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The following commit(s) were added to refs/heads/main by this push:
new 0bc2f31 Add array_empty (#931)
0bc2f31 is described below
commit 0bc2f31d8d9ac46e1732d1267cb8d83c38452f45
Author: kosiew <[email protected]>
AuthorDate: Tue Oct 29 00:03:00 2024 +0800
Add array_empty (#931)
---
docs/source/user-guide/common-operations/expressions.rst | 15 ++++++++++++++-
python/datafusion/functions.py | 6 ++++++
python/tests/test_functions.py | 4 ++++
src/functions.rs | 2 ++
4 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/docs/source/user-guide/common-operations/expressions.rst
b/docs/source/user-guide/common-operations/expressions.rst
index 6014c9d..77f3359 100644
--- a/docs/source/user-guide/common-operations/expressions.rst
+++ b/docs/source/user-guide/common-operations/expressions.rst
@@ -77,12 +77,25 @@ approaches.
df = ctx.from_pydict({"a": [[1, 2, 3], [4, 5, 6]]})
df.select(col("a")[0].alias("a0"))
-
.. warning::
Indexing an element of an array via ``[]`` starts at index 0 whereas
:py:func:`~datafusion.functions.array_element` starts at index 1.
+To check if an array is empty, you can use the function
:py:func:`datafusion.functions.array_empty`.
+This function returns a boolean indicating whether the array is empty.
+
+.. ipython:: python
+
+ from datafusion import SessionContext, col
+ from datafusion.functions import array_empty
+
+ ctx = SessionContext()
+ df = ctx.from_pydict({"a": [[], [1, 2, 3]]})
+ df.select(array_empty(col("a")).alias("is_empty"))
+
+In this example, the `is_empty` column will contain `True` for the first row
and `False` for the second row.
+
Structs
-------
diff --git a/python/datafusion/functions.py b/python/datafusion/functions.py
index 7273219..570a6ce 100644
--- a/python/datafusion/functions.py
+++ b/python/datafusion/functions.py
@@ -51,6 +51,7 @@ __all__ = [
"array_dims",
"array_distinct",
"array_element",
+ "array_empty",
"array_except",
"array_extract",
"array_has",
@@ -1160,6 +1161,11 @@ def array_element(array: Expr, n: Expr) -> Expr:
return Expr(f.array_element(array.expr, n.expr))
+def array_empty(array: Expr) -> Expr:
+ """Returns a boolean indicating whether the array is empty."""
+ return Expr(f.array_empty(array.expr))
+
+
def array_extract(array: Expr, n: Expr) -> Expr:
"""Extracts the element with the index n from the array.
diff --git a/python/tests/test_functions.py b/python/tests/test_functions.py
index 9353f87..e6fd41d 100644
--- a/python/tests/test_functions.py
+++ b/python/tests/test_functions.py
@@ -309,6 +309,10 @@ def py_flatten(arr):
lambda col: f.array_element(col, literal(1)),
lambda data: [r[0] for r in data],
],
+ [
+ lambda col: f.array_empty(col),
+ lambda data: [len(r) == 0 for r in data],
+ ],
[
lambda col: f.array_extract(col, literal(1)),
lambda data: [r[0] for r in data],
diff --git a/src/functions.rs b/src/functions.rs
index 24d33af..4facb6c 100644
--- a/src/functions.rs
+++ b/src/functions.rs
@@ -572,6 +572,7 @@ array_fn!(array_to_string, array delimiter);
array_fn!(array_dims, array);
array_fn!(array_distinct, array);
array_fn!(array_element, array element);
+array_fn!(array_empty, array);
array_fn!(array_length, array);
array_fn!(array_has, first_array second_array);
array_fn!(array_has_all, first_array second_array);
@@ -1003,6 +1004,7 @@ pub(crate) fn init_module(m: &Bound<'_, PyModule>) ->
PyResult<()> {
m.add_wrapped(wrap_pyfunction!(array_dims))?;
m.add_wrapped(wrap_pyfunction!(array_distinct))?;
m.add_wrapped(wrap_pyfunction!(array_element))?;
+ m.add_wrapped(wrap_pyfunction!(array_empty))?;
m.add_wrapped(wrap_pyfunction!(array_length))?;
m.add_wrapped(wrap_pyfunction!(array_has))?;
m.add_wrapped(wrap_pyfunction!(array_has_all))?;
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