目錄python
元組是不可變的列表,即元組的值不可更改,所以元組通常只用於只存不取的需求。也所以元組能夠被列表取代掉,因此元組相比較列表使用的不多。元組相比較列表的優勢爲:列表的值修改後,列表的結構將會發生改變,而元組只須要存儲,所以列表在某種程度上而言須要佔用更多的內存。可是目前工業上內存已經不是問題了,因此工業上元組通常不會使用。code
1.用途:多個裝備、多個愛好、多門課程,甚至是多個女友索引
2.定義:在()內能夠有多個任意類型的值,逗號分隔元素內存
# my_girl_friend = tuple(('jason','tank','sean')) my_girl_friend = ('jason', 'tank', 'sean') print(f"my_girl_friend: {my_girl_friend}")
my_girl_friend: ('jason', 'tank', 'sean')
name_str = ('egon') # ()只是普通包含的意思 name_tuple = ('egon',) print(f"type(name_str): {type(name_str)}") print(f"type(name_tuple): {type(name_tuple)}")
type(name_str): <class 'str'> type(name_tuple): <class 'tuple'>
3.經常使用操做+內置方法:經常使用操做和內置方法:it
索引取值class
切片(顧頭不顧尾,步長)循環
長度len數據類型
成員運算in和not in方法
循環數據
count
index
1.索引取值
# tuple之索引取值 name_tuple = ('nick', 'jason', 'tank', 'sean') # name_tuple[0] = 'nick handsom' # 報錯 print(f"name_tuple[0]: {name_tuple[0]}")
name_tuple[0]: nick
2.切片(顧頭不顧尾,步長)
# tuple之切片 name_tuple = ('nick', 'jason', 'tank', 'sean') print(f"name_tuple[1:3:2]: {name_tuple[1:3:2]}")
name_tuple[1:3:2]: ('jason',)
3.長度
# tuple之長度 name_tuple = ('nick', 'jason', 'tank', 'sean') print(f"len(name_tuple): {len(name_tuple)}")
len(name_tuple): 4
4.成員運算
# tuple之成員運算 name_tuple = ('nick', 'jason', 'tank', 'sean') print(f"'nick' in name_tuple: {'nick' in name_tuple}")
'nick' in name_tuple: True
5.循環
# tuple之循環 name_tuple = ('nick', 'jason', 'tank', 'sean') for name in name_tuple: print(name)
nick jason tank sean
6.count()
# tuple之count() name_tuple = ('nick', 'jason', 'tank', 'sean') print(f"name_tuple.count('nick'): {name_tuple.count('nick')}")
name_tuple.count('nick'): 1
7.index()
# tuple之index() name_tuple = ('nick', 'jason', 'tank', 'sean') print(f"name_tuple.index('nick'): {name_tuple.index('nick')}")
name_tuple.index('nick'): 0
4.存一個值or多個值:多個值
5.有序or無序:有序
name_tuple = ('nick',) print(f'first:{id(name_tuple)}')
first:4394454152
6.可變or不可變:不可變數據類型
l = ['a', 'b', 'c'] print(f"id(l[0]): {id(l[0])}") l[0] = 'A' print(f"id(l[0]): {id(l[0])}")
id(l[0]): 4357367208 id(l[0]): 4357775176
列表可變的緣由是:索引所對應的值的內存地址是能夠改變的
元組不可變得緣由是:索引所對應的值的內存地址是不能夠改變的,或者反過來講,只要索引對應值的內存地址沒有改變,那麼元組是始終沒有改變的。
t1 = (['a', 'b', 'c'], 'wc', 'office') print(f"id(t1[0]): {id(t1[0])}") print(f"id(t1[1]): {id(t1[1])}") print(f"id(t1[2]): {id(t1[2])}") t1[0][0] = 'A' print(f"t1[0][0]: {t1[0][0]}") print(f"id(t1[0]): {id(t1[0])}") print(f"t1: {t1}")
id(t1[0]): 4394709960 id(t1[1]): 4374626968 id(t1[2]): 4394453568 t1[0][0]: A id(t1[0]): 4394709960 t1: (['A', 'b', 'c'], 'wc', 'office')