docs:pep-0008
اختلافات
عرض الاختلافات بين النسخة المختارة و النسخة الحالية من الصفحة.
جانبي المراجعة السابقةالمراجعة السابقة | |||
docs:pep-0008 [2010/03/30 09:11] – تدقيق لغوي djilani | docs:pep-0008 [2015/04/23 03:20] (حالي) – تحرير خارجي 127.0.0.1 | ||
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سطر 1: | سطر 1: | ||
+ | {{tag> | ||
+ | ====== دليل تنسيق كود بايثون ====== | ||
+ | |||
+ | ===== حول هذه الوثيقة ===== | ||
+ | |||
+ | |||
+ | هذا المقال مترجم عن | ||
+ | |||
+ | * المقال الأصلي : [[http:// | ||
+ | |||
+ | * الرخصة : ملكية عامة مشاع - Public domain | ||
+ | |||
+ | |||
+ | ====== مقدمة ====== | ||
+ | |||
+ | هذه الوثيقة بمثابة قواعد لتنسيق الكود في مكتبة الإصدار الرسميّ لبايثون. | ||
+ | |||
+ | |||
+ | هذه الوثيقة مبنيّة على Guido' | ||
+ | و عند التعارض أعتُمد على وثيقة جيدو و الوثيقة ما زالت غير مكتملة و لربما لن تكتمل أبدا ;-). | ||
+ | |||
+ | |||
+ | ====== الاتساق الأعمى ====== | ||
+ | |||
+ | من أراء جيدو الأساسية " | ||
+ | |||
+ | دليل التنسيق أساسه الاتساق فالتوافق مع دليل التنسيق مهم جدا و لكن الاتساق داخل المشروع أكثر أهمية و الاتساق مع وحدة أو دالة ما هو الأكثر أهمية على الإطلاق . | ||
+ | |||
+ | من المهم جدا أن تعرف كيف تتوافق مع الأشياء -- ففي بعض الأحيان دليل التنسيق لن ينطبق و هنا عليك أن تستخدم قدراتك بالإضافة للإطلاع على الأمثلة لتقرّر ما هو الأفضل ولا تترد أبدا في السؤال!. | ||
+ | |||
+ | == سببين جيدين لكسر قاعدة معينة: == | ||
+ | |||
+ | - إذا كان تطبيق القواعد سيجعل الكود أقل قابلية للقراءة حتى بالنسبة لشخص تعوّد على قراءة الأكواد المتبعة للقواعد. | ||
+ | |||
+ | - عدم كسر التوافقية مع باقي الكود الذي يكسر القواعد أيضا- ربما لأسباب تاريخية - بالرغم من أنها فرصة لتنظيف الكود ككل. | ||
+ | |||
+ | |||
+ | ====== النسق ====== | ||
+ | |||
+ | |||
+ | |||
+ | == الإزاحة (indentation) == | ||
+ | |||
+ | استخدم 4 مسافات لكل مستوى إزاحة. | ||
+ | |||
+ | == المسافات أم الألسنة | ||
+ | |||
+ | لا تقم أبدا بالخلط في استخدام المسافات والألسنة . | ||
+ | |||
+ | الوسيلة الأكثر شعبية في بايثون للإزاحات هي استخدام المسافات فقط والطريقة الثانية في ترتيب شعبية الاستعمال هي استخدام الألسنة وحدها لهذا يجب تعديل الكود الذي تستخدم فيه إزاحات مختلطة من المسافات والألسنة ليصبح مسافات فقط . | ||
+ | |||
+ | عند استدعاء مفسر البايثون من سطر الأوامر مع الخاصية t- سيخرج لك تحذيرات بخصوص استخدام خليط من المسافات والألسنة، أما عند استخدام tt- فهذه التحذيرات ستعتبر أخطاء. لذ يوصى بشدة باستعمال هذه الخواص . | ||
+ | |||
+ | |||
+ | == الطول الأقصى للسطر | ||
+ | |||
+ | حدد الطول الأقصى لكل سطر ب 79 حرف . | ||
+ | |||
+ | لا يزال إلى الآن توجد العديد من الأجهزة المحدودة ب 80 حرف للسطر بالإضافة إلى أن تحديد النافذة ب 80 يجعل بالإمكان الحصول على عدة نوافذ متجانبة | ||
+ | (warping)الافتراضي على هذه الأجهزة يفسد هيكلية عرض الكود و يصعّب قراءته وفهمه .لذا فضلا حدّد الطول الأقصى لكل سطر ب 79 حرفا. أما بالنسبة للوحدات الطويلة من النصوص مثل docstrings أو التعليقات يفضل تحديد الطول الأقصى ب 72 حرفا . | ||
+ | |||
+ | الطريقة المثلى في طي سطور النصوص الطويلة هي استخدام الخط المائل \ و الأقواس . تأكد من إزاحة السطر الجديد بشكل مناسب. الوسيلة المثلى للطي حول العوامل - مثل == ,=< - هي الطي **بعدها** مباشرة وليس قبلها . | ||
+ | |||
+ | أمثلة على الطي : | ||
+ | |||
+ | <code python> | ||
+ | class Rectangle(Blob): | ||
+ | |||
+ | def __init__(self, | ||
+ | | ||
