97 lines
2.4 KiB
Markdown
97 lines
2.4 KiB
Markdown
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# Python //运算符–Python 中的楼层划分
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> 原文：<https://www.askpython.com/python/python-floor-division-double-slash-operator>
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Python //运算符也叫地板除法运算符。它是 Python 中的算术运算符之一。它适用于 Python 中的数字。
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## Python //运算符
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它类似于除法运算符，只是它返回除法运算的整数部分。所以，如果除法的输出是 3.999，这将返回 3。所以才叫楼分算子。
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我们来看一些 Python 中的楼层划分的例子。
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### 1.整数的地板除法
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```py
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>>> 10//3
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3
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>>> 10//2
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5
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```
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### 2.用彩车分隔地板
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```py
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>>> 10.0//3
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3.0
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>>> 10//2.0
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5.0
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>>> 11.99//3.00
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3.0
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```
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### 3.复数的楼层划分
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复数不支持地板除法。如果我们尝试对复数使用//运算符，它将抛出 *TypeError:不能对复数取整。*
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```py
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>>> x = 10 + 3j
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>>> type(x)
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<class 'complex'>
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>>> x // 3
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Traceback (most recent call last):
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File "<stdin>", line 1, in <module>
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TypeError: can't take floor of complex number.
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>>>
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```
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## 重载//运算符
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我们知道 Python 支持运算符重载。如果要支持对象的//操作符，需要重写 __floordiv__(self，other)方法。让我们看一个重载地板除法运算符的简单例子。
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```py
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# Floor Division Operator overloading example
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class Data:
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id = 0
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def __init__(self, i):
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self.id = i
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def __floordiv__(self, other):
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print("overloading // operator")
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return self.id // other.id
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d1 = Data(10)
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d2 = Data(3)
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print(d1 // d2)
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```
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输出:
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## 摘要
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* Python //运算符处理数字–int 和 float。
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* 基数除法运算符返回除法运算的整数部分。
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* 如果被除数和除数都是整数，则地板除法也将返回 int。
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* 如果被除数和除数中有一个是 float，则 floor 除法将返回一个 float。
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* 我们不能对复数使用//运算符。
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## 下一步是什么？
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* [Python 中的运算符](https://www.askpython.com/python/python-operators)
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* [Python 中的数字](https://www.askpython.com/python/python-numbers)
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* [Python 中的函数](https://www.askpython.com/python/python-functions)
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* [Python for 循环](https://www.askpython.com/python/python-for-loop)
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* [Python 列表](https://www.askpython.com/python/list/python-list)
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## 参考
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* [Python 文档](https://python-reference.readthedocs.io/en/latest/docs/operators/floor_division.html)
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