php undefined offset 150 error in for loop

Question

I keep getting an undefined offset 150 error, but i am not sure what it means or what i should do to debug it. Do to the error line i believe that it has something to do with my for loop.

// Get Datafile
$MyData = file("./tmp/test.txt");
// Get Column Headers

$ColHeads = explode("   ", $MyData[1]);

unset($MyData[1]);
$LastHeader = "";
for ($i = 0;$i <= count($ColHeads);$i++) {
    if ($ColHeads[$i] == $LastHeader) { //<---this is the line that errors
        $ColHeads[$i] = $ColHeads[$i] . "1";
    }
    $LastHeader = $ColHeads[$i];
}

Would anyone have any ideas as to where I am going wrong?

and the error is:

Undefined offset: 150

I am sorry if this is vague. I am not familiar with php and not sure where to start on debugging this... any help would be much appreciated! Thank you!

Surreal Dreams · Accepted Answer · 2014-04-08 20:20:27Z

2

Change your for loop:

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

The problem is that on the last iteration of the loop, when $i == count($ColHeads), that's going to set $i too high for the number of items in $ColHeads.

You started off right by setting $i = 0. If $ColHeads has 5 items in it, those items have indexes from 0 to 4. Your for loop, as it is, goes up to 5 - and there is no $Colheads[5], so the error is thrown.

answered Apr 8, 2014 at 20:20

Surreal Dreams

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3 Comments

scapegoat17 Over a year ago

Thank you!, This was really helpful. I will mark this as the answer as soon as SO lets me.

Surreal Dreams Over a year ago

You're very welcome. I added a little more explanation as to why there was a problem. You were most of the way there - you started the index at zero, you just needed to stop looping before you got to count($ColHeads).

Abhik Chakraborty Over a year ago

As a side note u should avoid count() in the loop statement rather do it outside as $cnt = count($ColHeads); and use it in loop for ($i = 0;$i < $cnt;$i++). Think if u have a really big array and u are calling count() on each iteration...

Sabuj Hassan · Accepted Answer · 2014-04-08 20:20:43Z

2

Array index starts from zero. And ends at Length-1. So it should be:

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

answered Apr 8, 2014 at 20:20

Sabuj Hassan

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