import sys
import tidypolars as tp
sys.version
# '3.9.7 (default, Sep 16 2021, 13:09:58) \n[GCC 7.5.0]'
tp.__version__
# '0.2.1'
## error
df = tp.Tibble(x1 = range(3), x2 = range(3), y=range(3), z = range(3))
df.drop([tp.starts_with('x'), 'z'])
df.drop()
`
---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
/tmp/ipykernel_12815/866601321.py in <module>
----> 1 df.drop(tp.starts_with('x'))

~/miniconda3/envs/py39/lib/python3.9/site-packages/polars/eager/frame.py in drop(self, name)
   2253             return df
   2254 
-> 2255         return wrap_df(self._df.drop(name))
   2256 
   2257     def drop_in_place(self, name: str) -> "pl.Series":

RuntimeError: Any(NotFound("^x.*$"))
`

import tidypolars as tp
from tidypolars import col, desc
import sys
sys.version
# '3.10.0 | packaged by conda-forge | (default, Oct 12 2021, 21:24:52) [GCC 9.4.0]'
tp.__version__
# '0.2.1'
df = tp.Tibble({'x': ['a', 'a', 'b'], 'y': range(3)})
df.arrange('x', 'y')
`
---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
~/miniconda3/envs/py310/lib/python3.10/site-packages/polars/eager/frame.py in __getattr__(self, item)
    882         try:
--> 883             return pl.eager.series.wrap_s(self._df.column(item))
    884         except RuntimeError:

RuntimeError: Any(NotFound("arrange"))

During handling of the above exception, another exception occurred:

AttributeError                            Traceback (most recent call last)
/tmp/ipykernel_21110/1194586334.py in <module>
----> 1 df.arrange('x', 'y')

~/miniconda3/envs/py310/lib/python3.10/site-packages/polars/eager/frame.py in __getattr__(self, item)
    883             return pl.eager.series.wrap_s(self._df.column(item))
    884         except RuntimeError:
--> 885             raise AttributeError(f"{item} not found")
    886 
    887     def __iter__(self) -> Iterator[Any]:

AttributeError: arrange not found
`

Hi Mark, thanks for putting this package together. It looks very cool.

I'm having a tough time getting the motivating examples to work, though. For example, the following triggers an error:

import tidypolars as tp
from tidypolars import col, desc

df = tp.Tibble(x = range(3), y = range(3, 6), z = ['a', 'a', 'b'])

df.filter(col('x') < 2).arrange(desc('z'), 'x')

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Untitled-1 in <cell line: 1>()
----> <a href='untitled:Untitled-1?line=7'>8</a> df.filter(col('x') < 2).arrange(desc('z'), 'x')

AttributeError: 'DataFrame' object has no attribute 'arrange'

What's genuinely odd about the above is that arrange works on its own and when it comes before filter.

# All of these work as expected
df.filter(col('x') < 2)
df.arrange(desc('z'), 'x')
df.arrange(desc('z'), 'x').filter(col('x') < 2)

A seemingly related issue is that I can't pass two arguments to filter when it follows arrange (or other verbs likeselect for that matter).

df.filter(col('x') < 2, col('y')>3) ## works
df.arrange(desc('z'), 'x').filter(col('x') < 2, col('y')>3) ## errors with "filter() takes 2 positional arguments but 3 were given"

Any ideas?

I'm on Python 3.9.2 installed via Homebrew on a 2019 Macbook (so regular Intel chip) and running the latest version of tidypolars (0.2.15).

First of all, I really like this package and I've started to use it a lot in my work. As a Pythonista whose first language is R, I really enjoy tidypolars.

In R, we can do something like the following

library(dplyr)
data(iris)

iris %>%
  group_by(Species) %>%
  mutate(
    result = Petal.Width - mean(Petal.Width)
  )

Since we have a group_by(Species) call, dplyr will subtract the mean that corresponds to each group in the mutate() operation (not the mean across all observations from all species).

As far as I understand, this is still not possible with tidypolars since we don't have a group_by function that behaves in a similar way to the one in dplyr. So my questions are

• Is it possible to have this behavior in tidypolars now?
  • If yes, how?
  • If not, is it going to be possible? I could volunteer to try to implement it. I'm not familiar with the existing codebase, but I suspect that Python eager evaluation of function arguments is what makes it harder to have such a feature?

Again, thanks for the fantastic library!

