字典包含在花括号中。因此，如果要定义一个字典，只需要把一个字典设置为一对空的花括号 ``` states = {} print type(states) states = {"Virginia":"Richmond","Maryland":"Annapolis","New York":"Albany"} print states ``` 修改字典 - 添加字典内容 ``` states = {"Vriginia":"Richmond"} states['Oregon'] = "Salem" print states ``` - 修改字典内容 ``` user_mail = {'12306':'12306.com'} user_mail['12306'] = 'qq.com' print user_mail ``` - 删除字典内容 ``` arr = {"1":"a","2":"b","3":"c"} arr.pop("2") print arr ```