python 可变不可变类型

# -*- coding: utf-8 -*-

var1 = 1
var2 = var1
print var1, var2
print id(var1), id(var2)
print '============'

var1 += 1
print var1, var2
print id(var1), id(var2)
print '============'

t1 = (1, 2, 3)
t2 = t1
print t1, t2
print id(t1), id(t2)
print '============'

s1 = 'hello'
s2 = s1
s3 = s1.lower()
print s1, s2, s3
print id(s1), id(s2), id(s3)
print '\n++++++++++++++++++++++++++++\n'

l1 = [1, 2, 3]
l2 = l1
print l1, l2
print id(l1), id(l2)
l1.append(4)
print l1, l2
print id(l1), id(l2)
print '============'

d1 = {'k1': 1}
d2 = d1
d1['k2'] = 2
print d1, d2
print id(d1), id(d2)
print '============'

def dis(arg=[]):
arg.append('1')
print arg

dis()
dis()
dis()