datar

A Grammar of Data Manipulation in python

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datar is a re-imagining of APIs of data manipulation libraries in python (currently only pandas supported) so that you can manipulate your data with it like with dplyr in R.

datar is an in-depth port of tidyverse packages, such as dplyr, tidyr, forcats and tibble, as well as some functions from base R.

Installation

pip install -U datar

# install pdtypes support
pip install -U datar[pdtypes]

# install dependencies for modin as backend
pip install -U datar[modin]
# you may also need to install dependencies for modin engines
# pip install -U modin[ray]

Example usage

from datar import f
from datar.dplyr import mutate, filter, if_else
from datar.tibble import tibble
# or
# from datar.all import f, mutate, filter, if_else, tibble

df = tibble(
    x=range(4),  # or f[:4]
    y=['zero', 'one', 'two', 'three']
)
df >> mutate(z=f.x)
"""# output
        x        y       z
  <int64> <object> <int64>
0       0     zero       0
1       1      one       1
2       2      two       2
3       3    three       3
"""

df >> mutate(z=if_else(f.x>1, 1, 0))
"""# output:
        x        y       z
  <int64> <object> <int64>
0       0     zero       0
1       1      one       0
2       2      two       1
3       3    three       1
"""

df >> filter(f.x>1)
"""# output:
        x        y
  <int64> <object>
0       2      two
1       3    three
"""

df >> mutate(z=if_else(f.x>1, 1, 0)) >> filter(f.z==1)
"""# output:
        x        y       z
  <int64> <object> <int64>
0       2      two       1
1       3    three       1
"""

# works with plotnine
# example grabbed from https://github.com/has2k1/plydata
import numpy
from datar.base import sin, pi
from plotnine import ggplot, aes, geom_line, theme_classic

df = tibble(x=numpy.linspace(0, 2*pi, 500))
(df >>
  mutate(y=sin(f.x), sign=if_else(f.y>=0, "positive", "negative")) >>
  ggplot(aes(x='x', y='y')) +
  theme_classic() +
  geom_line(aes(color='sign'), size=1.2))

example

# easy to integrate with other libraries
# for example: klib
import klib
from datar.core.factory import verb_factory
from datar.datasets import iris
from datar.dplyr import pull

dist_plot = verb_factory(func=klib.dist_plot)
iris >> pull(f.Sepal_Length) >> dist_plot()

example

See also some advanced examples from my answers on StackOverflow: