Python中元组相关知识

# 创建空元祖
t = ()
print(type(t))

# 创建只有一个值的元组
# 观察可知元组中如果纯数字的话，类型是int，加个逗号就好了
t1 = (1)
t2 = (1,)
print(type(t1))
print(type(t2))

t = 1,# 也要有逗号
print(type(t))
print(t)

# 创建多个值的元组类型1
t = (1,2,3,4,5)
print(type(t))
print(t)
# 创建多个值的元组类型2
t =  1,2,3,4,5
print(type(t))
print(t)

# 使用其他结构创建
l = [1,2,3,4,5]
t = tuple(l)
print(type(t))
print(t)

<class 'tuple'>
<class 'int'>
<class 'tuple'>
<class 'tuple'>
(1,)
<class 'tuple'>
(1, 2, 3, 4, 5)
<class 'tuple'>
(1, 2, 3, 4, 5)
<class 'tuple'>
(1, 2, 3, 4, 5)

元组的特性

# 索引操作
t = (1,2,3,45)
print(t[2])

3

# 超标在list中超标是会报错的，而tuple中不会报错
#list中
print(t[12])

报错：

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
<ipython-input-97-81e870641898> in <module>()
      1 # 超标在list中超标是会报错的，而tuple中不会报错
----> 2 print(t[12])

IndexError: tuple index out of range

t = (1,2,3,4,5,6)
t1 = t[1::2]
print(id(t))
print(id(t1))
print(t1)

# tuple中的切片是不报错的
print(t[1:200])

140106142035688
140106141748032
(2, 4, 6)
(2, 3, 4, 5, 6)

# 序列相加
t1 = (1,2,3)
t2 = (4,5,6)
# 传址操作
print(t1)
print(id(t1))
t1 = t1 + t2
print(t1)
print(id(t1))

# 以上操作，类似于
t1 = (1,2,3)
t1 = (2,3,4)

# tuple 的不可修改，指的是内容的不可修改
# 修改tuple内容会导致报错
t1[1] = 100

(1, 2, 3)
140106142173296
(1, 2, 3, 4, 5, 6)
140106142035688

# 元组相乘
t = (1,2,3)
t = t*3
print(t)

(1, 2, 3, 1, 2, 3, 1, 2, 3)

# 成员检测
t = (1,2,3)
if 2 in t:
    print("yes")
else:
    print("no")

yes

# 元组遍历，一般采用for循环
# 1.单层元组遍历
t = (1,2,3,"python","java")
for i in t:
    print(i,end=" ")

1 2 3 python java 

# 2.双层元组遍历
t = ((1,2,3),("python","java","c"))
#比对以上元组的遍历，可以如下
#1.
for i in t:
    print(i,end=" ")

print()
for k,m,n in t:
    print(k,"--",m,"--",n)

(1, 2, 3) ('python', 'java', 'c') 
1 -- 2 -- 3
python -- java -- c

关于元组的函数：

# len：获取元组的长度
t = (1,2,3,4,5)
len(t)
print(len(t))

# tuple:转换或创建元组
l = [1,2,3,14,5,60]
t = tuple(l)
print(t)

t = tuple()
print(t)

(1, 2, 3, 14, 5, 60)
()

# count： 计算指定数据出现的次数
t = (1,2,1,2,6,5,1)
print(t.count(1))

3

# index ：求制定元素在元组中的索引位置

print(t.index(6))
#如果需要查找的数字是多个，则返回第一个

print(t.index(1))

4
0
元组变量交换法

# 俩个变量交换值
a = 1
b = 3
print(a)
print(b)
print("*"*30)
# Java程序员会这么写
c = a
a = b
b = c
print(a)
print(b)
print("*"*30)

# python程序员的写法
a,b=b,a
print(a)
print(b)

1
3
******************************
3
1
******************************
1
3