extract column from multidimentional array

Hi,

below you will find the code for a small script where i'm able to extract a row but not a column.

So the question is how can I do that.

Here is the code:

<?php

$arr = array(
array('00', '01', '02', '03'),
array('10', '11', '12', '13'),
array('20', '21', '22', '23'),
);

$row = $arr[0];
$col = $arr[][0];
print_r($row);
print "\n";
print_r($col);
?>

> -----Original Message-----
> From: It flance [mailto:itmaqurfe@yahoo.com]
> Sent: Monday, September 29, 2008 11:04 AM
> To: php-general@lists.php.net
> Subject: [php] extract column from multidimentional array
>
> Hi,
>
> below you will find the code for a small script where i'm able to
> extract a row but not a column.
>
> So the question is how can I do that.
>
> Here is the code:
>
> <?php
>
> $arr = array(
> array('00', '01', '02', '03'),
> array('10', '11', '12', '13'),
> array('20', '21', '22', '23'),
> );
>
> $row = $arr[0];
> $col = $arr[][0];
> print_r($row);
> print "\n";
> print_r($col);
> ?>

Being that PHP is row-major (like most programming languages), that
won't work. Loop through the array and build a new one out of just the
1st column from every row (or whatever column you're looking for):

<?php
$colarr = array();
for($a = 0; $a < count($arr); $a++) {
$colarr[$a] = $arr[$a][0]
}
print_r($colarr)
?>

HTH,


Todd Boyd
Web Programmer

On Monday 29 September 2008 09:34:10 pm It flance wrote:
> Hi,
>
> below you will find the code for a small script where i'm able to extract a
> row but not a column.
>
> So the question is how can I do that.
>
> Here is the code:
>
> <?php
>
> $arr = array(
> array('00', '01', '02', '03'),
> array('10', '11', '12', '13'),
> array('20', '21', '22', '23'),
> );
>
> $row = $arr[0];
> $col = $arr[][0];
> print_r($row);
> print "\n";
> print_r($col);
> ?>

If you know the column index of the array, you can do it easily.

$row = $arr[0]; // gives you -array('00', '01', '02', '03')

Now use this to get the first column -

<?

for( $i=0; $i <= count($arr); $i++ ) {

$col[$i] = $arr[$i][0];

}

print_r($col);

?>

On Sep 29, 2008, at 11:08 AM, Boyd, Todd M. wrote:

>> -----Original Message-----
>> From: It flance [mailto:itmaqurfe@yahoo.com]
>> Sent: Monday, September 29, 2008 11:04 AM
>> To: php-general@lists.php.net
>> Subject: [php] extract column from multidimentional array
>>
>> Hi,
>>
>> below you will find the code for a small script where i'm able to
>> extract a row but not a column.
>>
>> So the question is how can I do that.
>>
>> Here is the code:
>>
>> <?php
>>
>> $arr = array(
>> array('00', '01', '02', '03'),
>> array('10', '11', '12', '13'),
>> array('20', '21', '22', '23'),
>> );
>>
>> $row = $arr[0];
>> $col = $arr[][0];
>> print_r($row);
>> print "\n";
>> print_r($col);
>> ?>
>
> Being that PHP is row-major (like most programming languages), that
> won't work. Loop through the array and build a new one out of just the
> 1st column from every row (or whatever column you're looking for):
>
> <?php
> $colarr = array();
> for($a = 0; $a < count($arr); $a++) {
> $colarr[$a] = $arr[$a][0]
> }
> print_r($colarr)
> ?>
>
> HTH,
>
> Todd Boyd
> Web Programmer

Or in his original code....

$col = $arr[0][0];

to get the first (element of the first sub array). Think of your array
as this....

$arr = array(
0 => array(0=>'00', 1=>'01', 2=>'02', 3=>'03'),
1 => array(0=>'10', 1=>'11', 2=>'12', 3=>'13'),
2 => array(0=>'20', 1=>'21', 2=>'22', 3=>'23'),
);

Notice the specific keys? That should help in determining which keys
you're looking for.

I'm probably totally off by what you're asking, but Todd's response
hopefully helped you as well. =D

~Philip

On Monday 29 September 2008 10:15:29 pm Philip Thompson wrote:
> On Sep 29, 2008, at 11:08 AM, Boyd, Todd M. wrote:
> >> -----Original Message-----
> >> From: It flance [mailto:itmaqurfe@yahoo.com]
> >> Sent: Monday, September 29, 2008 11:04 AM
> >> To: php-general@lists.php.net
> >> Subject: [php] extract column from multidimentional array
> >>
> >> Hi,
> >>
> >> below you will find the code for a small script where i'm able to
> >> extract a row but not a column.
> >>
> >> So the question is how can I do that.
> >>
> >> Here is the code:
> >>
> >> <?php
> >>
> >> $arr = array(
> >> array('00', '01', '02', '03'),
> >> array('10', '11', '12', '13'),
> >> array('20', '21', '22', '23'),
> >> );
> >>
> >> $row = $arr[0];
> >> $col = $arr[][0];
> >> print_r($row);
> >> print "\n";
> >> print_r($col);
> >> ?>
> >
> > Being that PHP is row-major (like most programming languages), that
> > won't work. Loop through the array and build a new one out of just the
> > 1st column from every row (or whatever column you're looking for):
> >
> > <?php
> > $colarr = array();
> > for($a = 0; $a < count($arr); $a++) {
> > $colarr[$a] = $arr[$a][0]
> > }
> > print_r($colarr)
> > ?>
> >
> > HTH,
> >
> > Todd Boyd
> > Web Programmer
>
> Or in his original code....
>
> $col = $arr[0][0];
>
> to get the first (element of the first sub array). Think of your array
> as this....
>
> $arr = array(
> 0 => array(0=>'00', 1=>'01', 2=>'02', 3=>'03'),
> 1 => array(0=>'10', 1=>'11', 2=>'12', 3=>'13'),
> 2 => array(0=>'20', 1=>'21', 2=>'22', 3=>'23'),
> );
>
> Notice the specific keys? That should help in determining which keys
> you're looking for.
>
> I'm probably totally off by what you're asking, but Todd's response
> hopefully helped you as well. =D
>
> ~Philip

I think he wants to get the whole column.

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