PHP freezes when adding to array in while loop - php

Question

I have a 260k line csv file that has two columns. I have read in the csv file using fgetcsv and have a while loop which reads every line in the file. In the loop I am trying to add the values from the second column to an array.
When I have the line in to add to the array, my PHP freezes and doesn't finish. I have done debugging and the values are getting added to the array so I know that the adding to array and while loop work but I do not know why it freezes.
If I remove the line the while loop completes going through the 260k lines and then processes the rest of the file.
Here is my code:
$amountRecords = 0;
$totalValue = 0;
$valueArray = array();
// reads in csv file
$handle = fopen('Task1-DataForMeanMedianMode.csv', 'r');
// to skip the header names/values
fgetcsv($handle);
// creates array containing variables from csv file
while(($row = fgetcsv($handle, "\r")) != FALSE)
{
/*
echo "ROW CONTAINS: ";
var_dump($row[1]);
echo "<br />";
*/
$valueArray[] = $row[1];
/*
echo "VALUEARRAY NOW CONTAINS: ";
var_dump($valueArray);
echo "<br />";
*/
$totalValue = $totalValue + $row[1];
$amountRecords++;
}
And sample of csv file:
ID,Value
1,243.00
2,243.00
3,243.00
4,243.00
5,123.11
6,243.00
7,180.00
8,55.00
9,243.00
10,55.00

Answer 1

With an out-of-memory error, there are two general approaches. As usual with these choices, you can pick easy-but-wrong and hard-but-right. The easy-but-wrong solution is to increase your memory limit to an appropriate level:
ini_set('memory_limit', '64M');
the better (although harder) solution is to re-engineer your algorithm to not need as much memory. This is clearly the more sustainable and robust approach. To do this properly, you will need to evaluate what you need to do with the array you are building. For instance, I have written similar scripts which were importing the rows to a database. Instead of building a huge array and then inserting, I did it in batches, where I built an array of 50-100 rows, then inserted those and cleared the array (freeing the memory for re-use).
Pseudo-code:
for(each row in file) {
$rows_cache[] = $row[1];
if(count($rows_cache) >= 50) {
insert_these($rows_cache);
$rows_cache = array();
}
}

Answer 2

Your first row is string, maybe try adding
while(($row = fgetcsv($handle, "\r")) != FALSE)
{
if(is_numeric($row[1]))
{
$valueArray[] = $row[1];
$totalValue = $totalValue + $row[1];
$amountRecords++;
}
}

Answer 3

Why not drop the line:
$totalValue = $totalValue + $row[1];
from inside your loop, and instead use:
$totalValue = array_sum($valueArray);
after completing your loop

Answer 4

Not really the problem, but
while(($row = fgetcsv($handle, "\r")) != FALSE)
can be rewritten as
while($row = fgetcsv(...))
instead. There's no need for the explicit false check - if fgetcsv returns false, the while loop would terminate anyways. Plus this version is more legible, and not as risky. If you forget the () around the fget portion, you'll be doing the equivalent of $row = (fgetcsv() != false) and simply getting a boolean value.