[Numpy-discussion] numarray: "concatenate along new axis" returns 'unexpected' type

Sebastian Haase haase at msg.ucsf.edu
Tue Feb 8 10:53:38 CST 2005


Hi,
from the numarray documentation:
<doc>
concatenate(arrs, axis=0)
Returns a new array containing copies of the data contained in all arrays # of 
arrs= (a0, a1, ... an). The arrays ai will be concatenated along the 
specified axis (default=0). All arrays ai must have the same shape along 
every axis except for the one specified in axis. To concatenate arrays along 
a newly created axis, you can use array((a0, ..., an)), as long as all arrays 
have the same shape. 
</doc>

Is it a bug that array((a0,a1)) returns different type that a0 ? 
(type(a0)==type(a1))

>>> a = na.zeros((3,3),na.UInt16)
>>> b = na.zeros((3,3),na.UInt16)
>>> na.concatenate((a,b))
[[0 0 0]
 [0 0 0]
 [0 0 0]
 [0 0 0]
 [0 0 0]
 [0 0 0]]
>>> _.type()
UInt16
>>> na.array((a,b))
[[[0 0 0]
  [0 0 0]
  [0 0 0]]

 [[0 0 0]
  [0 0 0]
  [0 0 0]]]
>>> _.type()
Int32



Thanks,
Sebastian Haase




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