python-字典学习

python-字典学习

元组是()
列表是[]
字典是{}

root@kali:~/python# python
Python 2.7.3 (default, Mar 14 2014, 11:57:14) 
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.

>>> product_dic = {'Car':260000,'Ipad':3500,'Coffee':35,'Close':199}#创建字典
>>> product_dic{'Car'}
  File "<stdin>", line 1
    product_dic{'Car'}
               ^
SyntaxError: invalid syntax
>>> product_dic['Car']#使用方括号[]定位元素
260000
>>> product_dic['Coffee']
35
>>> product_dic.keys()#定位所有元素
['Ipad', 'Car', 'Coffee', 'Close']
>>> product_dic.values()#定位所有元素的价格
[3500, 260000, 35, 199]
>>> product_dic.items()#打印所有元素及价格
[('Ipad', 3500), ('Car', 260000), ('Coffee', 35), ('Close', 199)]

>>> for p,price in product_dic.items():#索引/遍历字典中所有元素与价格
...     print p,price
... 
Ipad 3500
Car 260000
Coffee 35
Close 199
>>> 

>>> product_dic.pop()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: pop expected at least 1 arguments, got 0
>>> product_dic
{'Ipad': 3500, 'Car': 260000, 'Coffee': 35, 'Close': 199}
>>> product_dic.pop('Close')#删除制定键值
199
>>> product_dic
{'Ipad': 3500, 'Car': 260000, 'Coffee': 35}
>>> product_dic.popitem()#默认删除第一值
('Ipad', 3500)
>>> product_dic
{'Car': 260000, 'Coffee': 35}
>>> product_dic['Close']=299#增加字典元素
>>> product_dic
{'Car': 260000, 'Coffee': 35, 'Close': 299}
>>> 

>>> product_dic.has_key('Car')#查找字典是否存在元素
True
>>> 

>>> product_dic
{'Car': 260000, 'Coffee': 35, 'Close': 299}
>>> product_dic.clear()#删除字段内所有元素
>>> product_dic
{}
>>>