Reference and copy of Python first-time experience objects

All those who have written about Java know that the reference of this object and object clone are completely unnecessary. As an object-oriented language, Python is not an example, most of his declaration or use of a variable is a reference to the object, but occasionally we will have to use the object clone, next, let's take an example to illustrate the differences between the object clone and object reference. This is very important. First, let's take a look at the code [python] ''' Created on 2013-1-25 @ author: Administrator ''' shoplist = ['apple', 'mango', 'carrot ', 'bana'] mylist = shoplist del shoplist [0] print ("shoplist is", shoplist) print ("mylist is", mylist) # copy mylist = shoplist [:] del shoplist [0] print ("shoplist is", shoplist) print ("mylist is", mylist) ''' Created on 2013-1-25 @ author: administrator ''' shoplist = ['apple', 'mango', 'carrot', 'bana Na '] mylist = shoplist del shoplist [0] print ("shoplist is", shoplist) print ("mylist is", mylist) # copy mylist = shoplist [:] del shoplist [0] print ("shoplist is", shoplist) print ("mylist is", mylist) Outputs [python] shoplist is ['mango ', 'carrot', 'bana'] mylist is ['mango', 'carrot', 'bana'] shoplist is ['carrot ', 'bana'] mylist is ['mango', 'carrot', 'Banana '] shoplist is ['mango', 'carrot', 'Banana '] Mylist is ['mango', 'carrot', 'bana'] shoplist is ['carrot', 'bana'] mylist is ['mango', 'carrot ', 'banana '] You can clearly understand the concept of reference to this sequence and object clone. You need to be familiar with clone of this sequence ., Shoplist [:] is not always used, but mark it