From: Ralf Mueller <ralf.mueller@...>
Date: 2009-09-04T18:25:04+09:00
Subject: Re: Array.transpose on [[]] or [[],[]]

Sebastian Hungerecker wrote:
> Ralf Mueller wrote:
>   
>> I wondered why [[]].transpose = [] and [[],[]].transpose = []
>> I expected them to be [[]], because the result would still be an array
>> of arrays.
>>     
>
> You can think of [] as an array of 0 arrays in this case.
> The number of arrays in the array returned by transpose equals the number
> of items in each subarray of the original array. So if that number is 0, it
> makes sense that the returned array would also have 0 subarrays.
>
> HTH,
> Sebastian
Hi Sebastian,
sure, but [[]] has a subarray. so, shouldn't [[]].transpose have one too? 
To point it out in a more general way: I thought, if 'transpose' can be 
applied to an array, it should behave like an involution: 
a.transpose.transpose = a.

anyway, one more thing to remember...


Thanks and best regards
Ralf