I've learned. I'll share.

October 22, 2009

Introducing pyrec: The cure to the bane of __init__

I finally discovered how cool github is, and have started putting some code up there. My first entry is Record.py. I'm calling it the cure to the bane of __init__" because

  1. Mutable data structures are a bane to concurrent (multi-threaded) code.
  2. Writing self.foo = foo, self.bar = bar, etc, is a huge waste of time.
  3. When you have lots of data structures in memory, tuple-based data uses 1/4 the memory of class-based data.
As you can probably tell from my blog, I've experimented with a lot of wacky programming ideas and bending Python in ways it was never intended. But if there's one experiment that's been a success, it's Record.py. I use it for almost all of my classes. It's just so easy to use. I'm calling it "pyrec" because it's easier to write, google, etc.

So, go to the github repo or use it by following the really easy steps:

  1. Download Record.py from http://github.com/pthatcher/pyrec/blob/master/Record.py
  2. put from Record import Record at the top of your code.
  3. make a class by saying something like class Person(Record("name", "age"))
  4. Never write __init__ again (unless you want mutability).

Update: A commenter (thanks Dan!) pointed out that this is a lot like namedtuple, added in python 2.6. He asked why use this instead of namedtuple. Well, I have to admit that I probably would have never created pyrec if namedtuple existed 3 years ago. I try to avoid NIH syndrome. But it didn't exist, so I wrote pyrec. But I've been using pyrec for three years, so I have some experience on some little things that make a big difference (to me). Here are a few advantages pyrec has over namedtuple:

  1. It has a nicer interface. I prefer new(val1, val2) to _make([val1, val2]), alter to _update, and class Person(Record("name", "age")) to Person = namedtuple("Person", "name, age")
  2. I added the setField methods. That's what I use 90% of the time. Only about 10% of the time do I use alter. setField is a lot more convenient.
  3. With pyrec, you can safely override __iter__ and __getitem__. For example, in Record.py, you'll see the implementation of a LinkedList. I tried doing that with namedtuple, but the overidden __getitem__ clobers the name lookup and __iter__ the tuple unpacking.
  4. You can use tuple.__iter__(rec) to get around the latter, but pyrec's .values is a lot nicer.
  5. pyrec has .namedValues for ordered (field, value) pairs, unlike _asdict() which throws out the order. For many things I use pyrec for, this matters.
  6. You can improve it! Have looked at the code for namedtuple? Ugly. This is pretty clean, so you can improve it very easily if you need additional functionality which will work with all of your records.
If you don't care about those things, use namedtuple. It's still way better than mutable classes. But having used pyrec for three years, these little things matter to me, and so I'm still going to use pyrec. But if you want most of both worlds, I added NamedTuple to pyrec, which is a subclass of namedtuple which adds most of the pyrec goodness (everything but safe __getitem__ overloading). Thanks for update, Dan.


  1. Is there a compelling reason to prefer pyrec to collections.namedtuple? The latter is part of the standard library in versions 2.6 and above, and works just fine in 2.5.

    Either way, death to mutability-by-default!

    1. IEEE Final Year projects Project Centers in India are consistently sought after. Final Year Students Projects take a shot at them to improve their aptitudes, while specialists like the enjoyment in interfering with innovation. For experts, it's an alternate ball game through and through. Smaller than expected IEEE Final Year project centers ground for all fragments of CSE & IT engineers hoping to assemble. Final Year Projects for CSE It gives you tips and rules that is progressively critical to consider while choosing any final year project point.

      JavaScript Online Training in India

      JavaScript Training in India

      The Angular Training covers a wide range of topics including Components, Angular Directives, Angular Services, Pipes, security fundamentals, Routing, and Angular programmability. The new Angular TRaining will lay the foundation you need to specialise in Single Page Application developer. Angular Training

  2. Dan, I updated the post to answer your question. Thanks for brining it up. I'm still in python 2.5 land and had forgotten about additions to 2.6 like namedtuple.

