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Re: "shift" not working as expected

by flexvault (Monsignor)
on Mar 20, 2016 at 16:40 UTC ( [id://1158361] : note . print w/replies, xml ) Need Help??

in reply to "shift" not working as expected


Forget about this answer, looked again, and I'm wrong! Not enough coffee yet!


for (1 .. $max) { sendX; }
should be:
for (0 .. $max) { sendX; }
whether or not your 'sub sendX' is correct!


"Well done is better than well said." - Benjamin Franklin

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Re^2: "shift" not working as expected
by Marshall (Canon) on Mar 20, 2016 at 18:46 UTC
    I think the key thing is the use of "if not defined" instead of a numeric/Boolean comparison. A 0 or 1 start for loop doesn't matter (0,1,2,3) or (1,2,3), and actually $count and $max in the sub() don't really either as far as the sub is concerned except that those factors limit the number of times the sub is called in the for() loop. In the OP's code using 1..$max calls the sub 3 times, using 0..$max calls it 4 times.

    #!/usr/bin/perl use 5.014; use strict; use warnings; use autodie; my @arrX = (0,4194304,8388608); my $count = 0; #makes no difference in sub my $max = 300; #makes no difference in sub sub sendX { my ($data) = shift @arrX; return if not defined $data; # use defined, not numeric/boolea +n say $data; } for (1 .. $max) { #could be 1 .. scalar(@arrX)??? sendX; } __END__ Prints: 0 4194304 8388608
    I am also a bit mystified as to how this relates to some purpose.