Forgive what's probably a dumb question, but is there a way to get .mutate to return the same object as the .bind_cols line?

import tidypolars as tp

tb = tp.Tibble({'a': [1, 2, 3]})
x = [4, 5, 6]
# gives desired output 
tb.bind_cols(tp.Tibble({'b': x}))
# gives error: ValueError: could not convert value '[4, 5, 6]' as a Literal
tb.mutate(b = x)

I noticed that in tidytable, you have purrr functions like map.(), but not in tidypolars.

Using for loops + lambda functions are just not desirable for collaborative coding / code readability/comprehension. In Python, even if there is a bit of sacrifice in performance, if it allows better code readability, it would be really nice to have.

Would something like map.() be in the scope of this repo?

When I chain filter expressions with | (error message said to use | and not or), I receive a ValueError message:

tp.Tibble(chr_col = tp.Series(['this is a test 1', 'this is a test 2', 'this is a test 3']))\
    .filter(col('chr_col') == 'this is a test 1' |
            col('chr_col') == 'this is a test 2')

ValueError: Since Expr are lazy, the truthiness of an Expr is ambiguous. 
Hint: use '&' or '|' to chain Expr together, not and/or.

It works fine if I do one or the other:

tp.Tibble(chr_col = tp.Series(['this is a test 1', 'this is a test 2', 'this is a test 3']))\
    .filter(# col('chr_col') == 'this is a test 1' |
            col('chr_col') == 'this is a test 2')

# chr_col
#   --
#   str
# "this is a test 2"

tp.Tibble(chr_col = tp.Series(['this is a test 1', 'this is a test 2', 'this is a test 3']))\
    .filter(col('chr_col') == 'this is a test 1' # |
            # col('chr_col') == 'this is a test 2'
            )

# chr_col
#   --
#   str
# "this is a test 1"

Good afternoon,

I think I found an issue with the as_date method. In the example per the documentation, the following succeeds:

import tidypolars as tp
from tidypolars import col

date_df = tp.Tibble(date = ['2021-12-31']) # Year-Month-Day (%Y-%m-%d)
date_df.mutate(date_parsed = tp.as_date(col('date'))) # Success

However when parsing different formats (using the fmt argument), the date fails to parse:

import tidypolars as tp
from tidypolars import col

date_df = tp.Tibble(date = ['12/31/2021']) # Month/Day/Year (%m/%d/%Y)
date_df.mutate(date_parsed = tp.as_date(col('date'), fmt='%m/%d/%Y')) # RuntimeError

I also extend my appreciation for all the work on this package. I've been searching for a tidyverse implementation in python and this one knocks my expectations out of the park. Thank you.

Should the syntax be the same as pl.DataFrame.rename? Currently polars mimics pandas syntax. Or should it be something that attempts to mimic tidyverse syntax?

Note: polars also has a .rename_col() with syntax df.rename_col('old', 'new').

PR that caused the break: https://github.com/pola-rs/polars/pull/4309

Old behavior that tidypolars relied on: https://github.com/pola-rs/polars/pull/2862

Really new to the library, but looking at the documentation did not really help with understanding.

Problem 1

import polars as pl
import tidypolars as tp
import csv
import requests

url = f'https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2022/2022-05-24/Scrumqueens-data-2022-05-23.csv'

df = tp.read_csv(file = url) # does not work
df = pl.read_csv(file = url) # works??

Problem 2

df = df.drop('...1', 'Notes') # does not work
df = df.drop('...1') # works separately
df = df.drop('Notes') # works separately

Problem 3

df.colnames
df.names
df.colnames()
df.names()
# None of these work

What am I missing, exactly?

Hi, it seems that the codebase is not annotated making the discoverability of methods difficult and static code analysis not working. Any plans on adding type hints?

Hi, There seems to be a problem with write_csv(). I can import tidypolars and the data just fine:

import tidypolars as tp

rents = tp.read_csv("https://raw.githubusercontent.com/rfordatascience/tidytuesday/master/data/2022/2022-07-05/rent.csv")

But when I try to export the data frame as a csv file:

rents.write_csv("rents.csv")

I get an error stating 'super' object has no attribute 'to_csv'.

The data come from the Tidytuesday repo. Python version is 3.10.8 and tidypolars is 0.2.19. I'm on macOS 13.

In R with lubridate, it would look like this:

one_year_before = some_date - years(1)
one_year_before = some_date - months(12)

But in tidypolars functions list, there doesn't seem to be a years or months function: https://tidypolars.readthedocs.io/en/latest/reference.html