  3. Thanks for the comprehensive reply. pyrec's interface definitely looks nicer, particularly the support for overriding __getitem__ - namedtuple fails rather ungracefully in that department. I'll have to give a pyrec a spin.

  4. Interesting.

    One point: setField instead of set_field:
    1) conflicts with PEP 008
    2) breaks capitalization, breaks consistency. You know, attribute name is 'foo', setter is 'setFoo'.

    I'm using this:

    class Record(dict): pass

    foo = Record(g=50)

    If you change dict to FrozenDict, it will become immutable. But tuples take less memory, yeah.

    P.S.: "Your HTML cannot be accepted: Tag is not allowed: CODE" What's wrong with the most useful tag? And it doesn't accept PRE either. Jesus, even Q is not allowed.

  5. Temoto, good point about the method names. PEP008 specifically says:

    "mixedCase is allowed only in contexts where that's already the prevailing style (e.g. threading.py), to retain backwards compatibility."

    I've been using mixedCase for all of my code for years because of "prevailing style". And I forgot that most python developers use underscore_case.

    So, in order to fix this, I've changed pyrec from mixedCase to underscore_case go see it at http://github.com/pthatcher/pyrec. Thanks for the heads-up.

  6. Your article is very good and useful, thank you very much for this content. : see more

  7. I like the post format as you create user engagement in the complete article. It seems round up of all published posts. Thanks for gauging the informative posts.
    cara menggugurkan kandungan
    obat aborsi
    kalkulator kehamilan
    tanda tanda kehamilan


  8. شركة غسيل خزانات بالمدينة المنورة و عمال مروبون وحاصلون على شهادة صحية فقط اتصل بنا لتحصل على افضل خدمة غسيل خزانات

  9. This comment has been removed by the author.

  10. You want to tell the story a month ago I found this site and at first nothing worked out for me and then I thought of everything and now I spend all my free time on this site ravishing new online casino Do everything meaningfully and you will succeed

  11. Nice Blog, thank you so much for sharing such an amazing information with us.
    Website Designing Company in Delhi

  12. Thank You! For sharing such a great article, It’s been a amazing article.
    It’s provide lot’s of information, I really enjoyed to read this.

  13. Nice blog, you put valuable information in your blog. I’m really thankful to you for sharing this blog with us. Ogen Information is one of the best Website Designing Company in Delhi.
    Website Designing Company in Delhi

  14. Your content in this blog is really impressive, I’m really thankful to you for this information. Visit Y&H Cargo for Shipping and Freight Forwarding Services.
    Logistics Company in Delhi

  15. I feel happy about and learning more about this topic. keep sharing your information regularly for my future reference. This content creates new hope and inspiration within me. Thanks for sharing an article like this. the information which you have provided is better than another blog.
    Best IELTS Coaching institute in Dwarka
    Best IELTS Coaching centre in Dwarka

  16. Nice blog, get Fleet Painting and Vinyl Signage Printing Service by Kalakutir Pvt Ltd.
    Fleet Painting


  17. هل تبحث عن شركة متخصصة فى خدمات التنظيف بالدمام بافضل المعدات والسوائل وثقة تمة فى العمل ودقة فى النتائج كل هذه المميزات توفرها شركة الجنرال الشركة الافضل والامثل فى الخدمات المنزلية بالدمام وبما اننا الشركة الافضل والامثل بدون منافس سوف نسعى لتوفر افضل الخدمات باقل تكلفة وبقدر كبير من الاهتمام والدقة عزيزى اينما كنت فى اى منطقة ا وحى تابع لمدينة الدمام اتصل بنا وسوف نصلك فى الحال شركة االجنرال للخدمات المنزلية
    شركة نقل عفش بالدمام

