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170 lines
1.0 KiB
Markdown
170 lines
1.0 KiB
Markdown
# 什么是对象？
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在 `Python` 中，几乎所有的东西都是对象。
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整数是对象：
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In [1]:
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```py
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a = 257
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```
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In [2]:
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```py
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type(a)
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```
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Out[2]:
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```py
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int
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```
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In [3]:
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```py
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id(a)
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```
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Out[3]:
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```py
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53187032L
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```
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`b` 和 `a` 是同一个对象：
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In [4]:
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```py
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b = a
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```
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In [5]:
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```py
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id(b)
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```
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Out[5]:
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```py
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53187032L
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```
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In [6]:
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```py
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c = 258
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id(c)
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```
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Out[6]:
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```py
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53186960L
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```
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函数：
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In [7]:
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```py
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def foo():
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print 'hi'
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```
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In [8]:
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```py
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type(foo)
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```
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Out[8]:
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```py
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function
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```
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In [9]:
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```py
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id(foo)
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```
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Out[9]:
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```py
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63632664L
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```
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`type` 函数本身也是对象：
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In [10]:
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```py
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type(type)
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```
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Out[10]:
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```py
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type
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```
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In [11]:
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```py
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id(type)
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```
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Out[11]:
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```py
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506070640L
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```
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只有一些保留的关键词不是对象：
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In [12]:
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```py
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id(if)
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```
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```py
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File "<ipython-input-12-1e0d1307109a>", line 1
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id(if)
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^
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SyntaxError: invalid syntax
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```
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In [13]:
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```py
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id(+)
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```
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```py
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File "<ipython-input-13-86853fe3c6fd>", line 1
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id(+)
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^
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SyntaxError: invalid syntax
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``` |