元组

tuple 元组

元组中的元素不能修改。

元组用 () 定义，元素之间用 , 分隔。

程序示例：

tuple1 = (1, 2.5, "hello")
print(tuple1)  # (1, 2.5, 'hello')
print(type(tuple1))  # <class 'tuple'>

只有一个元素时，元素后面要加一个逗号。

程序示例：

tuple1 = ('apple')
print(tuple1)  # apple
print(type(tuple1))  # <class 'str'>
tuple2 = ('apple',)
print(tuple2)  # ('apple',)
print(type(tuple2))  # <class 'tuple'>

程序示例：

# 空元组
tuple1 = ()
print(tuple1)  # ()
print(type(tuple1))  # <class 'tuple'>
tuple2 = tuple()
print(tuple2)  # ()
print(type(tuple2))  # <class 'tuple'>

程序示例：

# 类型转换 tuple()
list1 = [1, 2, 3, 4, 5, 6, 7, 8, 9]
tuple1 = tuple(list1)
print(tuple1)  # (1, 2, 3, 4, 5, 6, 7, 8, 9)
print(type(tuple1))  # <class 'tuple'>
tuple2 = tuple("hello")
print(tuple2)  # ('h', 'e', 'l', 'l', 'o')
print(type(tuple2))  # <class 'tuple'>
tuple3 = tuple(range(1, 5))
print(tuple3)  # (1, 2, 3, 4)
print(type(tuple3))  # <class 'tuple'>

程序示例：

tuple1 = ('h', 'e', 'l', 'l', 'o')
list1 = list(tuple1)
print(list1)  # ['h', 'e', 'l', 'l', 'o']
print(type(list1))  # <class 'list'>
str1 = str(tuple1)
print(str1)  # ('h', 'e', 'l', 'l', 'o')
print(type(str1))  # <class 'str'>
print(str1[2])  # h，元组整体转为字符串，( 是索引为 0，' 是索引为 1，h 是索引为 2

程序示例：

# 索引
tuple1 = ('h', 'e', 'l', 'l', 'o')
print(tuple1[1])  # e
print(tuple1[-1])  # o

程序示例：

# 切片
tuple1 = (1, 2, 3, 4)
print(tuple1[::-1])  # (4, 3, 2, 1)

程序示例：

tuple1 = (1, 2, 3, 4)
print(len(tuple1))  # 4
print(max(tuple1))  # 4
print(min(tuple1))  # 1

程序示例：

tuple1 = (1, 2, 3, 4)
print(tuple1)  # (1, 2, 3, 4)
del tuple1
# print(tuple1)  # NameError: name 'tuple1' is not defined. Did you mean: 'tuple'?

程序示例：

tuple1 = (1, 2, 3, 4)
tuple2 = ("a", "b", "c", "d")
tuple3 = tuple1 + tuple2
print(tuple3)  # (1, 2, 3, 4, 'a', 'b', 'c', 'd')
tuple4 = tuple1 * 3
print(tuple4)  # (1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4)
print("e" in tuple4)  # False
print("e" not in tuple1)  # True

程序示例：

tuple1 = (1, 2, 3, 4)
# tuple1[2] = 4  # TypeError: 'tuple' object does not support item assignment

程序示例：

tuple1 = (1, 2, 3, 4, 1, 2, 1)
print(tuple1.count(1))  # 3
print(tuple1.count(10))  # 0
tuple2 = ("hello", "world", "good", "morning")
print(tuple2.index("good"))  # 2
# print(tuple2.index("well"))  # ValueError: tuple.index(x): x not in tuple

程序示例：

# 遍历元组
tuple1 = ("hello", "world", "good", "morning")
for i in tuple1:
    print(i)

结果：

hello
world
good
morning

程序示例：

# 遍历元组
tuple1 = ("hello", "world", "good", "morning")
for index, value in enumerate(tuple1):
    print(index, value)

结果：

0 hello
1 world
2 good
3 morning

程序示例：

# 遍历元组
tuple1 = ("hello", "world", "good", "morning")
for i in range(len(tuple1)):
    print(i, tuple1[i])

结果：

0 hello
1 world
2 good
3 morning

元组定义时的 () 并不是必须的。

程序示例：

t1 = 1,
print(t1)
print(type(t1))

结果：

(1,)
<class 'tuple'>