Looping through and clearing arrays - php

Question

I have arrays within arrays, all with varying amounts of information. My CSV table currently has the fields Name, Email, and Phone Number.
Below is my array;
Array
(
[0] => Array
(
[0] => Name
[1] => Email
[2] => Phone Number
)
[1] => Array
(
[0] => Mick
[1] => mick#mick.com
[2] => 01234 324234
)
[2] => Array
(
[0] => james
[1] => james#james.com
[2] =>
)
[3] => Array
(
[0] => reg
[1] => reg#reg.com
[2] => 10293 467289
)
)
I wish to loop through and remove these null values and combine the Email and Phone Number into Info end up with an array which resembles
Array
(
[0] => Array
(
[0] => Name
[1] => Info
)
[1] => Array
(
[0] => Mick
[1] => mick#mick.com + 01234 324234
)
[2] => Array
(
[0] => james
[1] => james#james.com
)
[3] => Array
(
[0] => reg
[1] => reg#reg.com + 10293 467289
)
)
Here is my current script, I am recienving the error;
<b>Warning</b>: array_filter() expects parameter 2 to be a valid callback, no array or string given in <b>C:\Users\Lydia\Documents\XAMPP\htdocs\CSV.php</b> on line <b>21</b><br />
every time that I loop through the changeRow() function, any help greatly appreciated
index.php
<?php
include 'CSV.php';
header('Content-type: text/plain');
$file = read_csv('Book1.csv');
$input = changeRow($file);
CSV.php
....
....
function changeRow($rows){
$len = count($rows);
for($i = 0; $i < $len; $i++){
$rows = array_filter($rows[0],0);
}
}

Answer 1

Can use array_map() instead of foreach(). Example:
$file = read_csv('Book1.csv');
$input = array_map(function($v){
$phone = (isset($v[2]) && $v[2]) ? ' + '. $v[2] : '';
return array($v[0], $phone);
},$file );
if(isset($result[0][1])) $result[0][1] = 'Info';
print '<pre>';
print_r($input);
print '</pre>';

Answer 2

I'll provide two methods that output the requested array structure. (PHP Demo Link) These methods iterate the array, check if the iteration is dealing with the "column heading" subarray or not, then conditionally appending the value from subarray element [2] to subarray element [1] using + as glue.
Method #1: foreach()
foreach($array as $index=>$item){
if(!$index){
$result[]=['Name','Info'];
}else{
$result[]=[$item[0],$item[1].(strlen($item[2])?" + $item[2]":'')];
}
}
var_export($result);
Method #2 array_map()
var_export(
array_map(function($index,$item){
if(!$index){
return ['Name','Info'];
}else{
return [$item[0],$item[1].(strlen($item[2])?" + $item[2]":'')];
}
},array_keys($array),$array)
);
Output: (from either method)
array (
0 =>
array (
0 => 'Name',
1 => 'Info',
),
1 =>
array (
0 => 'Mick',
1 => 'mick#mick.com + 01234 324234',
),
2 =>
array (
0 => 'james',
1 => 'james#james.com',
),
3 =>
array (
0 => 'reg',
1 => 'reg#reg.com + 10293 467289',
),
)
ps. If you want to remove the $index==0 check that is iterated each time, you can manually overwrite the first subarray after the loop is finished like this: (PHP Demo Link) *this just means you will be "writing" data to the first subarray twice.
foreach($array as $item){
$result[]=[$item[0],$item[1].(strlen($item[2])?" + $item[2]":'')];
}
$result[0]=['Name','Info'];
var_export($result);
or
$result=array_map(function($item){return [$item[0],$item[1].(strlen($item[2])?" + $item[2]":'')];},$array);
$result[0]=['Name','Info'];
var_export($result);
pps. "Passing by Reference" can be used for this task, but I've elected not to use &$array because it can risk causing trouble "downscript" and many developers advise against using it until other methods are inadequate. Here is what that can look like: (PHP Demo Link)
foreach($array as &$item){
if(strlen($item[2])) $item[1].=" + $item[2]";
unset($item[2]);
}
$array[0]=['Name','Info'];
var_export($array);
unset($item); // var_export($item); // ($item = NULL)