| Author |
printing array problem
|
|
| Mark Day 2004-09-28, 9:03 am |
| Any tips on what I'm doing wrong here appreciated.
I'm using perl version 5.6.1 on Win98,
and this test script i've written, I was hoping would print each element
of this array, on a new line, then print the array again in reverse order.
What actually output's is the same array twice with all elements printed
on the same line.
What is wrong with my attempt to reverse the array, adn why does each
scalar not print on a new line?
thanks.
--code snippet---
#!C:\perl\bin\perl
@array = qq(1 2 3 4 5 6 7 8 9 10 11 12 baker's dozen);
foreach (@array)
{
print $_;
print "\n";
}
@array = reverse @array;
foreach (@array) {
print $_;
print "\n";
}
| |
| Mark Clements 2004-09-28, 9:03 am |
| Mark Day wrote:
> Any tips on what I'm doing wrong here appreciated.
>
> I'm using perl version 5.6.1 on Win98,
>
> and this test script i've written, I was hoping would print each element
> of this array, on a new line, then print the array again in reverse order.
>
> What actually output's is the same array twice with all elements printed
> on the same line.
>
> What is wrong with my attempt to reverse the array, adn why does each
> scalar not print on a new line?
>
> thanks.
>
> --code snippet---
>
> #!C:\perl\bin\perl
>
> @array = qq(1 2 3 4 5 6 7 8 9 10 11 12 baker's dozen);
qq() gives you an interpolated string - man perlop. what you are
effectively doing here is
@array = "1 2 3 4 5 6 7 8 9 10 11 12 baker's dozen";
which will set $array[0] to "1 2 3 4 5 6 7 8 9 10 11 12 baker's dozen"
and leave the rest of the array empty.
you probably mean
my @array = qw(1 2 3 4 5 6 7 8 9 10 11 12 baker's dozen);
though that will give you "baker's" and "dozen" as separate array elements.
You can also skip the
@array = reverse @array
step
ie
foreach( reverse @array){
....
Mark
| |
| Anno Siegel 2004-09-28, 9:03 am |
| Mark Day <soundz@techie.com> wrote in comp.lang.perl.misc:
> Any tips on what I'm doing wrong here appreciated.
>
> I'm using perl version 5.6.1 on Win98,
>
> and this test script i've written, I was hoping would print each element
> of this array, on a new line, then print the array again in reverse order.
>
> What actually output's is the same array twice with all elements printed
> on the same line.
>
> What is wrong with my attempt to reverse the array, adn why does each
> scalar not print on a new line?
>
> thanks.
>
> --code snippet---
>
> #!C:\perl\bin\perl
>
> @array = qq(1 2 3 4 5 6 7 8 9 10 11 12 baker's dozen);
[snip]
Look up what qq() does. I guess you meant to say qw() instead.
Anno
| |
| Graham Wood 2004-09-28, 9:03 am |
| Mark Day wrote:
>
> hoping would print each element
> of this array, on a new line, then print the array again in reverse order.
>
> What is wrong with my attempt to reverse the array, adn why does each
> scalar not print on a new line?
>
>
> #!C:\perl\bin\perl
>
> @array = qq(1 2 3 4 5 6 7 8 9 10 11 12 baker's dozen);
Your problem is that you're using qq which will surround the contents of
the parenthesis with double quotes rather than qw which will surround
each word in the parenthesis with double quotes. You are basically
creating and array with one element in it: "1 2 3 4 5 6 7 8 9 10 11 12
baker's dozen" and reversing this then gives you the same single element
in reverse order.
Replace qq with qw and see what happens.
Graham
>
> foreach (@array)
>
> {
>
> print $_;
>
> print "\n";
>
> }
>
> @array = reverse @array;
>
> foreach (@array) {
>
> print $_;
>
> print "\n";
>
> }
| |
| Mark Day 2004-09-28, 9:03 am |
|
Mark Clements wrote:
> qq() gives you an interpolated string - man perlop. what you are
> effectively doing here is
>
> @array = "1 2 3 4 5 6 7 8 9 10 11 12 baker's dozen";
>
> which will set $array[0] to "1 2 3 4 5 6 7 8 9 10 11 12 baker's dozen"
> and leave the rest of the array empty.
>
> you probably mean
>
> my @array = qw(1 2 3 4 5 6 7 8 9 10 11 12 baker's dozen);
> though that will give you "baker's" and "dozen" as separate array elements.
>
> You can also skip the
>
> @array = reverse @array
>
> step
>
> ie
>
> foreach( reverse @array){
>
> ...
>
> Mark
Great! thanks.
| |
| Anno Siegel 2004-09-28, 9:03 am |
| Graham Wood <Graham.T.Wood@oracle.com> wrote in comp.lang.perl.misc:
> Mark Day wrote:
[...]
>
> Your problem is that you're using qq which will surround the contents of
> the parenthesis with double quotes rather than qw which will surround
> each word in the parenthesis with double quotes.
That is wrong. "qw()" surrounds the whole string with single quotes,
then splits the result on whitespace.
Anno
| |
| Anno Siegel 2004-09-28, 9:03 am |
| Anno Siegel <anno4000@lublin.zrz.tu-berlin.de> wrote in comp.lang.perl.misc:
> Graham Wood <Graham.T.Wood@oracle.com> wrote in comp.lang.perl.misc:
>
> [...]
>
>
> That is wrong. "qw()" interprets the whole string in single-quote
> style, then splits the result on whitespace.
>
> Anno
| |
| Anno Siegel 2004-09-28, 9:03 am |
| Graham Wood <Graham.T.Wood@oracle.com> wrote in comp.lang.perl.misc:
> Mark Day wrote:
[...]
>
> Your problem is that you're using qq which will surround the contents of
> the parenthesis with double quotes rather than qw which will surround
> each word in the parenthesis with double quotes.
That is wrong. "qw()" treats the whole string as single quoted,
then splits the result on whitespace.
Anno
| |
| Graham Wood 2004-09-28, 9:03 am |
| Anno Siegel wrote:
>
> Graham Wood <Graham.T.Wood@oracle.com> wrote in comp.lang.perl.misc:
>
> [...]
>
>
> That is wrong. "qw()" treats the whole string as single quoted,
> then splits the result on whitespace.
Oh. Thanks
Graham
>
> Anno
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