installed

alternatively, to install on Anaconda:

conda install -c conda-forge swifter

...after installing, import swifter into your code along with pandas using:

import pandas as pd
import swifter

Easy to use

df = pd.DataFrame({'x': [1, 2, 3, 4], 'y': [5, 6, 7, 8]})

# runs on single core
df['x2'] = df['x'].apply(lambda x: x**2)
# runs on multiple cores
df['x2'] = df['x'].swifter.apply(lambda x: x**2)

# use swifter apply on whole dataframe
df['agg'] = df.swifter.apply(lambda x: x.sum() - x.min())

# use swifter apply on specific columns
df['outCol'] = df[['inCol1', 'inCol2']].swifter.apply(my_func)
df['outCol'] = df[['inCol1', 'inCol2', 'inCol3']].swifter.apply(my_func,
             positional_arg, keyword_arg=keyword_argval)

Further documentations on swifter is available here.

Check out the examples notebook, along with the speed benchmark notebook

Vectorizes your function, when possible

When vectorization is not possible, automatically decides which is faster: to use dask parallel processing or a simple pandas apply

Notes