Python中判断子串存在的性能比较及分析总结

import timeit

def in_(s, other):
  return other in s

def contains(s, other):
  return s.__contains__(other)

def find(s, other):
  return s.find(other) != -1

def index(s, other):
  try:
    s.index(other)
  except ValueError:
    return False
  return True

perf_dict = {
  'in:True': min(timeit.repeat(lambda: in_('superstring', 'str'))),
  'in:False': min(timeit.repeat(lambda: in_('superstring', 'not'))),
  '__contains__:True': min(timeit.repeat(lambda: contains('superstring', 'str'))),
  '__contains__:False': min(timeit.repeat(lambda: contains('superstring', 'not'))),
  'find:True': min(timeit.repeat(lambda: find('superstring', 'str'))),
  'find:False': min(timeit.repeat(lambda: find('superstring', 'not'))),
  'index:True': min(timeit.repeat(lambda: index('superstring', 'str'))),
  'index:False': min(timeit.repeat(lambda: index('superstring', 'not'))),
}

print(perf_dict)

static PyObject *
unicode_find(PyObject *self, PyObject *args)
{
  /* initialize variables to prevent gcc warning */
  PyObject *substring = NULL;
  Py_ssize_t start = 0;
  Py_ssize_t end = 0;
  Py_ssize_t result;

  if (!parse_args_finds_unicode("find", args, &substring, &start, &end))
    return NULL;

  if (PyUnicode_READY(self) == -1)
    return NULL;

  result = any_find_slice(self, substring, start, end, 1);

  if (result == -2)
    return NULL;

  return PyLong_FromSsize_t(result);
}

static PyObject *
unicode_index(PyObject *self, PyObject *args)
{
  /* initialize variables to prevent gcc warning */
  Py_ssize_t result;
  PyObject *substring = NULL;
  Py_ssize_t start = 0;
  Py_ssize_t end = 0;

  if (!parse_args_finds_unicode("index", args, &substring, &start, &end))
    return NULL;

  if (PyUnicode_READY(self) == -1)
    return NULL;

  result = any_find_slice(self, substring, start, end, 1);

  if (result == -2)
    return NULL;

  if (result < 0) {
    PyErr_SetString(PyExc_ValueError, "substring not found");
    return NULL;
  }

  return PyLong_FromSsize_t(result);
}