ak.firsts

Defined in awkward.operations.ak_firsts on line 18.

ak.firsts(array, axis=1, *, highlevel=True, behavior=None, attrs=None)

Parameters:

• array – Array-like data (anything ak.to_layout recognizes).

• axis (int) – The dimension at which this operation is applied. The outermost dimension is 0, followed by 1, etc., and negative values count backward from the innermost: -1 is the innermost dimension, -2 is the next level up, etc.

• highlevel (bool) – If True, return an ak.Array; otherwise, return a low-level ak.contents.Content subclass.

• behavior (None or dict) – Custom ak.behavior for the output array, if high-level.

• attrs (None or dict) – Custom attributes for the output array, if high-level.

Selects the first element of each non-empty list and inserts None for each empty list.

For example,

>>> array = ak.Array([[1.1], [2.2], [], [3.3], [], [], [4.4], [5.5]])
>>> ak.firsts(array).show()
[1.1,
 2.2,
 None,
 3.3,
 None,
 None,
 4.4,
 5.5]

See ak.singletons to invert this function.