What should I learn to build an automatic shift scheduler in Python? - python

So I've been self-learning Python through this app and I've gotten through the course it offers. I feel like I have a good grasp on the absolute basics of the language, but I still have no idea how to actually use it to solve real problems, ie do actually useful things. I feel like I have a bunch of building blocks but I don't know how to put them together.
So enter my job. I'm a student that works part time and we do weekly schedule requests by paper. It's a giant pain for both us and the supervisors who do the actual scheduling. I was thinking it might be cool to write something to automate the process. It's not so much about the end product though, I'm not being paid enough to write software for my employer. I've just heard everywhere that actually working on projects is the best way to learn and I'm taking this real problem as an opportunity to practice.
So my question is, where should I go from my bare bones knowledge of Python to be able to write something like this? Do I read books? Learn about fancy algorithms? Find something similar and browse its source code? Thanks!

First, you need to figure out what you want to your program to do, specifically. Programs are ways to automate processes, and you can not automate something until you know what the process is. You are trying to solve a real-world problem, the first thing you need to do is figure out how this problem is solved today (without your program).
When you try to figure this out, you should not be thinking about how to actually code it in Python, but rather what stepds need to be taken (manually) to achieve what you want. Exactly what would you do if you were doing the scheduling by hand?
Often, people find it useful to describe what a system is actually supposed to do via use cases. A use case would describe a single function, feature or process from the perspective of a user of your system. Of course, you don't need to formally write uses cases for your system, but it might help to think of what the system should be doing from a user's perspectice before thinking of the technical details to achieve this.
Once you have concrete features, processes or steps the program need to support, you can start digging into how to actually implement this in Python.

Related

What's a good resource to build my first python project?

I'm tired of books and tutorials who walk me through how to print things before I can do anything fun. I want to build simple apps or programs. Any suggestions for where to start so I can make and learn at the same time?
If you're just looking for something to do that will challenge you to start actually using Python rather than reading about it, try the Ruby Quiz. You don't have to use Ruby to create solutions.
Each quiz is a problem that can be scripted (using any language, really). Ideally it'll force you to apply the concepts you've been reading about to "real life" problems.
If you are tired of tutorials, then just start building something. Anything. If you get stuck, glance back over the tutorials, or consult the documentation. I'm a big fan of learning by doing.
A short list of options from off the top of my head:
If you're into web development, Django is a popular python web framework that is very well documented. The Blog app is a popular starting point.
Python itself is pretty well documented. If you're a complete beginner to python AND programming in general, you may want to try something less complex. Pick a random task and try to do it using python:
Read and print the ID3 tags from all your mp3 files using mutagen.
List or download your email using the python imaplib or poplib modules.
Write a zip/unzip utility using zipfile.
Don't be in too much of a hurry, and be realistic. Unless you've got a pile of programming under your belt, you won't be able to jump into a complex project after reading a few tutorials. Patience and practice will get you to the place where you can tackle really interesting projects. Impatience will merely lead to frustration.
Might i suggest pygame http://www.pygame.org/news.html ? If you want to do things with visuals, your not going to get anywhere with the default python modules unless, of course you know how to implement SDL. As stated above in the comments, the tutorials are there for a reason; although they are simple, they are meant to teach you the basics and perhaps, have you think about ideas of implementing such given tools to larger projects. Give pygame I try. You can create a window with lines and shapes in a little as ~10 lines. From there you can expand your knowledge to Object-Oriented programming(which a must for UI) and be on your way to larger projects such as AI, graphics, etc.
P.S. Check this book out http://apress.com/book/view/1590598725. Although you might not want to get into game development, it will teach you some rather useful techniques which may help your research in application development.

Once I know the basic elements and syntax of Python, what should I do?

