引用 （refer)，如果有前幾天看我發(fā)的注意力test矩陣的輸出就應(yīng)該有注意到一個(gè)點(diǎn)就是我在產(chǎn)生隨機(jī)數(shù)就同時(shí)賦值給兩個(gè)數(shù)組。
image.png
這里引用如果只是賦值給另一個(gè)變量，應(yīng)該是地址引用，而不是重新申請(qǐng)一個(gè)地址空間存這個(gè)變量，所以你在對(duì)其中一個(gè)變量在操作時(shí)就會(huì)相互影響。
這點(diǎn)在編程時(shí)一定要注意。
接下來(lái)我們看幾個(gè)例子：
- 賦值 變量mylist=shoplist
- mylist.sort
- mylist.append
- 切片賦值 mylist_slice=shoplist[:]
- 刪除 def mylist_slice[0]
print('Simple Assignment')
shoplist = ['apple', 'mango', 'carrot', 'banana']
# mylist 只是指向同一對(duì)象的另一種名稱
mylist = shoplist
print(mylist)
#['apple', 'mango', 'carrot', 'banana']
print(shoplist)
#['apple', 'mango', 'carrot', 'banana']
#進(jìn)行排序
mylist.sort();
print(mylist)
#['apple', 'banana', 'carrot', 'mango']
print(shoplist)
#['apple', 'banana', 'carrot', 'mango']
#增加一項(xiàng)
shoplist.append('pear')
print(mylist)
#['apple', 'banana', 'carrot', 'mango', 'pear']
print(shoplist)
#['apple', 'banana', 'carrot', 'mango', 'pear']
print('Copy by making a full slice')
#那需要如何賦值才不會(huì)這樣呢？
mylist_slice = shoplist[:];
print(mylist_slice);
print(shoplist);
#['apple', 'banana', 'carrot', 'mango', 'pear']
print("del 第一個(gè)項(xiàng)目")
del mylist_slice[0];
print(mylist_slice);
#['banana', 'carrot', 'mango', 'pear']
print(shoplist);
#['apple', 'banana', 'carrot', 'mango', 'pear']
