关于Python函数参数传递方式的一点探索
by:授客 QQ：1033553122
实践代码
#!/usr/bin/env python
# -*- coding:utf-8 -*-
__author__ = 'laifuyu'
def function1(int_obj, float_obj, str_obj, boolean_obj, list_obj, tuple_obj, set_obj, dict_obj):
print('\nvalue of args of function1: ')
print('int_obj: %s id:%s' % (int_obj, id(int_obj)))
print('float_obj: %s id:%s' % (float_obj, id(float_obj)))
print('str_obj: %s id:%s' % (str_obj, id(str_obj)))
print('boolean_obj: %s id:%s' % (boolean_obj, id(boolean_obj)))
print('list_obj: %s id:%s' % (list_obj, id(list_obj)))
print('tuple_obj: ',tuple_obj, ' id: ', id(tuple_obj))
print('set_obj: %s id: %s' % (set_obj, id(set_obj)))
print('dict_obj: %s id: %s' % (dict_obj, id(dict_obj)))
int_obj = 8
float_obj = 9.0
str_obj = 'ishouke'
boolean_obj = True
list_obj = ['i', 'shou', 'ke']
tuple_obj = ('shou', 'ke', '2014')
set_obj = {'shouke', '2014'}
dict_obj = {'time':2014, 'author':'shouke'}
print('\nvalue of obj after value changed in function1: ')
print('int_obj: %s id:%s' % (int_obj, id(int_obj)))
print('float_obj: %s id:%s' % (float_obj, id(float_obj)))
print('str_obj: %s id:%s' % (str_obj, id(str_obj)))
print('boolean_obj: %s id:%s' % (boolean_obj, id(boolean_obj)))
print('list_obj: %s id:%s' % (list_obj, id(list_obj)))
print('tuple_obj: ',tuple_obj, ' id: ', id(tuple_obj))
print('set_obj: %s id: %s' % (set_obj, id(set_obj)))
print('dict_obj: %s id: %s' % (dict_obj, id(dict_obj)))
def function2(list_obj, tuple_obj, set_obj, dic_obj):
list_obj[2] = '2014'
tuple_obj[2][0] = '2016'
set_obj.add('2014')
dict_obj['time'] = 2014
print('\nvalue of obj after value changed in function2: ')
print('list_obj: %s id:%s' % (list_obj, id(list_obj)))
print('tuple_obj: ',tuple_obj, ' id: ', id(tuple_obj))
print('set_obj: %s id: %s' % (set_obj, id(set_obj)))
print('dict_obj: %s id: %s' % (dict_obj, id(dict_obj)))
if __name__ == '__main__':
int_obj = 6
float_obj = 7.0
str_obj = 'shouke'
boolean_obj = False
list_obj = ['shou', 'ke', 'python']
tuple_obj = ('shou', 'ke', ['2014'])
set_obj = {'i', 'shouke'}
dict_obj = {'time':2016, 'author':'ishouke'}
print('value of obj in main before function1 called: ')
print('int_obj: %s id:%s' % (int_obj, id(int_obj)))
print('float_obj: %s id:%s' % (float_obj, id(float_obj)))
print('str_obj: %s id:%s' % (str_obj, id(str_obj)))
print('boolean_obj: %s id:%s' % (boolean_obj, id(boolean_obj)))
print('list_obj: %s id:%s' % (list_obj, id(list_obj)))
print('tuple_obj: ',tuple_obj, ' id: ', id(tuple_obj))
print('set_obj: %s id: %s' % (set_obj, id(set_obj)))
print('dict_obj: %s id: %s' % (dict_obj, id(dict_obj)))
function1(int_obj, float_obj, str_obj, boolean_obj, list_obj, tuple_obj, set_obj, dict_obj)
print('\nvalue of obj in main after function1 called: ')
print('int_obj: %s id:%s' % (int_obj, id(int_obj)))
print('float_obj: %s id:%s' % (float_obj, id(float_obj)))
print('str_obj: %s id:%s' % (str_obj, id(str_obj)))
print('boolean_obj: %s id:%s' % (boolean_obj, id(boolean_obj)))
print('list_obj: %s id:%s' % (list_obj, id(list_obj)))
print('tuple_obj: ',tuple_obj, ' id: ', id(tuple_obj))
print('set_obj: %s id: %s' % (set_obj, id(set_obj)))
print('dict_obj: %s id: %s' % (dict_obj, id(dict_obj)))
function2(list_obj, tuple_obj, set_obj, dict_obj)
print('\nvalue of obj in main after function2 called: ')
print('list_obj: %s id:%s' % (list_obj, id(list_obj)))
print('tuple_obj: ',tuple_obj, ' id: ', id(tuple_obj))
print('set_obj: %s id: %s' % (set_obj, id(set_obj)))
print('dict_obj: %s id: %s' % (dict_obj, id(dict_obj)))
输出结果
说明：比较main中，function1中接收的对象参数的值，id，不难发现：python中参数传递都是按“引用”传递，而非按“值”传递。
说明：对比，main，function1中参数对象被修改前，修改后的值，id，不难发现：当执行
var_name = value
语句时，实际把一个新的对象，赋值给左侧的var_name变量，，赋值后
id(var_name) = id(value),,更加有力的说明python中一切皆对象。
说明：对比main，function2中参数对象被修改前，修改后的值，不难发现：当仅修改可变对象的组成项的值时，而不是直接对整个对象赋值的情况下，修改的是本对象自身。