【Python】字典的使用及相关函数

字典是另一种可变容器模型，且可存储任意类型对象

向空字段添加数据

d = {}

d["name"] = "zhangsan"
print(d)

》》》运行结果
{'name': 'zhangsan'}

进程已结束，退出代码为 0

 

 

将列表数据写入字段中

　　1、部分数值

d ={}
a = ['a','b','c','d','e']
b = ['11','22','33','44','55']

for i in range(3):
    d[a[i]] = b[i]
print(d)

{'a': '11', 'b': '22', 'c': '33'}

进程已结束，退出代码为 0

 

　　2、部分数值

d ={}
a = ['1','2','3','4','5']
b = ['11','22','33','44','55']

for i in range(2,4]:
    d[a[i]] = b[i]
print(d)

 

{'3': '33', '4': '44'}

进程已结束，退出代码为 0

 

 

　　3、 全部数值

d ={}
a = ['1','2','3','4','5']
b = ['11','22','33','44','55']

for i in range(len(a)):
    d[a[i]] = b[i]
print(d)

{'1': '11', '2': '22', '3': '33', '4': '44', '5': '55'}

进程已结束，退出代码为 0

 

读取字典值

d = {}

d["name"] = "zhangsan"
d["age"] = "18"
print(d)
print(d["name"])

 

{'name': 'zhangsan', 'age': '18'}
zhangsan

进程已结束，退出代码为 0

 

 

修改字典值

d = {}

d["name"] = "zhangsan"
d["age"] = "18"
print(d)
print(d["name"])
d["name"] = "zhangsan2"
print(d)

{'name': 'zhangsan', 'age': '18'}
zhangsan
{'name': 'zhangsan2', 'age': '18'}

进程已结束，退出代码为 0

 

 

删除字典

d = {}

d["name"] = "zhangsan"
d["age"] = "18"
print(d)
print(d["name"])
d["name"] = "zhangsan2"
print("修改 key value",d)
del d["age"]
print("删除key-age",d)
d.clear()
print("清空字典",d)

{'name': 'zhangsan', 'age': '18'}
zhangsan
修改 key value {'name': 'zhangsan2', 'age': '18'}
删除key-age {'name': 'zhangsan2'}
清空字典 {}

进程已结束，退出代码为 0

 

# del d 删除字典，字典将会不存在，输出d 时提示异常

 

dict.items()

　　以列表返回可遍历的(键, 值) 元组数组。

d ={}
a = ['a','b','c','d','e']
b = ['11','22','33','44','55']

for i in range(len(a)):
    d[a[i]] = b[i]
print(d)

print(d.items())

for key,value in d.items():
    print(key,value)

di = {key:value for key,value in d.items() if key in a}
print(di)

de = [{key:value for key,value in d.items() if key in b}]
print(de)

{'a': '11', 'b': '22', 'c': '33', 'd': '44', 'e': '55'}
dict_items([('a', '11'), ('b', '22'), ('c', '33'), ('d', '44'), ('e', '55')])
a 11
b 22
c 33
d 44
e 55
{'a': '11', 'b': '22', 'c': '33', 'd': '44', 'e': '55'}
[{}]

进程已结束，退出代码为 0