[Python]with statement

with statement is very helpful in Python code not to forget close in file, for example. We can define it following a rule as below. Nice. We can build our with to make some process safe. This is a note for me.

class WithClass(object):
  def __init__(self):
    print('init')

  def neko(self):
    print('neko')

  def __enter__(self):
    print('enter')
    return self

  def __exit__(self, ex_type, ex_value, trace):
    print('exit: {}, {}, {}'.format(ex_type, ex_value, trace))

def creator():
  return WithClass()

with creator() as w:
  w.neko()

• https://docs.python.org/3/reference/datamodel.html#with-statement-context-managers
• https://www.python.org/dev/peps/pep-0343/
• http://effbot.org/zone/python-with-statement.htm