python id 運(yùn)算符
#!/usr/bin/python
a = 20
b = 20
if ( a is b ):
? print "Line 1 - a and b have same identity"
else:
? print "Line 1 - a and b do not have same identity"
if ( id(a) == id(b) ):
? print "Line 2 - a and b have same identity"
else:
? print "Line 2 - a and b do not have same identity"
b = 30
if ( a is b ):
? print "Line 3 - a and b have same identity"
else:
? print "Line 3 - a and b do not have same identity"
if ( a is not b ):
? print "Line 4 - a and b do not have same identity"
else:
? print "Line 4 - a and b have same identity"
更多實(shí)例：http://codingdict.com/article/19147
