code: def hstack(tup):
      """
      Stack arrays in sequence horizontally (column wise).
  
      This is equivalent to concatenation along the second axis, except for 1-D
      arrays where it concatenates along the first axis. Rebuilds arrays divided
      by `hsplit`.
  
      This function makes most sense for arrays with up to 3 dimensions. For
      instance, for pixel-data with a height (first axis), width (second axis),
      and r/g/b channels (third axis). The functions `concatenate`, `stack` and
      `block` provide more general stacking and concatenation operations.
  
      Parameters
      ----------
      tup : sequence of ndarrays
          The arrays must have the same shape along all but the second axis,
          except 1-D arrays which can be any length.
  
      Returns
      -------
      stacked : ndarray
          The array formed by stacking the given arrays.
  
      See Also
      --------
      stack : Join a sequence of arrays along a new axis.
      vstack : Stack arrays in sequence vertically (row wise).
      dstack : Stack arrays in sequence depth wise (along third axis).
      concatenate : Join a sequence of arrays along an existing axis.
      hsplit : Split array along second axis.
      block : Assemble arrays from blocks.
  
      Examples
      --------
      >>> a = np.array((1,2,3))
      >>> b = np.array((2,3,4))
      >>> np.hstack((a,b))
      array([1, 2, 3, 2, 3, 4])
      >>> a = np.array([[1],[2],[3]])
      >>> b = np.array([[2],[3],[4]])
      >>> np.hstack((a,b))
      array([[1, 2],
             [2, 3],
             [3, 4]])
  
      """
      _warn_for_nonsequence(tup)
      arrs = [atleast_1d(_m) for _m in tup]
      # As a special case, dimension 0 of 1-dimensional arrays is "horizontal"
      if arrs and arrs[0].ndim == 1:
          return _nx.concatenate(arrs, 0)
      else:
          return _nx.concatenate(arrs, 1)
  
imports: from __future__ import division, absolute_import, print_function
  import functools
  import operator
  import types
  import warnings
  from .None import numeric
  from .None import overrides
  from .numeric import array, asanyarray, newaxis
  from .multiarray import normalize_axis_index
label_desc: Use image node_id 11 for calling a global function with example usage: hstack(tup) and returns: _nx, _nx