python之元组、字典、字符串

tuple1 = (1, 2, 3, 4, 5)
print(tuple1[0])
print(tuple1[1])
print(tuple1[2])
print(tuple1[3])
print(tuple1[4])
# print(tuple1[5])	# 下标超过范围（越界）
print(tuple1[-1])	# 获取最后一个元素
print(tuple1[-5])	# 倒数从-1开始
# print(tuple1[-6])	# 超出范围（越界）

1
2
3
4
5
5
1

tuple2 = (1, 2, 3, 4, [5, 6, 7])
# tuple2[0] = 100   # 元组的元素不能变
tuple2[-1][0] = 500  # 元组本身的元素不能变，但是元组里面时一个列表，列表里面的元素是可变的
print(tuple2)

(1, 2, 3, 4, [500, 6, 7])

tuple3 = (1, 2, 3)
del tuple3

tuple4 = (1, 2, 3)
tuple5 = (4, 5, 6)
tuple6 = tuple4+tuple5
print(tuple6)

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

tuple7 = (1, 2, 3)
print(tuple7*3)

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

tuple8 = (1, 2, 3)
print(1 in tuple8)
print(4 in tuple8)

True
False

元组名[开始下标：结束下标]
从开始下标开始截取，截取到结束下标之前

tuple9 = (1, 2, 3, 4, 5, 6, 7, 8, 9)
print(tuple9[3:7])

print(tuple9[:7])　　 # 从开始一直截取到下标为止之前
print(tuple9[3:]) 　　# 从下标处一直截取到末尾

(4, 5, 6, 7)
(1, 2, 3, 4, 5, 6, 7)
(4, 5, 6, 7, 8, 9)

tuple10 = ((1, 2, 3), (4, 5, 6), (7, 8, 9))
print(tuple10[1][1])

5

tuple11 = (1, 2, 3, 4, 5)
print(len(tuple11))		# len() 返回元组中元素的个数
print(max(tuple11))		# max()	返回元组中的最大值
print(min(tuple11))		# min()	返回元素中的最小值

5
5
1

listNumber = [1, 2, 3]
tuple12 = tuple(listNumber)
print(tuple12)

(1, 2, 3)

for i in (1, 2, 3, 4, 5):
	print(i)

1
2
3
4
5

1.字典中的key必须唯一
2.key必须是不可变的对象
3.字符串，整数等都是不可变的，可以作为key
4.list是可变的，不能作为key

获取：字典名[key]

print(dict_core["leo"]) # 这样就能访问到key所对应的value

result = dict_core.get("leo")
if result == None:
 	print("没有")
else:
 	print("有")

dict_core.pop("tom")
print(dict_core)