Re^3: pruning of empty arrayrefs in nested array

I certainly do not want to be nitpicking with you, but it seems to me that deleting an array element does not exactly sets it to undef,

@a = 1..3;;
pp \@a;;
[1, 2, 3]

delete $a[1];;
pp \@a;;
[1, undef, 3]
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Close enough for me :)

but rather to "empty slot".... I have no idea of what the difference is.

A Perl array consists of a C array of pointers to scalars.

delete sets the value of the C pointer to 0; and the debugger reports that as "Empty slot"; but in all other circumstances is detected and reported as undef.

If you manually set the value of an array element to undef, then the C array pointer is set to point to the undef, which is a static pointer value that is defined to be undefined :)

It does not make a practical difference for the programmer

Agreed!

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

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