Loop through PHP array based on index

Question

How can I assign values to an array of strings using an index? Let's say I don't know what the values of the strings are in the array, so I use keys instead.

Array that could be any list of strings:

$this->cols = array(
    'name',
    'age'
);

assignment function

$row = 1;
        if (($f = fopen($this->file['tmp_name'], "r")) !== FALSE) {
          while (($data = fgetcsv($f, 0, ",")) !== FALSE) {
                $num = count($data);
                $row++;
                for ($c=0; $c < $num; $c++) {
                    $colName = $this->cols[$c];
                    $this->cols[$colName] = $data[$c];
                }
            }

How can I assign the value ($data[$c]) to the corresponding index if I don't supply its value, but rather use a numerical index? I know for a fact that I can access the array like this because

$colName[0] = 'name'
$colName[1] = 'age'

But when I run the function I get

0 => nameValue
1 => ageValue

Instead of

'name' => nameValue
'age' => ageValue

I suggest you start looking into the php documentation. There you will find a wealth of array handling functions. All explained in details including examples. — arkascha
– arkascha, Commented Jan 10, 2015 at 18:37
The main problem I see is too many things happening at the same time. Try to separate the part where you read the file from the loop of it, then the assignment of the variables from the loop. In this way every bug/problem will be much easier to spot. — Francisco Presencia
– Francisco Presencia, Commented Jan 10, 2015 at 19:09

cwallenpoole · Accepted Answer · 2015-01-10 18:39:36Z

1

You're overwriting your own data:

 $num = count($data);
 $row++;
 for ($c=0; $c < $num; $c++) {
     // every row of the CSV will update the same keys
     $colName = $this->cols[$c];
     $this->cols[$colName] = $data[$c];

 }

 // I suggest adding a `break` after that for look to see the problem.
 break;

Alternatively, you could update the code to track all values:

 $num = count($data);
 $row_val = array();
 $this->cols[] = $row_val;
 $row++;
 for ($c=0; $c < $num; $c++) {
     // every row of the CSV will update the same keys
     $colName = $this->col_names[$c];
     $row_val[$colName] = $data[$c];

 }

answered Jan 10, 2015 at 18:39

cwallenpoole

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3 Comments

user3822370 Over a year ago

You're probably right but I haven't gotten that far yet. I just wanted to understand how to assign a value to an array based on indexes.

user3822370 Over a year ago

OK so the answer is make a new array to assign the values. Thanks.

Riad Over a year ago

actually the OP was not overriding..he was appending to the array. when i ran this code i got 4 elements with 0,1,name, age keys.

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