python - 计算不包括空格的字符数 - python

Question

哪种方法可以更快地计算没有空格的字符数？ 哪个更Pythonic？

def sent_length(sentence):
  return sum(1 for c in sentence if c != ' ')

或

def sent_length(sentence):
  return len(sentence.replace(" ", ""))

或

import re 
pattern = re.compile(r'\s+')

def sent_length(sentence):
  return len(re.sub(pattern, '', sentence))

Answer 1

您可以从python -m timeit获取计时:

[matt tmp] python -m timeit "sum(1 for c in 'blah blah blah' if c != ' ')"
100000 loops, best of 3: 2.96 usec per loop
[matt benchmark] python -m timeit -s "import re; pattern = re.compile(r'\s+')" "len(pattern.sub('', 'blah blah blah'))"
100000 loops, best of 3: 2.2 usec per loop
[matt tmp] python -m timeit "len(''.join('blah blah blah'.split()))"
1000000 loops, best of 3: 0.785 usec per loop
[matt tmp] python -m timeit "len('blah blah blah'.replace(' ', ''))"
1000000 loops, best of 3: 0.437 usec per loop
[matt tmp] python -m timeit "len('blah blah blah') - 'blah blah blah'.count(' ')"
1000000 loops, best of 3: 0.384 usec per loop

这将帮助您确定什么是最快的。更Python化？我会选择最快的，因为性能总是很重要。