1、内置数据类型
使用变量存储数据时，为了更充分利用内存空间，我们可以为变量指定不同的数据类型。并且不同类型可以执行不同的操作。Python默认具有以下内置数据类型：
字符串类型：str
数值类型： int，float， complex
序列类型： list，tuple， range
映射类型： dict
集合类型： set， frozenset
布尔值类型： bool
二进制类型： bytes，bytearray， memoryview
2、使用type()获取变量的数据类型
可以使用以下type()函数获取任何对象的数据类型：
例子，
打印输出变量x的数据类型：
x = 5
print(type(x))
以下是Python中所有内置数据类型：
例如：
print(type("Hello"))print(type(3))print(type(3.14))print(type(1j))print(type(["c", "java", "python"]))print(type(("c", "java", "python")))
print(type(range(6)))print(type({"name" : "python", "age" : 12}))print(type({"c", "java", "python"}))
print(type(frozenset({"c", "java", "python"})))
print(type(True))print(type(b"Hello"))print(type(bytearray(5)))print(type(memoryview(bytes(5))))3、指定变量数据类型
在Python中，当将值分配给变量时，将设置数据类型：
示例 | 数据类型 |
x = "Hello World" | str |
x = 20 | int |
x = 20.5 | float |
x = 1j | complex |
x = ["c", "python", "java"] | list |
x = ("c", "python", "java") | tuple |
x = range(6) | range |
x = {"name" : "python", "age" : 20} | dict |
x = {"c", "python", "java"} | set |
x = frozenset({"c", "python", "java"}) | frozenset |
x = True | bool |
x = b"Hello" | bytes |
x = bytearray(5) | bytearray |
x = memoryview(bytes(5)) | memoryview |
4、通过构造函数指定数据类型
如果要指定数据类型，则可以使用以下构造函数：
示例 | 数据类型 |
x = str("Hello World") | str |
x = int(20) | int |
x = float(20.5) | float |
x = complex(1j) | complex |
x = list(("c", "python", "java")) | list |
x = tuple(("c", "python", "java")) | tuple |
x = range(6) | range |
x = dict(name="wonhero", age=3) | dict |
x = set(("c", "java", "python")) | set |
x = frozenset(("c", "python", "java")) | frozenset |
x = bool(5) | bool |
x = bytes(5) | bytes |
x = bytearray(5) | bytearray |
x = memoryview(bytes(5)) | memoryview |
5、Python常用数据类型示例
shoplist = ['apple', 'mango', 'carrot', 'banana']print('I have ', len(shoplist), ' items to purchase.')print('These items are: ', end = '')for item in shoplist: print(item, end = ' ')print('\nI also have to buy rice.')shoplist.append('rice')print('My shopping list is now ', shoplist)print('I will sort my list now')shoplist.sort()print('Sorted shopping list is ', shoplist)print('The first item I will buy is ', shoplist[0])olditem = shoplist[0]del shoplist[0]print('I bought the ', olditem)print('My shopping list is now ', shoplist)zoo = ('python', 'elephant', 'penguin')print('Number of animals in the zoo is ', len(zoo))new_zoo = 'monkey', 'camel', zooprint('Number of cages in the new zoo is ', len(new_zoo))print('All animals in new zoo are ',new_zoo)print('Animals brought from old zoo are', new_zoo[2])print('Last animal brought from old zoo is ', new_zoo[2][2])print('Number of animals in the new zoo is ', len(new_zoo) - 1 + len(new_zoo[2]))ab = { 'Swaroop' : 'Swaroop@Swaroopch.com', 'Larry' : 'larry@wall.org', 'Matsumoto' : 'matz@ruby-lang.org', 'Spammer' : 'spammer@hotmail.com'}print("Swaroop's address is ", ab['Swaroop'])del ab['Spammer']print('\nThere are {0} contacts in the address-book\n'.format(len(ab)))for name, address in ab.items(): print('Contatc {0} at {1}'.format(name, address))ab['Guido'] = 'guido@python.org'if 'Guido' in ab: print("\nGuido's address is ", ab['Guido'])name = 'Swaroop'print('Item 0 is ', shoplist[0])print('Item 1 is ', shoplist[1])print('Item 2 is ', shoplist[2])print('Item 3 is ', shoplist[3])print('Item -1 is ', shoplist[-1])print('Item -2 is ', shoplist[-2])print('Character 0 is ', name[0])print('Item 1 to 3 is ',shoplist[1:3])print('Item 2 to end is ',shoplist[2:])print('Item 1 to -1 is ',shoplist[1:-1])print('Item start to end is ',shoplist[:])print('Character 1 to 3 is ', name[1:3])print('Character 2 to end is ', name[2:])print('Character 1 to -1 is ', name[1:-1])print('Character start to end is ', name[:])bri = set(['brazil', 'russia', 'India', 'China'])print('India' in bri)