python 通过字符串调用对象属性或方法

In [634]: def getmethod(x,char='just for test'):
  ...:  return eval('str.%s' % x)(char)
  ...:

In [635]: getmethod('upper')
Out[635]: 'JUST FOR TEST'

In [650]: def getmethod2(x, char='just for test'):
  ...:  return getattr(char, x)()
  ...:

In [651]: getmethod2('upper')
Out[651]: 'JUST FOR TEST'

In [648]: def getmethod3(x, char='just for test'):
  ...:  return operator.methodcaller(x, char)(str)
  ...:

In [649]: getmethod3('upper')
Out[649]: 'JUST FOR TEST'