long[][] (Groovy JDK enhancements)

Package:

## Class long[][]

- - ### Methods Summary

    Methods
    Return type | Name and parameters
    --- | ---
    `long[]` | `column(int col)` Select a column from a 2D array.
    `long[][]` | `eachColumn(Closure closure)` Process the columns of the array.
    `List` | `flatten()` Flattens a 2D array into a new collection.
    `long[][]` | `transpose()` A transpose method for 2D long arrays.
    `Iterator` | `transposing()` An iterator of the columns of the array.

- - ### Methods Detail

    - #### public long[] column(int col)

      Select a column from a 2D array.

          long[][] nums = [[1L, 2L], [10L, 20L]]
          assert nums.column(0) == [1L, 10L] as long[]
          assert nums.column(1) == [2L, 20L] as long[]

      Parameters:
      Returns:
        a long[]
      Since:
        5.0.0

    - #### public long[][] eachColumn(Closure closure)

      Process the columns of the array.

          double[][] nums = [[1L, 2L], [10L, 20L]]
          nums.eachColumn {
              assert it[0] * 10L == it[1]
          }

      Parameters:
        `closure` - the closure applied on each array column
      Returns:
        the self array
      Since:
        5.0.0

    - #### public List flatten()

      Flattens a 2D array into a new collection. The items are copied row by row.

      Example usage:

          long[][] array = [[0, 1], [2, 3]]
          assert array.flatten() == [0, 1, 2, 3]

      Returns:
        a Collection of the array elements
      Since:
        5.0.0

    - #### public long[][] transpose()

      A transpose method for 2D long arrays.

      Example usage:

          long[][] longs = [[1L, 3L, 5L], [2L, 4L, 6L]]
          long[][] expected = [[1L, 2L], [3L, 4L], [5L, 6L]]
          def result = longs.transpose()
          assert result == expected
          assert longs.class.componentType == result.class.componentType

      Returns:
        the transposed 2D long array
      Since:
        3.0.8

    - #### public Iterator transposing()

      An iterator of the columns of the array.

          long[][] nums = [[1L, 2L], [10L, 20L]]
          assert nums.transpose() == nums.transposing().toList()
          assert nums.transposing().collect{ long[] col -> col.sum() } == [11L, 22L]

      Returns:
        the iterator
      Since:
        5.0.0