datar VS polars

datar does not only mimic the piping syntax, but follows the API design from dplyr as much as possible, and is tested with its test cases.

df = tibble( x=range(4), y=['zero', 'one', 'two', 'three'] ) df >> mutate(z=f.x) """# output x y z 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 0 0 zero 0 1 1 one 0 2 2 two 1 3 3 three 1 """ df >> filter(f.x>1) """# output: x y 0 2 two 1 3 three """ df >> mutate(z=if_else(f.x>1, 1, 0)) >> filter(f.z==1) """# output: x y z 0 2 two 1 1 3 three 1 """ ``` Works with plotnine ```python 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)) ```  Easy to integrate with other libraries ```python import klib from pipda import register_verb from datar.datasets import iris from datar.dplyr import pull dist_plot = register_verb(func=klib.dist_plot) iris >> pull(f.Sepal_Length) >> dist_plot() ```  For more detailed and advanced usage, see https://pwwang.github.io/datar/

This is because 0.1 is in actuality the floating point value value 0.1000000000000000055511151231257827021181583404541015625, and thus 1 divided by it is ever so slightly smaller than 10. Nevertheless, fpround(1 / fpround(1 / 10)) = 10 exactly.

I found out about this recently because in Polars I defined a // b for floats to be (a / b).floor(), which does return 10 for this computation. Since Python's correctly-rounded division is rather expensive, I chose to stick to this (more context: https://github.com/pola-rs/polars/issues/14596#issuecomment-...).

https://github.com/pola-rs/polars/releases/tag/py-0.19.0

That turned out to be related to pola-rs/polars#11912, and this linked comment provided a deceptively simple solution - use PARSE_DECLTYPES when creating the connection: