summarize

[samukweku]

Brief Description

I would like to propose a summarize function, similar to dplyr's summarise function and pandas' agg function, but for grouping operations, and more flexible

Example API

df.summarize(y='sum',n=lambda df: df.nth(1), by='x')

# summarize on multiple columns
df.summarize((['a','b','c'], 'sum'), by = 'x')

# replicate dplyr's across
# https://stackoverflow.com/q/63200530/7175713
# select_columns syntax can fit in nicely here
mtcars.summarize(("*t", "mean"), ("*p", "sum"), by='cyl')