arkouda.join
============

.. py:module:: arkouda.join


Functions
---------

.. autoapisummary::

   arkouda.join.compute_join_size
   arkouda.join.gen_ranges
   arkouda.join.join_on_eq_with_dt


Module Contents
---------------

.. py:function:: compute_join_size(a: arkouda.pdarrayclass.pdarray, b: arkouda.pdarrayclass.pdarray) -> Tuple[int, int]

   Compute the internal size of a hypothetical join between a and b. Returns
   both the number of elements and number of bytes required for the join.


.. py:function:: gen_ranges(starts, ends, stride=1, return_lengths=False)

   Generate a segmented array of variable-length, contiguous ranges between pairs of
   start- and end-points.

   :param starts: The start value of each range
   :type starts: pdarray, int64
   :param ends: The end value (exclusive) of each range
   :type ends: pdarray, int64
   :param stride: Difference between successive elements of each range
   :type stride: int
   :param return_lengths: Whether or not to return the lengths of each segment. Default False.
   :type return_lengths: bool, optional

   :returns: * **segments** (*pdarray, int64*) -- The starting index of each range in the resulting array
             * **ranges** (*pdarray, int64*) -- The actual ranges, flattened into a single array
             * **lengths** (*pdarray, int64*) -- The lengths of each segment. Only returned if return_lengths=True.


.. py:function:: join_on_eq_with_dt(a1: arkouda.pdarrayclass.pdarray, a2: arkouda.pdarrayclass.pdarray, t1: arkouda.pdarrayclass.pdarray, t2: arkouda.pdarrayclass.pdarray, dt: Union[int, numpy.int64], pred: str, result_limit: Union[int, numpy.int64] = 1000) -> Tuple[arkouda.pdarrayclass.pdarray, arkouda.pdarrayclass.pdarray]

   Performs an inner-join on equality between two integer arrays where
   the time-window predicate is also true

   :param a1: pdarray to be joined
   :type a1: pdarray, int64
   :param a2: pdarray to be joined
   :type a2: pdarray, int64
   :param t1: timestamps in millis corresponding to the a1 pdarray
   :type t1: pdarray
   :param t2: timestamps in millis corresponding to the a2 pdarray
   :type t2: pdarray
   :param dt: time delta
   :type dt: Union[int,np.int64]
   :param pred: time window predicate
   :type pred: str
   :param result_limit: size limit for returned result
   :type result_limit: Union[int,np.int64]

   :returns: * **result_array_one** (*pdarray, int64*) -- a1 indices where a1 == a2
             * **result_array_one** (*pdarray, int64*) -- a2 indices where a2 == a1

   :raises TypeError: Raised if a1, a2, t1, or t2 is not a pdarray, or if dt or
       result_limit is not an int
   :raises ValueError: if a1, a2, t1, or t2 dtype is not int64, pred is not
       'true_dt', 'abs_dt', or 'pos_dt', or result_limit is < 0