+ | if width == 0 and height == 0 and \ | ||
+ | color == ' | ||
+ | | ||
+ | raise ValueError(" | ||
+ | if width == 0 and height == 0 and (color == ' | ||
+ | | ||
+ | raise ValueError(" | ||
+ | | ||
+ | Blob.__init__(self, | ||
+ | color, emphasis, highlight) | ||
+ | |||
+ | </ | ||
+ | |||
+ | ==الأسطر الفارغة== | ||
+ | |||
+ | افصل بين الدوال الرئيسة والكلاسات بسطرين فارغين | ||
+ | |||
+ | تعريف ال method داخل كلاس تفصل بسطر فارغ واحد . | ||
+ | |||
+ | يمكن استخدام الأسطر الفارغة (برُشد) لفصل مجموعات من الدوال مترابطة المضمون . | ||
+ | |||
+ | استعمل الأسطر الفارغة داخل الدوال (برُشد) لتحديد الأقسام المنطقية . | ||
+ | |||
+ | تتعامل بايثون مع control-L (^L) كمسافة .بينما تعاملها مع العديد من الأدوات كفواصل للصفحات. لذا بإمكانك استخدامها لتنظيم الكود إلى أقسام وصفحات . | ||
+ | |||
+ | |||
+ | === الترميز | ||
+ | |||
+ | |||
+ | Code in the core Python distribution should aways use the ASCII or | ||
+ | Latin-1 encoding (a.k.a. ISO-8859-1). | ||
+ | UTF-8 is preferred over Latin-1, see PEP 3120. | ||
+ | |||
+ | Files using ASCII (or UTF-8, for Python 3.0) should not have a | ||
+ | coding cookie. | ||
+ | comment or docstring needs to mention an author name that requires | ||
+ | Latin-1; otherwise, using \x, \u or \U escapes is the preferred | ||
+ | way to include non-ASCII data in string literals. | ||
+ | |||
+ | For Python 3.0 and beyond, the following policy is prescribed for | ||
+ | the standard library (see PEP 3131): All identifiers in the Python | ||
+ | standard library MUST use ASCII-only identifiers, | ||
+ | English words wherever feasible (in many cases, abbreviations and | ||
+ | technical terms are used which aren't English). In addition, | ||
+ | string literals and comments must also be in ASCII. The only | ||
+ | exceptions are (a) test cases testing the non-ASCII features, and | ||
+ | (b) names of authors. Authors whose names are not based on the | ||
+ | latin alphabet MUST provide a latin transliteration of their | ||
+ | names. | ||
+ | |||
+ | Open source projects with a global audience are encouraged to | ||
+ | adopt a similar policy. | ||
+ | |||
+ | |||
+ | |||
+ | |||
+ | |||
+ | ====== الاستيراد ====== | ||
+ | |||
+ | |||
+ | - Imports should usually be on separate lines, e.g.: | ||
+ | |||
+ | Yes: import os | ||
+ | import sys | ||
+ | |||
+ | No: import sys, os | ||
+ | |||
+ | it's okay to say this though: | ||
+ | |||
+ | from subprocess import Popen, PIPE | ||
+ | |||
+ | - Imports are always put at the top of the file, just after any module | ||
+ | comments and docstrings, and before module globals and constants. | ||
+ | |||
+ | Imports should be grouped in the following order: | ||
+ | |||
+ | 1. standard library imports | ||
+ | 2. related third party imports | ||
+ | 3. local application/ | ||
+ | |||
+ | You should put a blank line between each group of imports. | ||
+ | |||
+ | Put any relevant __all__ specification after the imports. | ||
+ | |||
+ | - Relative imports for intra-package imports are highly discouraged. | ||
+ | Always use the absolute package path for all imports. | ||
+ | Even now that PEP 328 [7] is fully implemented in Python 2.5, | ||
+ | its style of explicit relative imports is actively discouraged; | ||
