in reply to appending and array into last element of an array?

You can't store an array in an array, but you can store a reference to one. 
# Saves a reference to the existing array.
push(@arrayA, \@arrayB);

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# Creates a new (anon) array and saves a reference to it.
push(@arrayA, [ @arrayB ]);

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Re^2: appending and array into last element of an array?
by mdunnbass (Monk) on Oct 11, 2006 at 16:30 UTC
    OK. that sounds good so far, but if I'm doing this in a looping context, and the next time around the loop, the values of @arrayB change, won't that change all of the references as well?

    Also, how could I save the anon array in your second example? setting something equal to the push gives the length of the new array, right? Could I just do 

    push(@arrayA, [ @arrayB ]);
@new_array = @_;

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    would that work?

    And thanks for the quick reply.
    Matt

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      OK. that sounds good so far, but if I'm doing this in a looping context, and the next time around the loop, the values of @arrayB change, won't that change all of the references as well?

      It depends on where @arrayB is declared. 

      my @arrayA;
my @arrayB;
while (...) {
   @arrayB = ...;
   push(@arrayA, \@arrayB);  # XXX
}

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      my @arrayA;
my @arrayB;
while (...) {
   @arrayB = ...;
   push(@arrayA, [ @arrayB ]);  # Ok
}

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      my @arrayA;
while (...) {
   my @arrayB = ...;
   push(@arrayA, \@arrayB);  # Ok
}

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      my @arrayA;
while (...) {
   my @arrayB = ...;
   push(@arrayA, [ @arrayB ]);  # Needlessly creating 3rd array.
}

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      Also, how could I save the anon array in your second example?

      What does "save" mean? Copy? You already have a copy of the array in @arrayB.

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