feat: use ibis.desc()/.desc() with selectors

[lostmygithubaccount]

Is your feature request related to a problem?

I want to be able to order by column name(s) that contain count after doing value_counts()

What is the motivation behind your request?

[ins] In [1]: import ibis

[ins] In [2]: import ibis.selectors as s

[ins] In [3]: ibis.options.interactive = True

[ins] In [4]: t = ibis.examples.penguins.fetch()

[ins] In [5]: t.select("species", "island").value_counts().order_by(s.contains("count"))
Out[5]:
┏━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━┓
┃ species   ┃ island    ┃ species_island_count ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━┩
│ string    │ string    │ int64                │
├───────────┼───────────┼──────────────────────┤
│ Adelie    │ Biscoe    │                   44 │
│ Adelie    │ Torgersen │                   52 │
│ Adelie    │ Dream     │                   56 │
│ Chinstrap │ Dream     │                   68 │
│ Gentoo    │ Biscoe    │                  124 │
└───────────┴───────────┴──────────────────────┘

[nav] In [6]: t.select("species", "island").value_counts().order_by(ibis.desc(s.contains("count")))
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In[6], line 1
----> 1 t.select("species", "island").value_counts().order_by(ibis.desc(s.contains("count")))

File ~/repos/ibis/ibis/expr/api.py:612, in desc(expr)
    576 def desc(expr: ir.Column | str) -> ir.Value:
    577     """Create a descending sort key from `expr` or column name.
    578
    579     Parameters
   (...)
    610
    611     """
--> 612     return _deferred_method_call(expr, "desc")

File ~/repos/ibis/ibis/expr/api.py:573, in _deferred_method_call(expr, method_name)
    571 else:
    572     value = expr
--> 573 return method(value)

AttributeError: 'Predicate' object has no attribute 'desc'

[nav] In [7]: t.select("species", "island").value_counts().order_by(s.contains("count").desc())
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
Cell In[7], line 1
----> 1 t.select("species", "island").value_counts().order_by(s.contains("count").desc())

AttributeError: 'Predicate' object has no attribute 'desc'

Describe the solution you'd like

the above works

What version of ibis are you running?

main

What backend(s) are you using, if any?

duckdb

Code of Conduct

• I agree to follow this project's Code of Conduct

[cpcloud]

@lostmygithubaccount Is there an equivalent dplyr syntax here? Would be good to mirror that as much as possible if it exists.

[cpcloud]

Looks like in dplyr you can use across:

And for desc as well:

If that doesn't work we should implement it that way.

Reference: https://dplyr.tidyverse.org/reference/arrange.html

[cpcloud]

Looks like that method already works, so let's document it and close this out!

In [8]: from ibis.interactive import *

In [9]: t = ex.penguins.fetch()

In [10]: expr = t.select("species", "island").value_counts().order_by(s.across(s.contains("count"), _.desc()))

In [11]: ibis.to_sql(expr)
Out[11]:
SELECT
  *
FROM (
  SELECT
    "t1"."species",
    "t1"."island",
    COUNT(*) AS "species_island_count"
  FROM (
    SELECT
      "t0"."species",
      "t0"."island"
    FROM "penguins" AS "t0"
  ) AS "t1"
  GROUP BY
    1,
    2
) AS "t2"
ORDER BY
  "t2"."species_island_count" DESC

In [12]: expr
Out[12]:
┏━━━━━━━━━━━┳━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━┓
┃ species   ┃ island    ┃ species_island_count ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━┩
│ string    │ string    │ int64                │
├───────────┼───────────┼──────────────────────┤
│ Gentoo    │ Biscoe    │                  124 │
│ Chinstrap │ Dream     │                   68 │
│ Adelie    │ Dream     │                   56 │
│ Adelie    │ Torgersen │                   52 │
│ Adelie    │ Biscoe    │                   44 │
└───────────┴───────────┴──────────────────────┘