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Re: Possible PEP - two dimensional arrays?

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  Re: Possible PEP - two dimensional arrays? Terry Reedy <tjreedy@udel.edu> - 2016-06-08 03:07 -0400
    Re: Possible PEP - two dimensional arrays? wxjmfauth@gmail.com - 2016-06-08 01:13 -0700

#109658 — Re: Possible PEP - two dimensional arrays?

On 6/7/2016 8:17 PM, Harrison Chudleigh wrote:
> I was programming a computer game and found that while 1D arrays can be
> created using the module array, there is no module for two-dimensional
> arrays, unlike languages like C. Currently, the closest thing Python has to
> a 2D array is a dictionary containing lists.

A list of lists is standard if one is not using numpy, indexed as, for 
instance 'board[i][j]' A tuple of tuples can be used for static 2d 
array.  I expect people have also used a list of arrays, though for most 
games, the space saving is not enough, plus a list of list is more 
flexible, in that one can put a 'piece' on and 'square'.

> I propose that a module , 2DArray, be added to the standard library. This
> module will include:
> Assignment and retrieval on items on a two-dimensional, finite rectangular
> grid. Types are integer, float, character and string.
> Resizing the grid - parameters are old size and new size. Any new elements
> are initialized with a value of 0 for int, 0.0 for float and ' ' for string
> and character arrays.
> Removing elements. The parameter is the location. After removal, the value
> returned is 0 for int, 0.0 for float and ' ' for string and character
> arrays.
> A function, pop(), which removes elements from the grid and then returns
> them.

You could create your own class based on a list of arrays, and even 
publish it.

-- 
Terry Jan Reedy

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#109662

Lists (list of lists) in action.

>>> sys.version
'3.2.5 (default, May 15 2013, 23:06:03) [MSC v.1500 32 bit (Intel)]'
>>>
>>> zz = vecmat.NewMat(3, 2)
>>> zz[0][0] = 1.0; zz[0][1] = 2.0
>>> zz[1][0] = 3.0; zz[1][1] = 4.0
>>> zz[2][0] = 5.0; zz[2][1] = 5.0
>>> zz
[[1.0, 2.0], [3.0, 4.0], [5.0, 5.0]]
>>> vmio.pr(zz, 'zz=')
zz=
(   1.00000e+000  2.00000e+000 )
(   3.00000e+000  4.00000e+000 )
(   5.00000e+000  5.00000e+000 )
>>> aa, b, cc = svdecomp.SVDecomp(zz)
>>> bb = vecmat.VecToDiagMat(b)
>>> cct = vecmat.TransposeMat(cc)
>>> vmio.pr(aa, 'aa=')
aa=
(   6.91451e-001 -2.42761e-001 )
(   4.73049e-001 -5.59698e-001 )
(  -5.46004e-001 -7.92342e-001 )
>>> vmio.pr(bb, 'bb=')
bb=
(   8.25102e-001  0.00000e+000 )
(   0.00000e+000  8.90613e+000 )
>>> vmio.pr(cct, 'cct=')
cct=
(  -7.50721e-001  6.60619e-001 )
(  -6.60619e-001 -7.50721e-001 )
>>> rr = vecmat.MatMulMatMulMat(aa, bb, cct)
>>> vmio.pr(rr, 'rr=')
rr=
(   1.00000e+000  2.00000e+000 )
(   3.00000e+000  4.00000e+000 )
(   5.00000e+000  5.00000e+000 )
>>>

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