PHP Export Indexed Array into CSV [duplicate] - php

Question

This question already has answers here:
Add elements to array which has gapped numeric keys to form an indexed array / list
(5 answers)
Closed 5 months ago.
I have a following indexed array
$export_data = array (
[0] => 1,
[1] => 2,
[2] => 3,
[3] => 4,
[4] => 5,
[8] => 9,
[9] => 10,
);
I know how to export it to csv using fputcsv. However what my issue is that I need to export the data into correct column i.e. value in $export_data[8] needs to be exported in column 9 not column 6.
How can this be done please ?

Answer 1

Here you go, boss.
$export_data = array_replace(array_map(function($v){return null;}, range(0, max(array_keys($export_data)))), $export_data);
Tested 100,000 iterations and results are in seconds:
Version Run1 Run2 Run3
PHP 5.6.20 .58 .55 .50
PHP 7.0.5 .18 .21 .21
Now for the explanation so I don't get flogged with downvotes or get accused of witchcraft.
$export_data = array (
0 => 1,
1 => 2,
2 => 3,
3 => 4,
4 => 5,
8 => 9,
9 => 10,
);
$export_data =
array_replace( // replace the elements of the 10-item array with your original array and the filled-in blanks are going to be null. I did not use array_merge() because it would append $export_data onto our dynamic range() array rather than replacing elements as needed.
array_map( // loop the 10-item array and apply the declared function per element. This function ends up returning the 10-item array with all keys intact but the values will be null
function($v){return null; /* return ''; // if you prefer and empty string instead of null*/}, // set each value of the 10-item array to null
range( // create an 10-item array with indexes and values of 0-9
0,
max(array_keys($export_data)) // get the highest key of your array which is 9
)
),
$export_data // your original array with gaps
);
var_dump($export_data);
print_r($export_data);

Answer 2

if i understand correctly, you want to put free columns between data, so the keys match column number.
$arr = array(
0 => 1,
1 => 2,
2 => 3,
3 => 4,
4 => 5,
8 => 9,
9 => 10,
);
$csvArray = array();
$maxKey = max(array_keys($arr));
for($i = 0; $i <= $maxKey; $i++){
if(array_key_exists($i, $arr)){
$csvArray[$i] = $arr[$i];
} else {
$csvArray[$i] = null;
}
}
print_r($csvArray);
demo here: live demo
to describe it, just cycle through array and check wether key is set, if is, assing its value to the next array, if is not, assign null
Optimized:
$csvArray = array();
$maxKey = max(array_keys($arr));
// ++$i is microscopically faster when going for the long haul; such as 10,000,000 iterations
// Try it for yourself:
// $start = microtime(true);
// for($i=0; $i<10000000; $i++){}
// echo (microtime(true) - $start).' seconds';
for($i = 0; $i <= $maxKey; ++$i){
// we can use isset() because it returns false if the value is null anyways. It is much faster than array_key_exists()
$csvArray[$i] = (isset($arr[$i]) ? $arr[$i] : null);
}

Answer 3

I would just fill the array completely with empty values for the empty columns:
$export_data = array (
[0] => 1,
[1] => 2,
[2] => 3,
[3] => 4,
[4] => 5,
[5] => '',
[6] => '',
[7] => '',
[8] => 9,
[9] => 10,
);
Without the indexes (because they are automatic in any case):
$export_data = array (
1,
2,
3,
4,
5,
'',
'',
'',
9,
10,
);