The difference is that a is an empty nested array and that b is an empty simple array. The depths would be different. I tried this example on Dyalog and ≡a is 2, one level of nesting, while ≡b is 1, a simple vector.
Also see http://www.sudleyplace.com/APL/Prototype%20Functions.pdf On 1/29/14, Elias Mårtenson <loke...@gmail.com> wrote: > If I create an empty character array by selecting ⍬ from an array that > contains a string and a number, the result becomes what seems to be an > empty array with non-zero shape. > > The issue can best be explain by the following interaction. Note the > strange output from 8⎕CR: > > a←('foo' 9)[⍬] > b←'' > a≡b > 0 > a > b > 8⎕CR a > ┌⊖──┐ > │ │ > └───┘ > 8⎕CR b > ┌⊖┐ > │ │ > └─┘ > ⍴a > 0 > ⍴b > 0 > > > Regards, > Elias >
