sorting array of hash in hash

[dillipkumar]

Hi,
I have a Hash:

%hash= 'student'  => [
                                    {
                                       'roll_no' => 10,
                                       'sub' => 'eng'
                                       marks => 32,
                                    },
                                    {
                                       'roll_no' => 11,
                                       'sub' => 'math'
                                       marks => 69,
                                    },
                                    {
                                       'roll_no' => 10
                                       'sub' => 'science'
                                       marks => 69,
                                    },

                                    {
                                       'roll_no' => 25
                                       'sub' => 'geo'
                                       marks => 59
                                    },

                                ],

I want to sort the hash according to sorting of 'roll_no' ..
After sorting It should be displayed

%hash= 'student'  => [
                                    {
                                       'roll_no' => 10,
                                       'sub' => 'eng'
                                       marks => 32,
                                    },
                                     {
                                       'roll_no' => 10
                                       'sub' => 'science'
                                       marks => 69,
                                    },

                                     {
                                       'roll_no' => 11,
                                       'sub' => 'math'
                                       marks => 69,
                                    },
                                   
                                    {
                                       'roll_no' => 25
                                       'sub' => 'geo'
                                       marks => 59
                                    },

                                ],

Can anybody help me...

[KevinADC]

Is this school/class/course work?

[Ganon11]

A hash has no order. If you want to have data sorted, use an array instead.

[KevinADC]

A hash has no order. If you want to have data sorted, use an array instead.

It is possible but I would also recommend using an array. See Tie::SortHash and Tie::IxHash.

[dillipkumar]

Hi,
Actually this is a task..
The Original Hash is like this:
[CODE=perl]%hash = ( 'difference' => [
{
'line_number' => '21',
'filename' => 'BRANCH27',
'source_line' => {},
'target_line' => '001S TR'
},
{
'line_number' => '1',
'filename' => 'BRANCH',
'source_line' => {},
'target_line' => '023X '
},
{
'line_number' => '140',
'filename' => 'BRANCH',
'source_line' => {},
'target_line' => '139FIFTH'
},
{
'line_number' => '1',
'filename' => 'ACCOUNT27',
'source_line' => {},
'target_line' => '0223X '
},
],

);[/CODE]
i want to sort this hash..

[dillipkumar]

A hash has no order. If you want to have data sorted, use an array instead.

Hi The Original hash is like this:

%hash = ( 'difference' => [
								{
								  'line_number' => '21',
								  'filename' => 'BRANCH27',
								  'source_line' => {},
								  'target_line' => '001S TR'
								},
								{
								  'line_number' => '1',
								  'filename' => 'BRANCH',
								  'source_line' => {},
								  'target_line' => '023X '
								},
								{
								  'line_number' => '140',
								  'filename' => 'BRANCH',
								  'source_line' => {},
								  'target_line' => '139FIFTH' 
								},
								{
								  'line_number' => '1',
								  'filename' => 'ACCOUNT27',
								  'source_line' => {},
								  'target_line' => '0223X '
								},
							 ], 
	
			 );

[nithinpes]

Hi The Original hash is like this:
%hash = ( 'difference' => [
{
'line_number' => '21',
'filename' => 'BRANCH27',
'source_line' => {},
'target_line' => '001S TR'
},
{
'line_number' => '1',
'filename' => 'BRANCH',
'source_line' => {},
'target_line' => '023X '
},
{
'line_number' => '140',
'filename' => 'BRANCH',
'source_line' => {},
'target_line' => '139FIFTH'
},
{
'line_number' => '1',
'filename' => 'ACCOUNT27',
'source_line' => {},
'target_line' => '0223X '
},
],

);

The structure is hash of array of hashes. To display it sorted according to 'line_number' foreach top-level key('difference '), you would be actually sorting the array and not the hash (according to the intended output you posted in your initial description).
You can use:

foreach $k (keys %hash) {
print "\n\n$k \n\n";
 foreach $a (sort {$a->{'line_number'} <=> $b->{'line_number'}} @{$hash{$k}}) {
  print "$_   : $a->{$_}\n" foreach(keys %{$a});
  print "\n";
   }
}

[dillipkumar]

The structure is hash of array of hashes. To display it sorted according to 'line_number' foreach top-level key('difference '), you would be actually sorting the array and not the hash (according to the intended output you posted in your initial description).
You can use:

foreach $k (keys %hash) {
print "\n\n$k \n\n";
 foreach $a (sort {$a->{'line_number'} <=> $b->{'line_number'}} @{$hash{$k}}) {
  print "$_   : $a->{$_}\n" foreach(keys %{$a});
  print "\n";
   }
}

Hi Nitin,

Now it is working but the 'source_line' returns the hash like:
source_line : HASH(0x81ffdac)

[nithinpes]

Hi Nitin,

Now it is working but the 'source_line' returns the hash like:
source_line : HASH(0x81ffdac)

That is because you have an empty hash as value for 'source_line' key.

[dillipkumar]

That is because you have an empty hash as value for 'source_line' key.

Actually after executing it is displaying this format -->

{
filename' => 'BRANCH27',
line_number' => '21',
'source_line' => {},
'target_line' => '001S TR'
}

But the Actually Hash is in this format:
{
'line_number' => '21',
'filename' => 'BRANCH27',
'source_line' => {},
'target_line' => '001S TR'
},

[nithinpes]

Actually after executing it is displaying this format -->

{
'line_number' => '21',
'filename' => 'BRANCH27',
'source_line' => {},
'target_line' => '001S TR'
},

But the Actually Hash is in this format:

{
filename' => 'BRANCH27',
line_number' => '21',
'source_line' => {},
'target_line' => '001S TR'
}

That's typically the behaviour of hash, the order won't be maintained. If you want to retain to retain the order, you can pass the order of keys into an array and use it while displaying.

@keys=('filename','line_number','source_line','target_line'); ## use the order of your choice
foreach $k (keys %hash) {
print "\n\n$k \n\n";
 foreach $a (sort {$a->{'line_number'} <=> $b->{'line_number'}} @{$hash{$k}}) {
  print "$_   : $a->{$_}\n" foreach(@keys); ## use @keys here
  print "\n";
   }
}

You would not have had this question if you had gone through Tie::SortHash that KevinADC mentioned in his reply.

[dillipkumar]

That's typically the behaviour of hash, the order won't be maintained. If you want to retain to retain the order, you can pass the order of keys into an array and use it while displaying.

@keys=('filename','line_number','source_line','target_line'); ## use the order of your choice
foreach $k (keys %hash) {
print "\n\n$k \n\n";
 foreach $a (sort {$a->{'line_number'} <=> $b->{'line_number'}} @{$hash{$k}}) {
  print "$_   : $a->{$_}\n" foreach(@keys); ## use @keys here
  print "\n";
   }
}

You would not have had this question if you had gone through Tie::SortHash that KevinADC mentioned in his reply.

Thank Nitin for ur help...

[eWish]

dillipkumar,

Four out of the the five posts that you have made in this tread you have neglected to use the code tags. Please use the code tags when posting code and data samples on this site.

[CODE]...your code goes here...[/CODE]

Thank You!

--Kevin