For comparison, PHP has mutable strings. Some totally unscientific averaged benchmarks (Atom D2700, PHP 5.4.4-14 amd64): $buff = ''; for ($i = 0; $i !=

For comparison, PHP has mutable strings. Some totally unscientific averaged benchmarks (Atom D2700, PHP 5.4.4-14 amd64): $buff = ''; for ($i = 0; $i != 100000; ++$i) { $buff .= $i; } Runs in about 0.06s $buff = array(); for ($i = 0; $i != 100000; ++$i) { $buff[] = $i; } $ret = implode('', $buff); Runs slower, in about 0.10s $ret = implode('', range(0, 100000)); Takes roughly the same time, 0.10s