python(13)--字典（Dict）
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一、字典的基本操作
1.定义字典
字典也是一个列表型的数据结构，字典的数据是用“ ”装的（列表：[ ]，元组：( )），字典的元素是一一对应的关系“key-value”。
格式：
Dictname= key1:value1,...,key2:value2
#value是任何的python的对象
#字典的元素数量也是用len()函数
多说无益，直接看例子比较清晰：
实例：
flower=rose:10,orchid:16,carnation:8
tea=红茶:30,绿茶:20,茉莉花茶:40
print(flower)
print(tea)
print("字典flower的元素数量是：",len(flower))
print("字典的数据类型：",type(tea))
编辑
2.建立空字典
实例：
print("``````````````````````````````````````````````````````````")
flower=
flower[rose]=13
flower[orchid]=16
print(flower)
print("``````````````````````````````````````````````````````````")
编辑
3.列出字典元素的值
格式：
flower【rose】
#注意列出字典元素的值要用中括号哦“[ ]”
#上面语句表达的意思是字典 flower 的 rose（key）的对应 10（value）值。
实例：
print("``````````````````````````````````````````````````````````")
flower=rose:10,orchid:16,carnation:8
tea=红茶:30,绿茶:20,茉莉花茶:40
print("一支玫瑰的价钱是：",flower[rose])
print("红茶一袋的价钱是：",tea[红茶])
print("``````````````````````````````````````````````````````````")
编辑
如果有两个“rose”，两个“红茶”呢，元素对应的值（value）是哪个呢？
print("``````````````````````````````````````````````````````````")
flower=rose:10,orchid:16,carnation:8,rose:15
tea=红茶:30,绿茶:20,茉莉花茶:40,红茶:13
print("一支玫瑰的价钱是：",flower[rose])
print("红茶一袋的价钱是：",tea[红茶])
print("``````````````````````````````````````````````````````````")
编辑
如上所示，字典中的元素对应值被后面的值占领了。
4.增加字典元素
实例：
print("``````````````````````````````````````````````````````````")
flower=rose:10,orchid:16,carnation:8
tea=红茶:30,绿茶:20,茉莉花茶:40
flower[tuilp]=13
print(flower)
print("``````````````````````````````````````````````````````````")
5.更改元素内容
实例：
print("``````````````````````````````````````````````````````````")
flower=rose:10,orchid:16,carnation:8
tea=红茶:30,绿茶:20,茉莉花茶:40
flower[rose]=13
print(flower)
print("``````````````````````````````````````````````````````````")
编辑
6.删除字典（特定元素）
删除元素实例：
print("``````````````````````````````````````````````````````````")
flower=rose:10,orchid:16,carnation:8
tea=红茶:30,绿茶:20,茉莉花茶:40
del flower[rose]
print(flower)
print("``````````````````````````````````````````````````````````")
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删除字典实例：
print("``````````````````````````````````````````````````````````")
flower=rose:10,orchid:16,carnation:8
del flower
print(flower)
print("``````````````````````````````````````````````````````````")
7. 字典的复制
print("``````````````````````````````````````````````````````````")
flower=rose:10,orchid:16,carnation:8
copyflower=flower.copy()
print(flower)
print(copyflower)
print("``````````````````````````````````````````````````````````")
二、遍历字典
1.遍历字典的key-value
flower=rose:10,
orchid:16,
carnation:8
for flowers,price in flower.items():
print("花名：",flowers)
print("价格：",price)
print("\\n")
编辑
2.遍历字典的键(key)
flower=rose:10,
orchid:16,
carnation:8
for flowers in flower.keys():
print("花名：",flowers)
print("\\n")
编辑
没有keys()函数也行：
flower=rose:10,
orchid:16,
carnation:8
for flowers in flower:
print("花名：",flowers)
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3.遍历字典的值（value）
flower=rose:10,
orchid:16,
carnation:8
for flowers in flower.values():
print("价格：",flowers)
编辑
4.字典里面放字典
实例：人物介绍
role=
鲁班:
技能:土木建筑,
职业:工匠
,
钟无艳:
技能:出谋划策,
职业:中国古代四大丑女之一
,
蔡文姬:
技能:琴棋书画,
职业:董祀之妻
for a,b in role.items():
print("姓名：",a)
print("介绍：",b)
三、简单介绍下函数
len()：求元素个数
get()：搜寻字典的key
格式：返回值=字典名.get(key)
pop()：删除元素
格式：返回值=字典名.pop(key)
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