關于Python函數參數傳遞方式的一點探索
by:授客 QQ:1033553122
實踐代碼
#!/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('set_obj: %s id: %s' % (set_obj, id(set_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: ')
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: ')
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: ')
輸出結果

說明:比較main中,function1中接收的對象參數的值,id,不難發現:python中參數傳遞都是按“引用”傳遞,而非按“值”傳遞。
說明:對比,main,function1中參數對象被修改前,修改後的值,id,不難發現:當執行
var_name = value
語句時,實際把一個新的對象,指派給左側的var_name變量,,指派後
id(var_name) = id(value),,更加有力的說明python中一切皆對象。
說明:對比main,function2中參數對象被修改前,修改後的值,不難發現:當僅修改可變對象的組成項的值時,而不是直接對整個對象指派的情況下,修改的是本對象自身。
作者:授客
QQ:1033553122
全國軟體測試QQ交流群:7156436
Git位址:https://gitee.com/ishouke
友情提示:限于時間倉促,文中可能存在錯誤,歡迎指正、評論!
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