引用（reference）

知识点： 列表的赋值语句不创建拷贝。得使用切片操作符来建立序列的拷贝。 C:\Windows\System32>pythonPython 3.2 (r32:88445, Feb 20 2011, 21:29:02) [MSC v.1500 32 bit (Intel)] on win32Type "help", "copyright", "credits" or "license" for more information.>>> MyLang = ['C', 'C++', 'Python']>>> MyLang_1 = MyLang>>> del(MyLang[0])>>> print(MyLang)['C++', 'Python']>>> print(MyLang_1)['C++', 'Python']>>> MyLang_2 = MyLang[:]>>> del(MyLang[0])>>> print(MyLang)['Python']>>> print(MyLang_2)['C++', 'Python']>>> # MyLang_1 is just another name pointing to the same object!...>>> # MyLang_2 is a copy of MyLang by doing full slice...>>> # This is called reference....>>>