Well, I have read several user guides and watched dozens and dozens of video tutorials on how to program with Python, and feel pretty confident about writing simple applications for it. My main point in my question is, where would I be able to learn more advanced programming knowledge about Python?
How simple of applications are you making? Have you gone through the exercises in Google's Python Class? I highly recommend going through those. If you really know what you are doing, you should breeze through them. If not, then you'll be learning some valuable skills and becoming a little more experienced in Python.
After that, it depends on what your end goals are with Python. If you don't have any goals then you should work on setting some goals and making some small applications to develop your skills in the areas that go well with those goals.
Also, a good way to learn more about Python is to try to answer the questions posted on here about Python. Even if you don't find the best answer, reading other people's answers will help you as well as the process of trying to find the answer.
You could try something like Python Cookbook or Python Challenge.
But your question is a little too vague. Why did you learn Python? What kind of problems are you looking at solving? Based on the answer to that, I can direct you to various modules like os, sys, Tkinter, etc
You have given yourself an answer:
and feel pretty confident about
writing simple applications for it
go ahead and write more complex applications!
The issue here is that you do not feel challenged, and you assume that you are done with your basic learning. Just find what to do! Simplify a process (say, file management), retrieve data from Internet (say, the last 25 twitter posts about Python), consolidate your mail clients into a single command line application, etc.
The MOST productive thing you could do (assuming you really don't have problems of your own), is to find an open source Python project (say, Matplotlib) and become a contributor. You will quickly realize that Python is beautiful, but it is a beast nevertheless.
If you still feel unchallenged, contact me and I will send you a ton of stuff to code which, believe me, is not easy.
Good luck!
my favorite way in learning python is ( learning through projects ).
put yourself a goal , like a software for example ( 6 years ago when i started to learn python i picked a messenger . so i had to read more about sockets, network programming , and interfaces libraries ) . start with it , look for examples and resources to learn more . then do it.
the key is NOT TO GIVE UP and keep trying and searching until you make it .
. this can be fastest and the most efficient way in learning any programming language .
good luck ;)
If you like puzzles, you might check out Project Euler. It has a variety of interesting puzzles (some easy, some much harder) that take some logic and programming to solve. (Often you have to find a clever way to solve them, since brute-force methods will take forever.)
If you're at all interested in web development you might look into Django. It's a very nice web framework that lets you use Python; it's mature and quite powerful.
I also second Arrieta's suggestion of finding an open-source Python project and looking into getting involved. You can find a list of such projects on GitHub, freshmeat, and SourceForge, among others.

General questions regarding Python language

I'm a newbie to programming and I've decided to start with Python. Just curious though, is it enough/recommended to learn Python from online tutorials or from books? I want to go further than simple "Hello World!" programs. I'm not sure if books will actually teach you how to make more advanced programs.
One example is Exif-py. How do you even start programming a program like this? Do you just sit down and start writing the code, or do you have to search for APIs or anything? I went through the code briefly and it all looked alien to me.
I'm not really sure how to express my questions into words, so do check back because I'll edit my question if the right words come to me.
Well, I learnt all my Python from online sources (not just tutorials, but reference documentation, blog posts and other texts). It's certainly possible, although some people prefer the "guided" way a book teaches you, particularly people new to programming (at that point I had already been programming for years).
To create a program such as Exif.py, you would first have to know what you must do in broad terms BEFORE starting to program. You would study the EXIF format, then figure out how that is put into the image files, then you would have to formulate that in terms of the language you're using (in this case, Python). This usually requires that you're already familiar with it, otherwise it'll be a fairly slow process.
I'd suggest starting with simpler programs to begin with, or maybe follow a book such as Dive Into Python (free online), seeing as you're new to programming, and need to not only learn the language, but to think like a programmer.
The tutorials are there to teach you the language syntax and the standard library, not really on how to solve a particular programming problem. Think of what you learn there as your toolbox.
I think I understand what you are saying. You want to break above and beyond the simple applications and write your own stuff, right? Well, first you need to figure out what it is you want to make. Then comes the hard part; how are you going to make it? I'd suggest starting by trying to break it down into a number of small simple problems instead of tackling it as one large problem.
If you are trying to find examples of larger projects, I'd suggest looking at the Python Cheeseshop (package index) and download a few packages you've heard of to see how they did it. Also, people often post handy pieces of code on their personal blogs and that shows up on PlanetPython.
If stuff like recursion, modules, classes, iteration, exceptions, dictionaries, are indeed new to you, I suggest How to Think Like a Computer Scientist in Python (lovingly abbreviated as ThinkCSPy in the community ;-).
It is a bit outdated - for best results, use Python 2.6 or lower, but then again 3.0 is not that different.
EDIT: If ThinkCSPy has little to teach you, try Dive Into Python. It's advanced and pretty "real-world", but step-by-step.
If by 'newbie to programming' you mean that you just started it last week or something along the lines, then maybe you might want to give the MIT OpenCourseWare Introduction to Computer Science videos (and homework!) a bit of your time.
The opencourse covers the syntax of the Python language, some helpful hints and general do's and don'ts that apply to any programming paradigm.
Though, if by 'newbie to programming', that you already know the basic concepts you need to start writing basic programs (like adding, subtracting, multiplying, logical operations, functions etc).
If so, Project Euler is particularly good for exercising that cranial muscle in problem solving via programming, though most of the problems on the site require you at also have knowledge of mathematics (and if you don't, at least know how to google).
Just remember, if you get stuck on anything don't get put down! It's all part of learning! If you're really stuck, search SO!
There are a few very good online resources:
The Python Tutorial.
Dive Into Python. Python from novice to pro.
Code Like a Pythonista: Idiomatic Python
Another list of resources: Essential Python Reading List.
Most Python books I've seen so far are "not that good" - but that depends
on your background / prior knowledge about Python and programming.
You study the EXIF format, study the GIF/JPEG format, open the binary file, scan it and get the data out.