+ | absolute imports are more portable and usually more readable. | ||
+ | |||
+ | - When importing a class from a class-containing module, it's usually okay | ||
+ | to spell this | ||
+ | |||
+ | from myclass import MyClass | ||
+ | from foo.bar.yourclass import YourClass | ||
+ | |||
+ | If this spelling causes local name clashes, then spell them | ||
+ | |||
+ | import myclass | ||
+ | import foo.bar.yourclass | ||
+ | |||
+ | and use " | ||
+ | |||
+ | |||
+ | |||
+ | ====== المسافات البيضاء فى التعابير و الجمل البرمجية ====== | ||
+ | |||
+ | |||
+ | Pet Peeves | ||
+ | |||
+ | Avoid extraneous whitespace in the following situations: | ||
+ | |||
+ | - Immediately inside parentheses, | ||
+ | |||
+ | Yes: spam(ham[1], | ||
+ | No: spam( ham[ 1 ], { eggs: 2 } ) | ||
+ | |||
+ | - Immediately before a comma, semicolon, or colon: | ||
+ | |||
+ | Yes: if x == 4: print x, y; x, y = y, x | ||
+ | No: if x == 4 : print x , y ; x , y = y , x | ||
+ | |||
+ | - Immediately before the open parenthesis that starts the argument | ||
+ | list of a function call: | ||
+ | |||
+ | Yes: spam(1) | ||
+ | No: spam (1) | ||
+ | |||
+ | - Immediately before the open parenthesis that starts an indexing or | ||
+ | slicing: | ||
+ | |||
+ | Yes: dict[' | ||
+ | No: dict [' | ||
+ | |||
+ | - More than one space around an assignment (or other) operator to | ||
+ | align it with another. | ||
+ | |||
+ | Yes: | ||
+ | |||
+ | x = 1 | ||
+ | y = 2 | ||
+ | long_variable = 3 | ||
+ | |||
+ | No: | ||
+ | |||
+ | x = 1 | ||
+ | y = 2 | ||
+ | long_variable = 3 | ||
+ | |||
+ | ==توصيات أخرى== | ||
+ | |||
+ | |||
+ | - Always surround these binary operators with a single space on | ||
+ | either side: assignment (=), augmented assignment (+=, -= etc.), | ||
+ | comparisons (==, <, >, !=, <>, <=, >=, in, not in, is, is not), | ||
+ | Booleans (and, or, not). | ||
+ | |||
+ | - Use spaces around arithmetic operators: | ||
+ | |||
+ | Yes: | ||
+ | |||
+ | i = i + 1 | ||
+ | submitted += 1 | ||
+ | x = x * 2 - 1 | ||
+ | hypot2 = x * x + y * y | ||
+ | c = (a + b) * (a - b) | ||
+ | |||
+ | No: | ||
+ | |||
+ | i=i+1 | ||
+ | submitted +=1 | ||
+ | x = x*2 - 1 | ||
+ | hypot2 = x*x + y*y | ||
+ | c = (a+b) * (a-b) | ||
+ | |||
+ | - Don't use spaces around the ' | ||
+ | keyword argument or a default parameter value. | ||
+ | |||
+ | Yes: | ||
+ | |||
+ | def complex(real, | ||
+ | return magic(r=real, | ||
+ | |||
+ | No: | ||
+ | |||
+ | def complex(real, | ||
+ | return magic(r = real, i = imag) | ||
+ | |||
+ | - Compound statements (multiple statements on the same line) are | ||
+ | generally discouraged. | ||
+ | |||
+ | Yes: | ||
+ | |||
+ | if foo == ' | ||
+ | do_blah_thing() | ||
+ | do_one() | ||
+ | do_two() | ||
+ | do_three() | ||
+ | |||
+ | Rather not: | ||
+ | |||
+ | if foo == ' | ||
+ | do_one(); do_two(); do_three() | ||
+ | |||
+ | While sometimes it's okay to put an if/ | ||
+ | body on the same line, never do this for multi-clause | ||
+ | statements. | ||
+ | |||
+ | Rather not: | ||
+ | |||
+ | if foo == ' | ||
+ | for x in lst: total += x | ||
+ | while t < 10: t = delay() | ||
+ | |||
+ | Definitely not: | ||
+ | |||
+ | if foo == ' | ||
+ | else: do_non_blah_thing() | ||
+ | |||
+ | try: something() | ||
