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new 37cd34dfb1 Improve documentation for `nullif` kernel (#6658)
37cd34dfb1 is described below
commit 37cd34dfb199474053c2ca578c6c2d79296e1540
Author: Andrew Lamb <[email protected]>
AuthorDate: Thu Oct 31 14:38:14 2024 -0400
Improve documentation for `nullif` kernel (#6658)
* Improve `nullif` docs
* Improve documentation for `nullif` kernel
---
arrow-select/src/nullif.rs | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/arrow-select/src/nullif.rs b/arrow-select/src/nullif.rs
index d1e3c35bfb..4b90114a4b 100644
--- a/arrow-select/src/nullif.rs
+++ b/arrow-select/src/nullif.rs
@@ -22,10 +22,25 @@ use arrow_buffer::buffer::{bitwise_bin_op_helper,
bitwise_unary_op_helper};
use arrow_buffer::{BooleanBuffer, NullBuffer};
use arrow_schema::{ArrowError, DataType};
-/// Copies original array, setting validity bit to false if a secondary
comparison
-/// boolean array is set to true
+/// Returns a new array with the same values and the validity bit to false
where
+/// the corresponding element of`right` is true.
///
-/// Typically used to implement NULLIF.
+/// This can be used to implement SQL `NULLIF`
+///
+/// # Example
+/// ```
+/// # use arrow_array::{Int32Array, BooleanArray};
+/// # use arrow_array::cast::AsArray;
+/// # use arrow_array::types::Int32Type;
+/// # use arrow_select::nullif::nullif;
+/// // input is [null, 8, 1, 9]
+/// let a = Int32Array::from(vec![None, Some(8), Some(1), Some(9)]);
+/// // use nullif to set index 1 to null
+/// let bool_array = BooleanArray::from(vec![Some(false), Some(true),
Some(false), None]);
+/// let nulled = nullif(&a, &bool_array).unwrap();
+/// // The resulting array is [null, null, 1, 9]
+/// assert_eq!(nulled.as_primitive(), &Int32Array::from(vec![None, None,
Some(1), Some(9)]));
+/// ```
pub fn nullif(left: &dyn Array, right: &BooleanArray) -> Result<ArrayRef,
ArrowError> {
let left_data = left.to_data();
