Python字典的创建
方法一：
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>>> blank_dict = {}>>> product_dict = {'MAC':8000,'Iphone':5000, 'ipad':4000, 'mp3': 300}>>> product_dict{'ipad': 4000, 'MAC': 8000, 'Iphone': 5000, 'mp3': 300}>>> blank_dict,product_dict({}, {'ipad': 4000, 'MAC': 8000, 'Iphone': 5000, 'mp3': 300}) |
方法二：
从Python 2.2版本开始
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>>> fdict = dict((['www','www.linuxeye.com'],['blog','blog.linuxeye.com']))>>> fdict{'blog': 'blog.linuxeye.com', 'www': 'www.linuxeye.com'} |
方法三：
从Python 2.3版本开始, 可以用一个很方便的内建方法fromkeys() 来创建一个”默认”字典, 字典中元素具有相同的值 (如果没有给出， 默认为None):
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>>> fk_dict = {}.fromkeys(('a','b'),'LinuxEye')>>> fk_dict{'a': 'LinuxEye', 'b': 'LinuxEye'}>>> fk2_dict = {}.fromkeys(('yeho','python'))>>> fk2_dict{'python': None, 'yeho': None}>>> fk3_dict = {}.fromkeys('yeho','python')>>> fk3_dict{'y': 'python', 'h': 'python', 'e': 'python', 'o': 'python'} |
Python字典查、增、删、改
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>>> product_dict = {'MAC':8000,'Iphone':5000, 'mp3': 300}>>> product_dict['Iphone']5000>>> product_dict['ipad'] = 4000 #增>>> product_dict{'ipad': 4000, 'MAC': 8000, 'Iphone': 5000, 'mp3': 300} >>> product_dict.keys() #查看索引['ipad', 'MAC', 'Iphone', 'mp3']>>> product_dict.values() #查看值[4000, 8000, 5000, 300]>>> product_dict.items()[('ipad', 4000), ('MAC', 8000), ('Iphone', 5000), ('mp3', 300)]>>> for product,price in product_dict.items():... print product,price...ipad 4000MAC 8000Iphone 5000mp3 300>>> product_dict.has_key('Iphone') #判断key是否存在True>>> product_dict.has_key('Itouch')False >>> product_dict.pop('MAC') #删除指定key和value 8000 >>> product_dict {'ipad': 4000, 'Iphone': 5000, 'mp3': 300} >>> product_dict.popitem() #删除第一个key和value ('ipad', 4000) >>> product_dict {'Iphone': 5000, 'mp3': 300} >>> product_dict = {'Iphone': 5000, 'mp3': 300} >>> del product_dict['Iphone'] #用del函数删除指定key和value >>> product_dict {'mp3': 300} >>> product_dict['mp3'] = 299 #改 >>> product_dict {'mp3': 299} >>> product_dict.clear() #清空字典内容（空字典） >>> product_dict {} >>> del product_dict #删除字典 >>> product_dict = {'mp3': 300} >>> del product_dict #已删除报错 Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name 'product_dict' is not defined |