+ | finally: cleanup() | ||
+ | |||
+ | do_one(); do_two(); do_three(long, | ||
+ | list, like, this) | ||
+ | |||
+ | if foo == ' | ||
+ | |||
+ | ====== التعليقات ====== | ||
+ | |||
+ | |||
+ | Comments that contradict the code are worse than no comments. | ||
+ | a priority of keeping the comments up-to-date when the code changes! | ||
+ | |||
+ | Comments should be complete sentences. | ||
+ | sentence, its first word should be capitalized, | ||
+ | that begins with a lower case letter (never alter the case of | ||
+ | identifiers!). | ||
+ | |||
+ | If a comment is short, the period at the end can be omitted. | ||
+ | comments generally consist of one or more paragraphs built out of complete | ||
+ | sentences, and each sentence should end in a period. | ||
+ | |||
+ | You should use two spaces after a sentence-ending period. | ||
+ | |||
+ | When writing English, Strunk and White apply. | ||
+ | |||
+ | Python coders from non-English speaking countries: please write | ||
+ | your comments in English, unless you are 120% sure that the code | ||
+ | will never be read by people who don't speak your language. | ||
+ | |||
+ | |||
+ | == Block Comments == | ||
+ | |||
+ | Block comments generally apply to some (or all) code that follows them, | ||
+ | and are indented to the same level as that code. Each line of a block | ||
+ | comment starts with a # and a single space (unless it is indented text | ||
+ | inside the comment). | ||
+ | |||
+ | Paragraphs inside a block comment are separated by a line containing a | ||
+ | single #. | ||
+ | |||
+ | ==التعليق المضمن فى السطر | ||
+ | |||
+ | |||
+ | تستعمل بترشيد . | ||
+ | التعليقات المضمنة فى السطر يجب أن يسبقها مسافتين على الاقل من الجملة البرمجية | ||
+ | و يجب أن تُبدأ ب # و بعدها مسافة واحدة | ||
+ | |||
+ | التعليقات المضمنة غير مهمة فى الحقيقة بل هى مشتِتة إن كانت تشرح ما هو واضح . | ||
+ | |||
+ | لا تفعل التالى : | ||
+ | |||
+ | |||
+ | x = x + 1 # Increment x | ||
+ | | ||
+ | x = x + 1 # Compensate for border | ||
+ | |||
+ | |||
+ | ====== نصوص التوثيق Docstrings====== | ||
+ | |||
+ | |||
+ | |||
+ | Conventions for writing good documentation strings (a.k.a. " | ||
+ | are immortalized in PEP 257 [3]. | ||
+ | |||
+ | Write docstrings for all public modules, functions, classes, and | ||
+ | methods. | ||
+ | should have a comment that describes what the method does. This comment | ||
+ | should appear after the " | ||
+ | |||
+ | PEP 257 describes good docstring conventions. | ||
+ | importantly, | ||
+ | by itself, and preferably preceded by a blank line, e.g.: | ||
+ | |||
+ | |||
+ | """ | ||
+ | |||
+ | Optional plotz says to frobnicate the bizbaz first. | ||
+ | |||
+ | """ | ||
+ | |||
+ | For one liner docstrings, it's okay to keep the closing """ | ||
+ | line. | ||
+ | |||
+ | |||
+ | ====== Version Bookkeeping ====== | ||
+ | |||
+ | |||
+ | If you have to have Subversion, CVS, or RCS crud in your source file, do | ||
+ | it as follows. | ||
+ | |||
+ | __version__ = " | ||
+ | # $Source$ | ||
+ | |||
+ | These lines should be included after the module' | ||
+ | other code, separated by a blank line above and below. | ||
+ | |||
+ | |||
+ | |||
+ | ====== Naming Conventions ====== | ||
+ | |||
+ | |||
+ | |||
