For anyone else who wants to time the examples without copying & pasting each line: python3 -m timeit -n 1 -r 3 -s "import re ; haystack = (' ' * 20000) +

For anyone else who wants to time the examples without copying & pasting each line: python3 -m timeit -n 1 -r 3 -s "import re ; haystack = (' ' * 20000) + 'a'" -c "re.match('\s+$', haystack)" 1 loops, best of 3: 467 usec per loop python3 -m timeit -n 1 -r 3 -s "import re ; haystack = (' ' * 20000) + 'a'" -c "re.search('\s+$', haystack)" 1 loops, best of 3: 4.23 sec per loop Options -n how many times to execute statement -r how many times to repeat the timer -s setup code (run once) -c command to run n times