Pylint 是一个 Python 代码分析工具，它分析 Python 代码中的错误，查找不符合代码风格标准（Pylint 默认使用的代码风格是 PEP 8）和有潜在问题的代码。
* Pylint 是一个 Python 工具，除了平常代码分析工具的作用之外，它提供了更多的功能：如检查一行代码的长度，变量名是否符合命名标准，一个声明过的接口是否被真正实现等。
* Pylint 的一个很大的好处是它的高可配置性，高可定制性，并且可以很容易写小插件来添加功能。
* 如果运行两次 Pylint，它会同时显示出当前和上次的运行结果，从而可以看出代码质量是否得到了改进。
演示代码：
2 # _*_ conding:utf-8 _*_
3
4 import datetime
5
6 class MyFile:
7 def __init__ (self, file_full_name):
8 self. __file_full_name = file_full_name
9
10 def append(self, value):
11 f = open(self. __file_full_name , ' a ' )
12 f.write(value)
13 f.close()
14
15 def content(self):
16 f = open(self. __file_full_name , ' r ' )
17 return f.read()
18
19
20 if __name__ == " __main__ " :
21 f = MyFile( ' test.txt ' )
22 f.append( " abeen.... " + str(datetime.datetime.now()) + " \n " )
23 print f.content()
代码分析结果：
abeen@localhost:~/learn_test/file$ pylint file_test.py
************* Module file_test
C: 1: Missing docstring
C: 6:MyFile: Missing docstring
W: 11:MyFile.append: Redefining name 'f' from outer scope (line 21)
C: 10:MyFile.append: Missing docstring
C: 11:MyFile.append: Invalid name "f" (should match [a-z_][a-z0-9_]{2,30}$)
W: 16:MyFile.content: Redefining name 'f' from outer scope (line 21)
C: 15:MyFile.content: Missing docstring
C: 16:MyFile.content: Invalid name "f" (should match [a-z_][a-z0-9_]{2,30}$)
C: 21: Invalid name "f" (should match (([A-Z_][A-Z0-9_]*)|(__.*__))$)
Report
======
15 statements analysed.
Raw metrics
-----------
+----------+-------+------+---------+-----------+
|type |number |% |previous |difference |
+==========+=======+======+=========+===========+
|code |16 |80.00 |16 |= |
+----------+-------+------+---------+-----------+
|docstring |0 |0.00 |0 |= |
+----------+-------+------+---------+-----------+
|comment |2 |10.00 |2 |= |
+----------+-------+------+---------+-----------+
|empty |2 |10.00 |2 |= |
+----------+-------+------+---------+-----------+
Duplication
-----------
+-------------------------+------+---------+-----------+
| |now |previous |difference |
+=========================+======+=========+===========+
|nb duplicated lines |0 |0 |= |
+-------------------------+------+---------+-----------+
|percent duplicated lines |0.000 |0.000 |= |
+-------------------------+------+---------+-----------+
Statistics by type
------------------
+---------+-------+-----------+-----------+------------+---------+
|type |number |old number |difference |%documented |%badname |
+=========+=======+===========+===========+============+=========+
|module |1 |1 |= |0.00 |0.00 |
+---------+-------+-----------+-----------+------------+---------+
|class |1 |1 |= |0.00 |0.00 |
+---------+-------+-----------+-----------+------------+---------+
|method |3 |3 |= |33.33 |0.00 |
+---------+-------+-----------+-----------+------------+---------+
|function |0 |0 |= |0.00 |0.00 |
+---------+-------+-----------+-----------+------------+---------+
Messages by category
--------------------
+-----------+-------+---------+-----------+
|type |number |previous |difference |
+===========+=======+=========+===========+
|convention |7 |7 |= |
+-----------+-------+---------+-----------+
|refactor |0 |0 |= |
+-----------+-------+---------+-----------+
|warning |2 |2 |= |
+-----------+-------+---------+-----------+
|error |0 |0 |= |
+-----------+-------+---------+-----------+
Messages
--------
+-----------+------------+
|message id |occurrences |
+===========+============+
|C0111 |4 |
+-----------+------------+
|C0103 |3 |
+-----------+------------+
|W0621 |2 |
+-----------+------------+
Global evaluation
-----------------
Your code has been rated at 4.00/10 (previous run: 4.00/10)
修改后代码：
2 # _*_ conding:utf-8 _*_
3
4 """
5 test class
6 author : abeen
7 email : abeen_8298@msn.com
8 """
9
10 class MyFile:
11 """ class """
12 def __init__ (self, file_full_name):
13 self. __file_full_name = file_full_name
14
15 def append(self, value):
16 """ append """
17 current_file = open(self. __file_full_name , ' a ' )
18 current_file.write(value)
19 current_file.close()
20
21 def content(self):
22 """ content """
23 current_file = open(self. __file_full_name , ' r ' )
24 return current_file.read()
代码分析：
abeen@localhost:~/learn_test/file$ pylint file_test.py
No config file found, using default configuration
Report
======
10 statements analysed.