+ | |||
+ | The naming conventions of Python' | ||
+ | never get this completely consistent -- nevertheless, | ||
+ | currently recommended naming standards. | ||
+ | (including third party frameworks) should be written to these standards, | ||
+ | but where an existing library has a different style, internal consistency | ||
+ | is preferred. | ||
+ | |||
+ | == Descriptive: | ||
+ | |||
+ | |||
+ | There are a lot of different naming styles. | ||
+ | recognize what naming style is being used, independently from what they | ||
+ | are used for. | ||
+ | |||
+ | The following naming styles are commonly distinguished: | ||
+ | |||
+ | - b (single lowercase letter) | ||
+ | |||
+ | - B (single uppercase letter) | ||
+ | |||
+ | - lowercase | ||
+ | |||
+ | - lower_case_with_underscores | ||
+ | |||
+ | - UPPERCASE | ||
+ | |||
+ | - UPPER_CASE_WITH_UNDERSCORES | ||
+ | |||
+ | - CapitalizedWords (or CapWords, or CamelCase -- so named because | ||
+ | of the bumpy look of its letters[4]). | ||
+ | StudlyCaps. | ||
+ | |||
+ | Note: When using abbreviations in CapWords, capitalize all the letters | ||
+ | of the abbreviation. | ||
+ | HttpServerError. | ||
+ | |||
+ | - mixedCase (differs from CapitalizedWords by initial lowercase | ||
+ | character!) | ||
+ | |||
+ | - Capitalized_Words_With_Underscores (ugly!) | ||
+ | |||
+ | There' | ||
+ | names together. | ||
+ | completeness. | ||
+ | items traditionally have names like st_mode, st_size, st_mtime and so on. | ||
+ | (This is done to emphasize the correspondence with the fields of the | ||
+ | POSIX system call struct, which helps programmers familiar with that.) | ||
+ | |||
+ | The X11 library uses a leading X for all its public functions. | ||
+ | this style is generally deemed unnecessary because attribute and method | ||
+ | names are prefixed with an object, and function names are prefixed with a | ||
+ | module name. | ||
+ | |||
+ | In addition, the following special forms using leading or trailing | ||
+ | underscores are recognized (these can generally be combined with any case | ||
+ | convention): | ||
+ | |||
+ | - _single_leading_underscore: | ||
+ | import *" does not import objects whose name starts with an underscore. | ||
+ | |||
+ | - single_trailing_underscore_: | ||
+ | Python keyword, e.g. | ||
+ | Tkinter.Toplevel(master, | ||
+ | |||
+ | | ||
+ | |||
+ | __double_leading_and_trailing_underscore__: | ||
+ | attributes that live in user-controlled namespaces. | ||
+ | | ||
+ | as documented. | ||
+ | |||
+ | Prescriptive: | ||
+ | |||
+ | Names to Avoid | ||
+ | |||
+ | Never use the characters `l' (lowercase letter el), `O' (uppercase | ||
+ | letter oh), or `I' (uppercase letter eye) as single character variable | ||
+ | names. | ||
+ | |||
+ | In some fonts, these characters are indistinguishable from the numerals | ||
+ | one and zero. When tempted to use `l', use `L' instead. | ||
+ | |||
+ | Package and Module Names | ||
+ | |||
+ | Modules should have short, all-lowercase names. | ||
+ | in the module name if it improves readability. | ||
+ | also have short, all-lowercase names, although the use of underscores is | ||
+ | discouraged. | ||
+ | |||
+ | Since module names are mapped to file names, and some file systems are | ||
