array manipulation question 2

[ailse]

Hi,

I am trying to print an array such that each element is followed by the next one, with a tab character in between, and then a new line, so that:

@array = ("a", "b", "c", "d");

will be displayed as:

a   b
b   c
c   d

so far my code is:

my $i;

my @array = ("a", "b", "c", "d");

my $size = @array;

for ($i = 0; $i < $size; $i++) {
	print $array[$i] . "\t" . $array[$i+1] . "\n";
}

which is *sort of* working alright, except the result i'm getting with it is

a       b
b       c
c       d
Use of uninitialized value in concatenation (.) or string at next_array.pl line 13.
d

the first three lines are fine, but i don't want it to be "circular" i.e i need to stop it after the last item in the array, hope that makes sense. any tips on how to fix this would be great

 

[ishnid]

Just stop the loop one element earler:

for ($i = 0; $i < $size - 1; $i++) {

Or more perlishly:

for my $i ( 0 .. $size - 2 ) {

 

[ailse]

awesome, thanks

 

[stevexff]

for ($i = 0; $i < @array; $i++) {
    print $array[$i];
    print $i % 2 ? "\t" : "\n";
}

Note: not tested, but should produce

a     b
c     d
e

Is that what you want?


Steve

[small]"Every program can be reduced by one instruction, and every program has at least one bug. Therefore, any program can be reduced to one instruction which doesn't work." (Object:erlDesignPatterns)[/small]

 

[ailse]

thanks steve - but no, that's not quite what i was after, i didn't want the array to "loop round" as it were, so once the final value in the array is reached, the loop should stop. ishnid's suggestion has produced the output i wanted

 

[rharsh]

Just trying to kill time...

for (my $i = 0; $i <= $#array; $i+=2) {
    print $array[$i], $array[$i+1] ? "\t$array[$i+1]\n" : "\n";
}