How to reverse engineer a program which has no documentation [closed]

Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 7 years ago.
Improve this question
I have a source of python program which doesn't have any documentation or comments.
I did tried twice to understand it but most of the times I am losing my track, because there are many files.
What should be the steps to understand that program fully and quickly.
Michael Feathers' "Working Effectively with Legacy Code" is a superb starting point for such endeavors -- not particularly language-dependent (his examples are in several non-python languages, but the techniques and mindset DO extend pretty well to Python and just about any other language).
The key focus is, that you want to understand the code for a reason -- modifying it and/or porting it. So, instrumenting the legacy code -- with batteries and scaffolding of tests and tracing/logging -- is the crucial path on the long, hard slog to understanding and modifying safely and responsibly.
Feathers suggests heuristics and techniques for where to focus your efforts and how to get started when the code is a total mess (hence "legacy") - no docs, or misleading docs (describing something quite different, maybe in subtle ways, from what the code actually DOES), no tests, an untestable-without-refactoring tangle of spaghetti dependencies. This may seem an extreme case but anybody who's spent a long-ish career in programming knows it's actually more common than anyone would like;-).
In past I have used 'Python call graph' to understand the source structure
Use a debugger e.g. pdb to wak thru
the code.
Try to read code again after one day
break, that also helps
I would recommend to generate some documentation with epydoc http://epydoc.sourceforge.net/ . For sure, if no docstring exists, the result will be poor but it will give you at least one view of your application and you'lle be able to navigate in the classes more easily.
Then you can try to document by yourself when you understand something new and then regenerate the docs again. It is never too late to start something.
I hope it helps
You are lucky it's in Python which is easy to read. But it is of course possible to write tricky hard to understand code in Python as well.
The steps are:
Run the software and learn to use it, and understand it's features at least a little bit.
Read though the tests, if any.
Read through the code.
When you encounter code you don't understand, put a debug break there, and step through the code, looking at what it does.
If there aren't any tests, or the test coverage is low, write tests to increase the test coverage. It's a good way to learn the system.
Repeat until you feel you have a vague grip on the code. A vague grip is all you need if you are going to manage the code. You'll get a good grip once you start actually working with the code. For a big system that can take years, so don't try to understand it all first.
There are tools that can help you. As Stephen C says, an IDE is a good idea. I'll explain why:
Many editors analyses the code. This typically gives you code completion, but more importantly in this case, it makes it possible to just just ctrl-click on a variable to see where it comes from. This really speeds things up when you want to understand otehr peoples code.
Also, you need to learn a debugger. You will, in tricky parts of the code, have to step through them in a debugger to see what the code actually do. Pythons pdb works, but many IDE's have integrated debuggers, which make debugging easier.
That's it. Good luck.
I have had to do a lot of this in my job. What works for me may be different to what works for you, but I'll share my experience.
I start by trying to identify the data structures being used and draw diagrams showing the relationships between them. Not necessarily something formal like UML, but a sketch on paper which you understand which allows you to see the overall structure of the data being manipulated by the program. Only once I have some view of the data structures being used do I start to try to understand how the data is being manipulated.
Secondly, for a large body of software, sometimes you need to just attack bite sized pieces at first. You won't get an overall understanding straight away, but if you understand small parts in detail and keep chipping away, eventually all the pieces fall together.
I combine these two approaches, switching between them when I am getting overly frustrated or bored. Regular walks around the block are recommended :) I find this gets me good results in the end.
Good luck!
pyreverse from Logilab and PyNSource from Andy Bulka are helpful too for UML diagram generation.
I'd start with a good python IDE. See the answers for this question.
Enterprise Architect by Sparx Systems is very good at processing a source directory and generating class diagrams. It is not free, but very reasonably priced for what you get. (I am not associated with this company in any way, I've just been a satisfied user of their product for several years.)