+ | case insensitive and truncate long names, it is important that module | ||
+ | names be chosen to be fairly short -- this won't be a problem on Unix, | ||
+ | but it may be a problem when the code is transported to older Mac or | ||
+ | Windows versions, or DOS. | ||
+ | |||
+ | When an extension module written in C or C++ has an accompanying Python | ||
+ | module that provides a higher level (e.g. more object oriented) | ||
+ | interface, the C/C++ module has a leading underscore (e.g. _socket). | ||
+ | |||
+ | Class Names | ||
+ | |||
+ | Almost without exception, class names use the CapWords convention. | ||
+ | Classes for internal use have a leading underscore in addition. | ||
+ | |||
+ | Exception Names | ||
+ | |||
+ | Because exceptions should be classes, the class naming convention | ||
+ | applies here. However, you should use the suffix " | ||
+ | exception names (if the exception actually is an error). | ||
+ | |||
+ | Global Variable Names | ||
+ | |||
+ | (Let's hope that these variables are meant for use inside one module | ||
+ | only.) | ||
+ | |||
+ | Modules that are designed for use via "from M import *" should use the | ||
+ | __all__ mechanism to prevent exporting globals, or use the older | ||
+ | convention of prefixing such globals with an underscore (which you might | ||
+ | want to do to indicate these globals are " | ||
+ | |||
+ | Function Names | ||
+ | |||
+ | Function names should be lowercase, with words separated by underscores | ||
+ | as necessary to improve readability. | ||
+ | |||
+ | mixedCase is allowed only in contexts where that's already the | ||
+ | prevailing style (e.g. threading.py), | ||
+ | |||
+ | Function and method arguments | ||
+ | |||
+ | Always use ' | ||
+ | |||
+ | Always use ' | ||
+ | |||
+ | If a function argument' | ||
+ | generally better to append a single trailing underscore rather than use | ||
+ | an abbreviation or spelling corruption. | ||
+ | " | ||
+ | |||
+ | Method Names and Instance Variables | ||
+ | |||
+ | Use the function naming rules: lowercase with words separated by | ||
+ | underscores as necessary to improve readability. | ||
+ | |||
+ | Use one leading underscore only for non-public methods and instance | ||
+ | variables. | ||
+ | |||
+ | To avoid name clashes with subclasses, use two leading underscores to | ||
+ | invoke Python' | ||
+ | |||
+ | Python mangles these names with the class name: if class Foo has an | ||
+ | attribute named __a, it cannot be accessed by Foo.__a. | ||
+ | user could still gain access by calling Foo._Foo__a.) | ||
+ | leading underscores should be used only to avoid name conflicts with | ||
+ | attributes in classes designed to be subclassed. | ||
+ | |||
+ | Note: there is some controversy about the use of __names (see below). | ||
+ | |||
+ | Designing for inheritance | ||
+ | |||
+ | Always decide whether a class' | ||
+ | (collectively: | ||
+ | doubt, choose non-public; it's easier to make it public later than to | ||
+ | make a public attribute non-public. | ||
+ | |||
+ | Public attributes are those that you expect unrelated clients of your | ||
+ | class to use, with your commitment to avoid backward incompatible | ||
+ | changes. | ||
