take

datafusion_python::datafusion_common::arrow::compute

Function take 

Source 
pub fn take(
    values: &dyn Array,
    indices: &dyn Array,
    options: Option<TakeOptions>,
) -> Result<Arc<dyn Array>, ArrowError>
Expand description

Take elements by index from Array, creating a new Array from those indexes.

┌─────────────────┐      ┌─────────┐                              ┌─────────────────┐
│        A        │      │    0    │                              │        A        │
├─────────────────┤      ├─────────┤                              ├─────────────────┤
│        D        │      │    2    │                              │        B        │
├─────────────────┤      ├─────────┤   take(values, indices)      ├─────────────────┤
│        B        │      │    3    │ ─────────────────────────▶   │        C        │
├─────────────────┤      ├─────────┤                              ├─────────────────┤
│        C        │      │    1    │                              │        D        │
├─────────────────┤      └─────────┘                              └─────────────────┘
│        E        │
└─────────────────┘
   values array          indices array                              result

For selecting values by index from multiple arrays see crate::interleave

Note that this kernel, similar to other kernels in this crate, will avoid allocating where not necessary. Consequently the returned array may share buffers with the inputs

§Errors

This function errors whenever:

  • An index cannot be casted to usize (typically 32 bit architectures)
  • An index is out of bounds and options is set to check bounds.

§Safety

When options is not set to check bounds, taking indexes after len will panic.

§See also

§Examples

let values = StringArray::from(vec!["zero", "one", "two"]);

// Take items at index 2, and 1:
let indices = UInt32Array::from(vec![2, 1]);
let taken = take(&values, &indices, None).unwrap();
let taken = taken.as_string::<i32>();

assert_eq!(*taken, StringArray::from(vec!["two", "one"]));