I need a really good reason to use Python

I have been trying to make a case for using Python at my work. We use C# and ASP.NET for basically all of our development. 80% or more of our projects are web applications. It seems natural that we would look at some of the nice dynamic web languages (Ruby, Python, etc), and with things like IronRuby and IronPython, I started seriously investigating.
I love Python. It's a beautiful, expressive language. It's a joy to code in, for sure. The multitude of python modules and frameworks make it very appealing. Problem is, I cannot think of any specific problems, any specific hurdles that would require a language like Python. ASP.NET gives us RAD, it gives us a full-featured framework and all that good stuff. Also, we all already know C# and have lots of projects in C#, learning a new language just because doesn't quite work.
Can you guys help me think of something to finally convince my boss to really learn Python and start using it on projects?
Edit: I know that no problem requires only one language, I just meant, are there any specific problems in which dynamic languages excel over static languages.
Edit again: Let me also mention that my boss prompted ME to investigate this. He has put aside hours to research these languages, find a good one, learn it, and then figure out how we can use it. I'm at the last step here, I do not need a lecture on why I should consider my motivation for changing something my company does because they do it for a reason.
"Can you guys help me think of something to finally convince my boss to really learn Python and start using it on projects?"
Nope.
Nothing succeeds like success. Use Python. Be successful. Make people jealous.
When asked why you're successful, you can talk about Python. Not before.
Choose projects wisely: things where a dynamic language has significant advantages. Things where the requirements are not nailed down in detail. Things like data transformations, log-file scraping, and super-sophisticated replacements for BAT files.
Use Python to get started doing something useful while everyone else is standing around trying to get enough business and domain information to launch a project to develop a complicated MVC design.
Edit: Some Python to the Rescue stories.
Exploratory Programming
Tooling to build test cases
What's Central Here?
Control-Break Reporting
One More Cool Thing About Python Is...
In Praise of Serialization
And that's just me.
Edit: "boss prompted ME to investigate", "figure out how we can use it" changes everything.
The "finally convince my boss to really learn Python" is misleading. You aren't swimming upstream. See How Do I Make the Business Case for Python for the "convince my boss" problem. The edit says you're past this phase.
Dynamic languages offer flexibility. Exploit that. My two sets of examples above are two areas where flexibility matters.
Requirements aren't totally nailed down. With a dynamic language, you can get started. Rework won't be a deal-breaker. With Java (and C++ and C#) you are reluctant to tackle devastating design changes because it's hard to break everything and get it to compile and work again. In Python, devastating changes aren't as expensive.
Design is in flux because you can't pick components. You can write Wrappers and Facades very easily in Python. It's a scripting language. And, Python modules compose into larger aggregates very simply.
Coding is in flux because requirements and design keep changing. It's scripted -- not compiled. You just make a change to the code and you're off and running. Testing is easier because the work cycle is shorter. It isn't code-compile-build-test it's code-test.
Testing is in flux because the requirements keep changing. Same as above. The work cycle is shorter and faster.
Almost no problem requires a specific programming language, that's just not how things work.
The easiest way to get a new language into an environment like yours is to start a new work project in your own time in the new language. Make it do something you need doing, and write it on your own time. Use it yourself, and other people will probably notice it. They then say "Can you send me that program?" and boom, they're using your new language.
If you really want to something, I would probably write a site in Django, simply because its admin interface blows everyone away.
The main point to remember is that if you start using python, that's one more thing everyone else has to learn, and it's another bullet point that will need to be on every prospective employee's resume. That can get expensive, and management won't like it.
Sneaking a language in is often done by automating tedious manual tasks (especially dynamic/scripting languages like Python/Ruby etc). Set it up so something like deploying builds, or shuffling backups, or whatever is done with Python.
Then casually slip in how easy it was to do, and try to spread some of the enthusiasm around.
Acceptance and awareness should slowly grow from that, and before you know it, management is seriously considering Python for a new project.
Can you guys help me think of
something to finally convince my boss
to really learn Python and start using
it on projects?
Unfortunately, the answer is no. As Harley said, no problem is going to require a specific language. The approach Harley suggested is also a good one. Learn on your time, build an useful app on your time, and maybe, just maybe, someone at your work will want to use it, like it, love it, then want to learn more about it.
