[Python知识库]Python：元组与字典操作

1.元组：tup

1.1当元组中只有一个元素时，需要加“ , ”? ? 否则为字符串类型?

tup1 = ("Tom")
print(type(tup1))

tup2 = ("Tom",)
print(type(tup2))

1.2元组中的索引和切片操作[起始位，结束位，步数]

tup = ("Tom", 20, 180, 60)
print(tup[0])
print(tup[-3])
print(tup[::-2])       # 负数表示倒着输出,2表示隔一个输出

1.3获取长度函数：len( )?

tup = ("Tom", 20, 180, 60)
s = "123456wsl"
print(len(tup))
print(len(s))

1.4元组中添加元素:tup1+tup2

tup = ("Tom", 20, 180, 60)
tup2 = ("man",)
print(tup+tup2)
tup3 = tup+tup2
print(tup3)

2.字典：dict

2.1通过键（key）获取值（value）

D = {"name": "Alex", "Age": "18", "gander": "man"}
print(D["name"])

# dict.get(key,默认值)通过key获取值，如果不存在，返回默认值
print(D.get(name))

2.2添加键值对

D = {"name": "Alex", "Age": "18", "gander": "man"}

# 添加键值对
D["height"] = 180
print(D)

# 添加多个键值对
D.update([[1, "A"], ["weight", "60"]])
print(D)

2.3修改键值对

D1 = {"name": "Alex", "Age": "18", "gander": "man"}
D1["name"] = "Tony"
print(D1)

2.4清空全部键值对

D1 = {"name": "Alex", "Age": "18", "gander": "man"}
D1.clear()
print(D1)

2.5拿出字典中的全部键、值、键值对

D = {"name": "Alex", "Age": "18", "gander": "man"}

print(D.keys())
print(D.values())
print(D.items())

2.6快速生成一个字典: {}.formkeys()?

# {}.formkeys()方法生成的字典为一对多！！！

D2 = ['name','age','height']
D3 = ["Alex", "18",  "182"]
print({}.fromkeys(D2, D3))