pr119.py

来自「mallet是自然语言处理、机器学习领域的一个开源项目。」· Python 代码 · 共 17 行

d = {}
l = [1]
try:
    d[l] = 2
except TypeError:
    pass
else:
    print 'Should not be able to use a list as a dict key!'

a = {}
try:
    d[a] = 2
except TypeError:
    pass
else:
    print 'Should not be able to use a dict as a dict key!'