python tuple 元组

python tuple 元组
元组：不可变，无序 tuple
1，定义：a,一维元组/b,二维元组/c,三维元组
2，访问:a,正/b,反
3，切片:a,正切/b,反切/c,混合切
4，遍历:a,一维遍历/b,二维遍历

1，定义
a,一维元组

userinfo1=(1,"zhangsan",18,"sales")
print(userinfo1)

(1, ‘zhangsan’, 18, ‘sales’)
b,二维元组

userinfo1=((1,"zhangsan",18,"sales"),(2,"wangwu",20,"it"))
print(userinfo1)

((1, ‘zhangsan’, 18, ‘sales’), (2, ‘wangwu’, 20, ‘it’))
c,三维元组

userinfo1=((1,"zhangsan",18,"sales"),(2,"wangwu",20,"it",(3,"zhaoliu",16,"student")))
print(userinfo1)

((1, ‘zhangsan’, 18, ‘sales’), (2, ‘wangwu’, 20, ‘it’, (3, ‘zhaoliu’, 16, ‘student’)))
2，访问
a,正（从做到右，从0开始，0,1,2,3…）

userinfo1=(1,"zhangsan",18,"sales")
print(userinfo1)
print(userinfo1[0])
print(userinfo1[3])

(1, ‘zhangsan’, 18, ‘sales’)
1
sales
b,反（从右到左，从-1开始,-1,-2,-3…）

userinfo1=(1,"zhangsan",18,"sales")
print(userinfo1)
print(userinfo1[-1])
print(userinfo1[-4])

(1, ‘zhangsan’, 18, ‘sales’)
sales
1
3，切片(按照索引进行获取，
格式：tuple[start:end]
#从左往右进行，以start开始，end结束，但是不包含end，#start要大于end,是看实际位置，如果start实际位置在end位置的右边，则切出来的为空，)
#start省略则从0开始
#end省略，则直接切到最后
a,正切

userinfo1=(1,"zhangsan",18,"sales")
print(userinfo1[1:3])

( ‘zhangsan’, 18)
#省略start，直接从0开始

userinfo1=(1,"zhangsan",18,"sales")
print(userinfo1[:3])

(1, ‘zhangsan’, 18)
#省略end,直接切到最后

userinfo1=(1,"zhangsan",18,"sales")
print(userinfo1[1:])

(‘zhangsan’, 18, ‘sales’)
b,反切

userinfo1=(1,"zhangsan",18,"sales")
print(userinfo1[-3:-1])

(‘zhangsan’, 18)
#省略start，直接从0开始

userinfo1=(1,"zhangsan",18,"sales")
print(userinfo1[:-1])

(1, ‘zhangsan’, 18)
#省略end，切到最后

userinfo1=(1,"zhangsan",18,"sales")
print(userinfo1[-3:])

(‘zhangsan’, 18, ‘sales’)
c,混合切，遵循实际位置的原则，一般应该很少用

userinfo1=(1,"zhangsan",18,"sales")
print(userinfo1[-3:2])

(‘zhangsan’,)
4，遍历
a,一维遍历

userinfo1=(1,"zhangsan",18,"sales")
for i in range(len(userinfo1)):
    print(userinfo1[i])

1
zhangsan
18
sales

b,二维遍历

userinfo1=((1,"zhangsan",18,"sales"),(2,"wangwu",20,"it"))
print(userinfo1[0])
print(userinfo1[1])
for i in range(len(userinfo1)):
    for j in range(len(userinfo1[i])):
        print(userinfo1[i][j])

(1, ‘zhangsan’, 18, ‘sales’)
(2, ‘wangwu’, 20, ‘it’)
1
zhangsan
18
sales
2
wangwu
20
it