    شركة تسليك مجاري بالدمام

    شركة مكافحة حشرات بالدمام

    شركة تنظيف منازل بالدمام ومجالس وكنب وشقق

    شركة مكافحه نمل ابيض بالدمام بافضل المبيدات

    شركة تنظيف مجالس وكنب بالدمام بافضل مواد التنظييف

    شركة تنظيف خزانات بالدمام مع التعقيم والغسيل

    شركة تنظيف سجاد بالدمام بالبخار

    شركة تنظيف شقق بالدمام وفلل وقصور


  18. شركة تركيب غرف نوم بالمدينة المنورة
    تعتبر شركة تركيب غرف نوم بالمدينة المنورة من كبرى الشركات التي تساعد الكثيرون في عمليات فك وتركيب غرف النوم، فمن الصعب على العملاء أن يقوموا بمثل هذه الأعمال لأنها تحتاج إلى متخصصون لديهم القدرة الفائقة في تركيب غرف النوم بمختلف أنواعها وأحجامها، ومن ضمن الكوادر التي تعتمد عليها شركة تركيب غرف نوم نجار بالمدينة المنورة المنورة فهم من العاملين بالشركة والتي تعتمد عليهم بشكل كبير في تنفيذ مثل هذه الأعمال الصعبة والتي تحتاج إلى أشخاص ذات خبرة طويلة وكبيرة في هذا المجال، كما أن شركة تركيب غرف نوم بالمدينة المنورة تقدم معدات وأدوات حديثة تساعد على تسهيل عملية تركيب غرف النوم والانتهاء في وقت وجيز ولا تحتاج هذه العملية إلى لإثنان فقط من عمال شركتنا الهمام.

  19. Usually I never comment on blogs but your article is so convincing that I never stop myself to say something about it. You’re doing a great job Man,Keep it up.
    study in canada
    ielts coaching in gurgaon

  20. Thank you so much dear for sharing such an amazing blog with us.
    Website Designing Company in India

  21. Nice blog, get an amazing Detective Services by Gribety Detective India in Jaipur and Bhopal.
    Detective Agency in Jaipur

  22. Sarswati Enterprises provide the best Pilfer Proof Caps and Aluminum caps & Closures Machinery in Delhi, India.
    Pilfer Proof Caps Making Machinery

  23. Put more informative things on this blog page, and thanks for sharing this. Visit Noble IVF for best Fertility treatment in Aligarh, India.
    IVF Centre in Aligarh

  24. Thank you so much dear for sharing such an amazing blog with us.

  25. Thanks for sharing your wealthy information. This is one of the excellent posts which I have seen. I have gone through all of your blogs, but this blog is the best one. I hope in future you will continue sharing such an excellent post. To know more visit: Mobile App Development Company usa

  26. Indian Web Designers fast-growing website designing company in Delhi intend to create a website on your request according to your specifications.
    Web Design Company in Delhi
    Digital Marketing company in india

  27. Energy Saving Sensors Made by Highly Components Pvt. Ltd. - Which is the leading company in the field of Security related products in India. The company has achieved an unrivalled position in the market by introducing PIR Motion Sensors for automatic control of lights apart from other Security Sensors. Energy Saving Sensors in New Delhi
    Smoke Alarm Sensor

  28. Tekniko Global provides mobile app development company in noida for iPhone, iPad, Android, Blackberry & Windows 7 platforms including Xamarin for cross platform mobile development.
    mobile app development company in noida

  29. Appslure is a high rated Mobile Game development company in Delhi. We are no 1 company for IOS & Android games.
    Game Development company in Delhi

  30. I thank you for the information and articles you provided

  31. I was not aware of such updating about the lesson but Now I am very excited to read this information and I hope this post will improve my teaching and writing ability
    buy dissertation online uk

  32. i am a beginner python learner so i was facing issue with mutable data structures being bane to concurrent code. thanks for sharing your experiments on record.py it has helped me alot.

