PHP Array Undefined index error issues even when I can see the array output

Question

I have an numeric index array here is a portion of the print_r:

Array
(
    [0] => Array
        (
            [from_stop_id] => 1
            [to_stop_id] => 1
            [transfer_type] => 1
            [min_transfer_time] => 
        )

    [1] => Array
        (
            [from_stop_id] => 3
            [to_stop_id] => 3
            [transfer_type] => 1
            [min_transfer_time] => 
        )

    [2] => Array
        (
            [from_stop_id] => 4
            [to_stop_id] => 4
            [transfer_type] => 1
            [min_transfer_time] => 
        )
)

here is my php loop:

for ( $counter = 0; $counter < count($transfers_csv); $counter++) {
    echo $transfers_csv[$counter]['from_stop_id'];
    echo $transfers_csv[$counter]['to_stop_id'];
    echo  $transfers_csv[$counter]['transfer_type']; 
    echo $transfers_csv[$counter]['min_transfer_time'];
}

here is my error output:

Notice: Undefined index: from_stop_id in C:\MAMP\htdocs\wp50\wp-content\plugins\tm-gtfs-data\tm-gtfs-data.php on line 453
11
Notice: Undefined index: from_stop_id in C:\MAMP\htdocs\wp50\wp-content\plugins\tm-gtfs-data\tm-gtfs-data.php on line 453
31
Notice: Undefined index: from_stop_id in C:\MAMP\htdocs\wp50\wp-content\plugins\tm-gtfs-data\tm-gtfs-data.php on line 453
41

I cannot understand WHY it is giving me an undefined index when I know the following. $transfers_csv is AN Numeric Indexed Array. I can see from the output that there are values for 'from_stop_id', for 'to_stop_id' and 'transfer_type' but 'min_transfer_type' value is empty or NULL.

Anyone see what I am doing wrong here??

Are you sure key 11, 31 and 41 exist? Why not make it simple and use foreach? `here is a portion of the print_r` expand that example to past key 12. — Andreas, Oct 29 '19 at 17:14
did you try var_dumping `$transfers_csv[$counter]` to ensure it's holding the data you're expecting? — treyBake, Oct 29 '19 at 17:14
Possible duplicate of ["Notice: Undefined variable", "Notice: Undefined index", and "Notice: Undefined offset" using PHP](https://stackoverflow.com/questions/4261133/notice-undefined-variable-notice-undefined-index-and-notice-undefined) — aynber, Oct 29 '19 at 17:15
@trey you mean `$transfers_csv`? $counter is an integer of the for loop — Andreas, Oct 29 '19 at 17:15
@Andreas nah, as `$transfers_csv[$counter]` should show an array with the key == counter - though, as you've said, it would be easier (for everyone) if a foreach was used here^^ — treyBake, Oct 29 '19 at 17:18

score 4 · Accepted Answer · answered Oct 29 '19 at 17:33

You are obviously reading the headers from a csv file and mistakenly including the the BOM (Byte Order Mark) in the first header from_stop_id.

So from_stop_id is actually \uFEFFfrom_stop_id, that's why PHP is throwing the an undefined index notice.

Read more about it here: https://en.wikipedia.org/wiki/Byte_order_mark

Not sure if you're using fgetscsv() but it's known that this function have problems when dealing with the BOM.

If you have control over the csv file you can save it without including the BOM.

It's possible to deal with this on your code alos, one way would be something like:

$fp = fopen($path, 'r');

if (fgets($fp, 4) !== "\xef\xbb\xbf") {
    rewind($fp);
}

// call fgetcsv() as usual

PHP Array Undefined index error issues even when I can see the array output

1 Answers1