Pythonic｜the zen of python

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Euan 10月 11, 2019
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Pythonic|python骨灰级进阶之路

首先来一段python之禅

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren’t special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one– and preferably only one –obvious way to do it.
Although that way may not be obvious at first unless you’re Dutch.
Now is better than never.
Although never is often better than right now.
If the implementation is hard to explain, it’s a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea – let’s do more of those!

The Zen of Python, by Tim Peters

Beautiful is better than ugly.

Explicit is better than implicit.

Simple is better than complex.

Complex is better than complicated.

Flat is better than nested.

Sparse is better than dense.

Readability counts.

Special cases aren’t special enough to break the rules.

Although practicality beats purity.

Errors should never pass silently.

Unless explicitly silenced.

In the face of ambiguity, refuse the temptation to guess.

There should be one– and preferably only one –obvious way to do it.

Although that way may not be obvious at first unless you’re Dutch.

Now is better than never.

Although never is often better than right now.

If the implementation is hard to explain, it’s a bad idea.

If the implementation is easy to explain, it may be a good idea.

Namespaces are one honking great idea – let’s do more of those!

中文翻译：

优美胜于丑陋

明了胜于晦涩

简单胜于复杂

复杂胜于杂乱

扁平胜于嵌套

间隔胜于紧凑

可读性很重要

特例不足以特殊到违背这些原则

不要忽视错误，除非程序需要这样做

面对模棱两可，拒绝猜测

解决问题最直接的方法应该有一种，最好只有一种

可能这种方法一开始不够直接，因为你不是范罗苏姆

做也许好过不做，但不想就做还不如不做

如果方案难以描述明白，那么一定是个糟糕的方案

如果容易描述，那么可能是个好方案

命名空间是一种绝妙的理念，多加利用

exp1

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for element in list:
    simple_process(element)

exp2

交换a,b

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a,b = b,a

exp3

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for i, color in enumerate(colors):
    print(i)

exp4

字符串连接时，普通的方式可以用 + 操作

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print(', '.join(names))

exp5

直接赋值,默认浅拷贝传递对象的引用而已,原始列表改变，被赋值的b也会做相同的改变

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>>> b=alist
>>> print b
[1, 2, 3, ['a', 'b']]
>>> alist.append(5)
>>> print alist;print b
[1, 2, 3, ['a', 'b'], 5]
[1, 2, 3, ['a', 'b'], 5]

copy浅拷贝，没有拷贝子对象，所以原始数据改变，子对象会改变

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>>> import copy

>>> c=copy.copy(alist)
>>> print alist;print c
[1, 2, 3, ['a', 'b']]
[1, 2, 3, ['a', 'b']]
>>> alist.append(5)
>>> print alist;print c
[1, 2, 3, ['a', 'b'], 5]
[1, 2, 3, ['a', 'b']]

>>> alist[3]
['a', 'b']
>>> alist[3].append('cccc')
>>> print alist;print c
[1, 2, 3, ['a', 'b', 'cccc'], 5]
[1, 2, 3, ['a', 'b', 'cccc']] 里面的子对象被改变了

深拷贝，包含对象里面的自对象的拷贝，所以原始对象的改变不会造成深拷贝里任何子元素的改变

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>>> import copy

>>> d=copy.deepcopy(alist)
>>> print alist;print d
[1, 2, 3, ['a', 'b']]
[1, 2, 3, ['a', 'b']]始终没有改变
>>> alist.append(5)
>>> print alist;print d
[1, 2, 3, ['a', 'b'], 5]
[1, 2, 3, ['a', 'b']]始终没有改变
>>> alist[3]
['a', 'b']
>>> alist[3].append("ccccc")
>>> print alist;print d
[1, 2, 3, ['a', 'b', 'ccccc'], 5]
[1, 2, 3, ['a', 'b']]  始终没有改变

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