Best way to compress string in PHP [duplicate]

Answer 1

How good the compression of your string will be depends on the data you want to compress. If it consists mainly of random data you won't achieve that much improvements in size. There are many algorithms out there which have been designed for specific usage.

You should try to determine what your data to compress mainly consists of and then select a proper compression.

Just now I can only refer you to bzcompress, bzip has usually highter compression rates than gzip.

Answer 2

Im not sure your numbers are right, tho you could use gzdeflate instead of gzcompress as gzcompress adds 6 bytes to the output (2 extra bytes at the beginning and 4 extra bytes at the end).

A simple test shows a 1756800 length string compressed to 99 bytes by double compressing it, 5164 bytes if compressed once.

$string = str_repeat('1234567890' . implode('', range('a', 'z')), 48800);

echo strlen($string); //1756800 bytes

$compressed = gzdeflate($string,  9);
$compressed = gzdeflate($compressed, 9);

echo strlen($compressed); //99 bytes

echo gzinflate(gzinflate($compressed));