Raw metrics
-----------
+----------+-------+------+---------+-----------+
|type |number |% |previous |difference |
+==========+=======+======+=========+===========+
|code |11 |45.83 |11 |= |
+----------+-------+------+---------+-----------+
|docstring |8 |33.33 |8 |= |
+----------+-------+------+---------+-----------+
|comment |2 |8.33 |2 |= |
+----------+-------+------+---------+-----------+
|empty |3 |12.50 |3 |= |
+----------+-------+------+---------+-----------+
Duplication
-----------
+-------------------------+------+---------+-----------+
| |now |previous |difference |
+=========================+======+=========+===========+
|nb duplicated lines |0 |0 |= |
+-------------------------+------+---------+-----------+
|percent duplicated lines |0.000 |0.000 |= |
+-------------------------+------+---------+-----------+
Statistics by type
------------------
+---------+-------+-----------+-----------+------------+---------+
|type |number |old number |difference |%documented |%badname |
+=========+=======+===========+===========+============+=========+
|module |1 |1 |= |100.00 |0.00 |
+---------+-------+-----------+-----------+------------+---------+
|class |1 |1 |= |100.00 |0.00 |
+---------+-------+-----------+-----------+------------+---------+
|method |3 |3 |= |100.00 |0.00 |
+---------+-------+-----------+-----------+------------+---------+
|function |0 |0 |= |0.00 |0.00 |
+---------+-------+-----------+-----------+------------+---------+
Messages by category
--------------------
+-----------+-------+---------+-----------+
|type |number |previous |difference |
+===========+=======+=========+===========+
|convention |0 |0 |= |
+-----------+-------+---------+-----------+
|refactor |0 |0 |= |
+-----------+-------+---------+-----------+
|warning |0 |0 |= |
+-----------+-------+---------+-----------+
|error |0 |0 |= |
+-----------+-------+---------+-----------+
Global evaluation
-----------------
Your code has been rated at 10.00/10 (previous run: 10.00/10)
Pylint 的常用命令行参数
* -h,--help
显示所有帮助信息。
* --generate-rcfile
可以使用 pylint --generate-rcfile 来生成一个配置文件示例。可以使用重定向把这个配置文件保存下来用做以后使用。也可以在前面加上其它选项，使这些选项的值被包含在这个产生的配置文件里。如：pylint --persistent=n --generate-rcfile > pylint.conf，查看 pylint.conf，可以看到 persistent=no，而不再是其默认值 yes。
* --rcfile=<file>
指定一个配置文件。把使用的配置放在配置文件中，这样不仅规范了自己代码，也可以方便地和别人共享这些规范。
* -i <y_or_n>, --include-ids=<y_or_n>
在输出中包含 message 的 id, 然后通过 pylint --help-msg=<msg-id>来查看这个错误的详细信息，这样可以具体地定位错误。
* -r <y_or_n>, --reports=<y_or_n>
默认是 y, 表示 Pylint 的输出中除了包含源代码分析部分，也包含报告部分。
* --files-output=<y_or_n>
将每个 module /package 的 message 输出到一个以 pylint_module/package. [txt|html] 命名的文件中，如果有 report 的话，输出到名为 pylint_global.[txt|html] 的文件中。默认是输出到屏幕上不输出到文件里。
* -f <format>, --output-format=<format>
设置输出格式。可以选择的格式有 text, parseable, colorized, msvs (visual studio) 和 html, 默认的输出格式是 text。
* --disable-msg= <msg ids>
禁止指定 id 的 message. 比如说输出中包含了 W0402 这个 warning 的 message, 如果不希望它在输出中出现，可以使用 --disable-msg= W0402
源代码分析：
对于每一个 Python 模块，Pylint 的结果中首先显示一些"*"字符 , 后面紧跟模块的名字，然后是一系列的 message, message 的格式如下：
MESSAGE_TYPE: LINE_NUM:[OBJECT:] MESSAGE
MESSAGE_TYPE 有如下几种：
(C) 惯例。违反了编码风格标准
(R) 重构。写得非常糟糕的代码。
(W) 警告。某些 Python 特定的问题。
(E) 错误。很可能是代码中的错误。
(F) 致命错误。阻止 Pylint 进一步运行的错误。
报告部分：
在源代码分析结束后面，会有一系列的报告，每个报告关注于项目的某些方面，如每种类别的 message 的数目，模块的依赖关系等等。具体来说，报告中会包含如下的方面：
o 检查的 module 的个数。
o 对于每个 module, 错误和警告在其中所占的百分比。比如有两个 module A 和 B, 如果一共检查出来 4 个错误，1 个错误是在 A 中，3 个错误是在 B 中，那么 A 的错误的百分比是 25%, B 的错误的百分比是 75%。
o 错误，警告的总数量。
下面是python 常量、变量、类名等 各种命名规则.
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