Re: hash values are printed in reverse order
[email protected] (Riehm Stephen) Fri, 23 Sep 2005 12:57:53 +0200
| Newsgroups | perl.scripts |
|---|---|
| Message-ID | <BF59AC51.1115F%[email protected]> |
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That's pretty easy to answer: hashes aren't sorted!
If you want them sorted, you either have to use
foreach $key ( sort keys %hash )
Or if they are to be kept in the order in which they were defined (ie:
chronological), you need to keep the keys in a separate array for =
sorting
purposes:
foreach $key ( @key_list )
{
print "$key: $hash{$key}\n" if exists $hash{$key};
}
See man perldata or perldsc for more information than you ever wanted to
know.
Steve
On 22.09.2005 19:59 Uhr, "neelay thaker" wrote:
> Hi,
> when I parse a list of comma separated IP addresses, put them into an =
array
> and then transfer the elements of the array into a hash, the hash =
elements get
> printed in reverse order as compared to the array and the input. The =
following
> code and output will make this problem clear.
> The code snipet is this-
> $arrsize =3D @ipaddr;
> for( $ctr =3D 0 ; $ctr < $arrsize ; $ctr++ )
> {
> $ip_intf_hash{ $ipaddr[$ctr] } =3D "";
> print $ipaddr[$ctr];
> print " : ";
> }
> print "\n";
> print "You entered the IPaddresses:\n";
> foreach $nfr ( keys %ip_intf_hash )
> {
> print "$nfr : ";
> }
> print "\n";
>=20
> The output looks like this-
> Enter the IP addresses: 2.2.2.2 <http://2.2.2.2> =
,3.3.3.3
> <http://3.3.3.3> ,1.1.1.1 <http://1.1.1.1>
> 2.2.2.2 <http://2.2.2.2> : 3.3.3.3 <http://3.3.3.3> : =
1.1.1.1
> <http://1.1.1.1> :
> You entered the IP addresses:
> 1.1.1.1 <http://1.1.1.1> : 3.3.3.3 <http://3.3.3.3> : =
2.2.2.2
> <http://2.2.2.2> :
> Any ideas on why the hash elements get reversed?
> Thanks.
>=20
> Neelay.
>=20
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<HTML>
<HEAD>
<TITLE>Re: hash values are printed in reverse order</TITLE>
</HEAD>
<BODY>
<FONT FACE=3D"Times New Roman"><SPAN STYLE=3D'font-size:14.0px'>That's =
pretty easy to answer: hashes aren't sorted!<BR>
If you want them sorted, you either have to use<BR>
<BR>
foreach $key ( sort keys %hash )<BR>
<BR>
Or if they are to be kept in the order in which they were defined (ie: =
chronological), you need to keep the keys in a separate array for =
sorting purposes:<BR>
<BR>
foreach $key ( @key_list )<BR>
{<BR>
print "$key: =
$hash{$key}\n" if exists $hash{$key};<BR>
}<BR>
<BR>
See man perldata or perldsc for more information than you ever wanted to =
know.<BR>
<BR>
<BR>
Steve<BR>
<BR>
<BR>
On 22.09.2005 19:59 Uhr, "neelay thaker" wrote:<BR>
<BR>
</SPAN></FONT><BLOCKQUOTE><FONT FACE=3D"Times New Roman"><SPAN =
STYLE=3D'font-size:14.0px'>Hi,<BR>
when I parse a list of comma separated IP addresses, put them into an =
array and then transfer the elements of the array into a hash, the hash =
elements get printed in reverse order as compared to the array and the =
input. The following code and output will make this problem clear.<BR>
The code snipet is this-<BR>
&=
nbsp; $arrsize =3D @ipaddr;<BR>
&=
nbsp; for( $ctr =3D 0 ; $ctr < $arrsize ; $ctr++ )<BR>
&=
nbsp; {<BR>
&=
nbsp; $ip_intf=
_hash{ $ipaddr[$ctr] } =3D "";<BR>
&=
nbsp; print =
$ipaddr[$ctr];<BR>
&=
nbsp; print =
" : ";<BR>
&=
nbsp; }<BR>
&=
nbsp; print "\n";<BR>
&=
nbsp; print "You entered the IPaddresses:\n";<BR>
&=
nbsp; foreach $nfr ( keys %ip_intf_hash )<BR>
&=
nbsp; {<BR>
&=
nbsp; print =
"$nfr : ";<BR>
&=
nbsp; }<BR>
&=
nbsp; print "\n";<BR>
<BR>
The output looks like this-<BR>
&=
nbsp; Enter the IP addresses: 2.2.2.2 <a =
href=3D"http://2.2.2.2"><http://2.2.2.2></a> ,3.3.3.3 <a =
href=3D"http://3.3.3.3"><http://3.3.3.3></a> ,1.1.1.1 <a =
href=3D"http://1.1.1.1"><http://1.1.1.1></a> <BR>
&=
nbsp; 2.2.2.2 <a =
href=3D"http://2.2.2.2"><http://2.2.2.2></a> : 3.3.3.3 <a =
href=3D"http://3.3.3.3"><http://3.3.3.3></a> : 1.1.1.1 <a =
href=3D"http://1.1.1.1"><http://1.1.1.1></a> :<BR>
&=
nbsp; You entered the IP addresses:<BR>
&=
nbsp; 1.1.1.1 <a href=3D"http://1.1.1.1"><http://1.1.1.1></a> =
: 3.3.3.3 <a href=3D"http://3.3.3.3"><http://3.3.3.3></a> =
: 2.2.2.2 <a href=3D"http://2.2.2.2"><http://2.2.2.2></a> =
:<BR>
Any ideas on why the hash elements get reversed?<BR>
Thanks.<BR>
<BR>
Neelay.<BR>
<BR>
</SPAN></FONT></BLOCKQUOTE><FONT FACE=3D"Times New Roman"><SPAN =
STYLE=3D'font-size:14.0px'><BR>
</SPAN></FONT>
</BODY>
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