Python参数传递机制传值和传引用原理详解

from ctypes import *
import os.path 
import sys

def test(c):
  print "test before "
  print id(c)
  c+=2
  print "test after +"
  print id(c)
  return c

def printIt(t):
  for i in range(len(t)):
    print t[i]

if __name__=="__main__":
  a=2
  print "main before invoke test"
  print id(a)
  n=test(a)
  print "main afterf invoke test"
  print a
  print id(a)

>>> 
main before invoke test
test before 
test after +
main afterf invoke test
39601564

>>> a=1
>>> b=1
>>> id(a)
>>> id(b)
>>> a=2
>>> id(a)

from ctypes import *
import os.path 
import sys

def test(list2):
  print "test before "
  print id(list2)
  list2[1]=30
  print "test after +"
  print id(list2)
  return list2

def printIt(t):
  for i in range(len(t)):
    print t[i]

if __name__=="__main__":
  list1=["loleina",25,'female']
  print "main before invoke test"
  print id(list1)
  list3=test(list1)
  print "main afterf invoke test"
  print list1
  print id(list1)

>>> 
main before invoke test
test before 
test after +
main afterf invoke test
['loleina', 30, 'female']

>>> list1=[1,2]
>>> id(list1)
>>> list1[0]=[0]
>>> list1
[[0], 2]
>>> id(list1)

>>> def fun2(num1,l1,d1):
...   num1=123
...   l1[0]=123
...   d1['a']=123
...   print("inside:","num1=%f,l1=%s,d1=%s"%(num1,l1,d1))
... 
>>> num=111
>>> l=[1,1,1]
>>> d={'a':111,'b':0}
>>> print("before:","num=%f,l=%s,d=%s"%(num,l,d))
before: num=111.000000,l=[1, 1, 1],d={'a': 111, 'b': 0}
>>> fun2(num,l,d)
inside: num1=123.000000,l1=[123, 1, 1],d1={'a': 123, 'b': 0}
>>> print("after:","num=%f,l=%s,d=%s"%(num,l,d))
after: num=111.000000,l=[123, 1, 1],d={'a': 123, 'b': 0}