+ | used by third parties; you make no guarantees that non-public attributes | ||
+ | won't change or even be removed. | ||
+ | |||
+ | We don't use the term " | ||
+ | private in Python (without a generally unnecessary amount of work). | ||
+ | |||
+ | Another category of attributes are those that are part of the " | ||
+ | API" (often called " | ||
+ | designed to be inherited from, either to extend or modify aspects of the | ||
+ | class' | ||
+ | explicit decisions about which attributes are public, which are part of | ||
+ | the subclass API, and which are truly only to be used by your base | ||
+ | class. | ||
+ | |||
+ | With this in mind, here are the Pythonic guidelines: | ||
+ | |||
+ | - Public attributes should have no leading underscores. | ||
+ | |||
+ | - If your public attribute name collides with a reserved keyword, append | ||
+ | a single trailing underscore to your attribute name. This is | ||
+ | preferable to an abbreviation or corrupted spelling. | ||
+ | notwithstanding this rule, ' | ||
+ | variable or argument which is known to be a class, especially the | ||
+ | first argument to a class method.) | ||
+ | |||
+ | Note 1: See the argument name recommendation above for class methods. | ||
+ | |||
+ | - For simple public data attributes, it is best to expose just the | ||
+ | attribute name, without complicated accessor/ | ||
+ | mind that Python provides an easy path to future enhancement, | ||
+ | you find that a simple data attribute needs to grow functional | ||
+ | behavior. | ||
+ | implementation behind simple data attribute access syntax. | ||
+ | |||
+ | Note 1: Properties only work on new-style classes. | ||
+ | |||
+ | Note 2: Try to keep the functional behavior side-effect free, although | ||
+ | side-effects such as caching are generally fine. | ||
+ | |||
+ | Note 3: Avoid using properties for computationally expensive | ||
+ | operations; the attribute notation makes the caller believe | ||
+ | that access is (relatively) cheap. | ||
+ | |||
+ | - If your class is intended to be subclassed, and you have attributes | ||
+ | that you do not want subclasses to use, consider naming them with | ||
+ | double leading underscores and no trailing underscores. | ||
+ | Python' | ||
+ | mangled into the attribute name. This helps avoid attribute name | ||
+ | collisions should subclasses inadvertently contain attributes with the | ||
+ | same name. | ||
+ | |||
+ | Note 1: Note that only the simple class name is used in the mangled | ||
+ | name, so if a subclass chooses both the same class name and attribute | ||
+ | name, you can still get name collisions. | ||
+ | |||
+ | Note 2: Name mangling can make certain uses, such as debugging and | ||
+ | __getattr__(), | ||
+ | is well documented and easy to perform manually. | ||
+ | |||
+ | Note 3: Not everyone likes name mangling. | ||
+ | need to avoid accidental name clashes with potential use by | ||
+ | advanced callers. | ||
+ | |||
+ | |||
+ | |||
+ | ====== المصادر ====== | ||
+ | |||
+ | - | ||
+ | - | ||
+ | - | ||
+ | - | ||
+ | - | ||
+ | - | ||
+ | - | ||
+ | |||
+ | ======حقوق النسخ====== | ||
+ | ترخص هذه الوثيقة كملكية عامة مشاع - Public domain |
docs/pep-0008.txt · آخر تعديل: 2015/04/23 03:20 (تحرير خارجي)