read large js array from a file using PHP

Question

I'm trying to process a large(150MB+) JavaScript array from a CSV file.

Here is what the array looks like:

var results = [
{"requestId":"1","responseId":"1","time":"11","opacity":"0.6"}
,
{"requestId":"1","responseId":"2","time":"12","opacity":"0.7"}
,
{"requestId":"1","responseId":"3","time":"13","opacity":"0.8"}
,
{"requestId":"1","responseId":"4","time":"14","opacity":"0.9"}
,
{"requestId":"1","responseId":"5","time":"15","opacity":"0.1"}
....
];

There are about 100,000 lines. I need to take each of the values from each of the array elements.

For instance, I need to take 1, 1, 11 and 0.6 from "requestId", "responseId", "time" and "opacity" respectively.

I've tried to use *file_get_contents* (failed, couldn't read the file, it is too big), and file stream, also the following code to read, but i don't know how to extract the numbers using PHP. Thanks so much for your help. Is there anyway that I can convert this into PHP array or JSON? I like to process the numbers as quick as possible though...

$fh = fopen($cachedFile, 'r');
$Data = fread($fh, filesize($cachedFile));
fclose($fh);
echo "<pre>";
echo $Data;
echo "</pre>";

Why not consider a database that can import json like MongoDB — Baba
– Baba, Commented Mar 29, 2013 at 19:16
Yes you can import json to mysql but not by default see karlssonondatabases.blogspot.se/2012/07/… — Baba
– Baba, Commented Mar 29, 2013 at 19:56

Mostafa Shahverdy · Accepted Answer · 2013-03-29 20:04:46Z

2

failed, couldn't read the file, it is too big

This is a problem with your PHP config file limit. You can change it within php.ini to:

memory_limit = 200M

Or add the following to your PHP script:

ini_set('memory_limit', '200M');

I don't know how to extract the numbers using PHP

In order to get values, you can use something like this:

$fh = fopen('a.txt', 'r');
$Data = fscanf($fh, '{"requestId":"%d","responseId":"%d","time":"%d","opacity":"%f"}');

print_r($Data);

This will output something like this:

Array
(
    [0] => 1
    [1] => 1
    [2] => 11
    [3] => 0.6
)

Note that in the above code, I assumed that your file have multiple lines of '{"requestId":"%d","responseId":"%d","time":"%d","opacity":"%f"}' . You can change it to whatever you want

edited Mar 29, 2013 at 20:04

answered Mar 29, 2013 at 19:04

Mostafa Shahverdy

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3 Comments

led Over a year ago

thanks, i haven't tried this yet, but what I really want to know is how I can get the numbers from the array using PHP....

led Over a year ago

it did not return anything..except that it returned ( [0] => [1] => [2] => [3] => )

Mostafa Shahverdy Over a year ago

As I mentioned in the last line, I assumed that your file have multiple lines of {"requestId":"%d","responseId":"%d","time":"%d","opacity":"%f"}. How does your file really look like ?

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