python 可变不可变类型

# -*- coding: utf-8 -*-var1 = 1var2 = var1print var1, var2print id(var1), id(var2)print '============'var1 += 1print var1, var2print id(var1), id(var2)print '============'t1 = (1, 2, 3)t2 = t1print t1, t2print id(t1), id(t2)print '============'s1 = 'hello's2 = s1s3 = s1.lower()print s1, s2, s3print id(s1), id(s2), id(s3)print '\n++++++++++++++++++++++++++++\n'l1 = [1, 2, 3]l2 = l1print l1, l2print id(l1), id(l2)l1.append(4)print l1, l2print id(l1), id(l2)print '============'d1 = {'k1': 1}d2 = d1d1['k2'] = 2print d1, d2print id(d1), id(d2)print '============'def dis(arg=[]):    arg.append('1')    print arg    dis()dis()dis()

原文：http://blog.chinaunix.net/uid-26249349-id-3080279.html