  33. Put more informative things on this blog page. Clear basis concept and thanks for sharing this.

  34. PHP advancement is a well-known scripting language that is utilized to make intelligent and dynamic sites. Today, most business sites are made by utilizing php application development as it accompanies profoundly practical highlights and ease of use. So, organizations ready to make a customer's site with amazing information the executives highlights will require to recruit php development company. Our prime php website development improvement administrations start with understanding the client needs and stretches out to database driven top of the line custom undertaking web frameworks. Recruit devoted PHP engineers from Colan Infotech to plan php web development utilizing Photoshop, Flash etc. The php development India advancement administrations we offer are recorded underneath:

  35. The best php application development company in India. We contribute high quality custom php website development services from our well-trained team. Get to know more about the php development company in Chennai Reach us or just give a call to us for php development.

  36. Select the option of Assignment Help when you don’t want to take the stress of writing your assignments or homework. This option allows you to get experts’ assistance for composing your academic papers even in adverse conditions. You can take the online help of academic writers at any time using these kinds of services. If you can’t pay attention to homework writing or don’t have enough time, this option will help you a lot. Handle everything for composing your papers even in adverse conditions via online academic writing services.
    Help Assignment
    Assignment Help Company

  37. I am really very happy to visit your blog. Now I am found which I actually want. I check your blog every day and try to learn something from your blog. Please keep us up to date like this. Thanks for sharing.
    Also, we are giving 100% support after delivering the project. If you have any requirements regarding Blockchain, Iot, Ai, Travel Portal Development then you can contact us at +1 (415) 890 8990, +91 9500 069 296.
    Travel Portal Development

  38. Place an order for Assignment Help in Singapore so you can connect with professional writers. Pay a good amount to buy the services of online assignment help even in Singapore.

  39. Need Home Security System India for Home and Office, Contact DFS Services. Buy High Quality Home Security Intruder Alarm System or Burglar Alarm System, Video Doorbell and Security Cameras (IP Camera). Dfs Services is the best company for Home Security Systems in India.

    visit us:-home security system Bangalore

    security alarm

  40. This is truly an practical and pleasant information for all. Thanks for sharing this to us
    buy electronics online pakistan

    Tejar is Pakistan’s top e-commerce store that deals in genuine and reliable consumer goods belonging to numerous brands and product categories.

  41. Great content I love it Coursework Help Satta.

  42. Tekniko Global is an award-winning mobile app development company in Delhi and other city or countries. We develop high-quality.

  43. cool, please guidance so that I can create a blog like yours

  44. It is the popular satta game which has been played both offline and online by satta players in all the parts of the country.
    Thanks for sharing your thoughts. I truly appreciate your efforts and I will be waiting for your next write ups thank you once again.
    sattaking-sattaking game is drawing and lottery based mostly game,how ever currently it's categorized in gambling,
    and satta king currently terribly renowned and largely taking part in game across the globe individuals ar crazy regarding this game.
    But currently the foremost necessary factor is that this game is failed to follow the law and rule regulation that to follow the protocols and rule.
    Now currently individuals want to rely on it, if the sport does not follow the protocols they need not play the sports however individuals ar still taking part in the game,
    they play the games on the QT, individuals have rely on it to stop taking part in this type of games, always aid work and facilitated people that would like facilitated,
    do something for your nation do forever sensible thing and be forever happy.This iѕ the right site for anyone who would like too
    find out about this topic. Great website,thanks.Do you exactly know what is Satta King ? Maybe You do or maybe you don't. If you don't know about it then you are at right place.
    We will discuss everything related to the game here.

  45. someone is using your domain to send pathetic fake hacker ransom notes

  46. Advantage of Assignment Help is knowledge enhancement. When you can’t answer any question or find any subject tough to handle, you can’t prepare complete assignments.

  47. Wow. I am giving 5 out 5 stars to this information. Thanks a ton from my side


  48. Appslure is an award-winning mobile app development company building feature-packed and interactive mobile applications for startups, medium and large enterprises.


Blog Archive

Google Analytics