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Column
Column is a lazy, whole-column expression you build with Python operators, then pass to Table.filter or Table.with_column. Reference with the operator table.
t["name"] returns a Column — a lazy expression over one pyarrow ChunkedArray. You build it
with ordinary Python operators, then hand it to filter or
with_column. Each operator compiles to a single
pyarrow.compute kernel and returns a new Column, so t["x"] * 2 and t["g"] > 0.5 stay
whole-column and C++-fast — no Python row loop ever runs.
| Category | Operators | Result |
|---|---|---|
| Arithmetic | + - * / |
a numeric Column |
| Comparison | > >= < <= == != |
a boolean Column (a mask) |
| Boolean | & (and) · | (or) · ~ (not) |
a boolean Column |
| Null checks | is_valid() · is_null() |
a boolean Column |
Usage#
Python
from lsdtools import Table
t = Table({"name": ["ann", None, "cy"], "score": [12, 30, 7]})
mask = (t["score"] > 10) & t["name"].is_valid()
t.filter(mask).print()
# → name:["ann"] score:[12]
Build a derived column the same way and store it with with_column:
Python
t.with_column("bonus", t["score"] * 2)
Where to start#
Learn — Tables & data flow · Shape steps
Examples — Clean a CSV
API — Table · filter · with_column
Properties
- arrow the underlying pyarrow ChunkedArray, zero-copy
Methods
- is_null a bool column, true where the value is null
- is_valid a bool column, true where the value is present (not null)
By LSD Team · Last updated Jul 17, 2026
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