PHP - exec awk or fread faster for reading a column on very large file -

i have file containing plot data. each line has 4 coordinates in total data file can exceed 1 gb. let's say, third column in data file, method should consider practice , faster?

using execute:

exec("awk '{ print $3 }' data", $output); 

using php script:

$data = file("data"); $points = array(); foreach($data $line)     $points[] = $line[2]; 

moreover, since server not allow read large file, have use fread read file in several parts. fread not smart enough , work must done combine last line in each part. suggestion or better method read column on file in php?

here /file 3.1 gb big file:

root# time awk '{ print $3 }' /file >/dev/null  real   1m42.430s user   1m0.241s sys    0m2.198s 

okay. ±1.7 minutes awk. let's test php (without field splitting, third char):

root# time php -r '$fp = fopen("/file", "r"); while (($buf = fgets($fp)) !== false) echo $buf[2]; fclose($fp);' >/dev/null  real   4m17.322s user   3m16.571s sys    0m31.625s 

±4.3 minutes php! don't want imagine how long take if i'd use @jack's code...

php far slower awk. on big files, use awk (invoked exec()). see here, php spends lot of time in user space (three times more awk).