在实际写程序中，经常要对变量类型进行判断，除了用type(变量)这种方法外，还可以用isinstance方法判断：
#!/usr/bin/env python
a = 1
b = [1,2,3,4]
c = (1,2,3,4)
d = {‘a‘:1,‘b‘:2,‘c‘:3}
e = "abc"
if isinstance(a,int):
print "a is int"
else:
print "a is not int"
if isinstance(b,list):
print "b is list"
else:
print "b is not list"
if isinstance(c,tuple):
print "c is tuple"
else:
print "c is not tuple"
if isinstance(d,dict):
print "d is dict"
else:
print "d is not dict"
if isinstance(e,str):
print "d is str"
else:
print "d is not str"