Another approach you could take is to get a better understanding of why your company uses .Net (therefore, Windows Server, and probably SQL server) for nearly all development. Once you have a good understanding of why they aren't open to other languages, then you have some fire power to build a business case for the "why not?".
Why pay licensing costs when you have tools that can accomplish the same things? There are free alternatives out there, like Python, that run on free servers.
Why not give your team the chance to grow their professional tool-belt? This is my opinion, but a good developer is a developer that isn't afraid to learn new ways of doing the same thing they've done before.
But, in the end, I wouldn't get your hopes up. Bottom line, it costs money to introduce a new language/environment into an IT shop. Whether it's software, training, or employee rollover, there is a business reason behind utilizing a single language for a company, and sticking to it.
I'm in the exact scenario you're in. I work in a .Net shop, and that's not going to change any time soon. I get by, by working on my own projects in my "free" time. I enjoy it, and it makes for a good balance.
Hope this helps.
Take a step back, and look at your approach. "I know what I want the answer to be, but I can't find any evidence to support it."
Despite the fact that Python is my current first choice language, I am afraid I find myself on the side of your boss! Sorry.
I think you should open your mind and consider all the options from the stance of your organisation's best interest, and see if you don't come to a different conclusion about the best language.
There are many factors in the choice of language, and how pretty it is is a fairly minor one. The availability of staff is a key one. The cost of retraining, availability of the libraries and meta-tools, performance, etc. etc.
Once you have taken into consideration all the different factors (and not just "Oooh! It'd be fun!") and made a balanced assessment (rather than a predetermined answer), you may find that your boss is more willing to listen.
p.s. The suggestion to secretly use Python for work code, and leaving the company with a terrible code debt in a language they are not prepared for seems very unprofessional to me.
The best leverage you're likely going to have is tools and libraries; as others have pointed out, no language is required to solve any particular program. So let's look at Things You Can Leverage Using Python:
Google App Engine
SciPy
pywinauto
django
Those are off the top of my head; finding what's applicable to your team and your company is left as an exercise for the questioner :)
Well, here's a view of why Python programmers make better Java programmers; the concepts are much the same as for your situation.
Essentially, people who learn a language because they want to show that they enjoy programming, like to learn new things, and are more likely to think outside the box.
...if a company chooses to write
its software in a comparatively
esoteric language, they'll be able to
hire better programmers, because
they'll attract only those who cared
enough to learn it. And for
programmers the paradox is even more
pronounced: the language to learn, if
you want to get a good job, is a
language that people don't learn
merely to get a job.
Not only that, but Python enforces "good looking" code and you don't have to do the whole code/compile routine. With IronPython, you can simply code in Python and use it as is; just another .NET tool.
Python got a good start in the Java world as Jython for unit testing. In fact many Java people started using it first that way. Its dynamic scripting nature makes it a great fit for unit tests. Just yesterday I was wishing I could use it or something like it for the unit tests I was writing for a VB.Net project. I'd have to say that it isn't so much about the individual language IronRuby or IronPython as it is about the style of development that they enable. You can write static language like code in either but you don't fully reap the benefits until you can start to think dynamically. Once you grasp those concepts you'll start to slowly change the way you code and your projects will require less classes and less code to implement. Testing, particularly unit tests will become a must since you give up the warm blanket known as a compiler with type safety checks for other efficiencies.
The language is almost never the key to success. Good programmers can be successful in a variety of languages, and you'll find successful projects in almost any language. You won't find the failures that much because those projects just go away never to be heard of again. If you're looking for a new language because you don't have good programmers, even the best language in the world isn't going to help.
And, you haven't said anything about the sort of work you're doing. Python might be a good choice because it has well-supported and widely-used libraries that are critical for you. On the other hand, C# might have better support for the stuff that you want to do. A tool outside of context has no intrinsic merit. You might love screwdrivers, but that doesn't help you row a boat.
If you want to use Python, or any other language, just because you like it, be honest with yourself and those around you. It looks like you've made a decision to switch, don't know why you are switching, and now need to rationalize it with reasons that had nothing to do with your desire to switch. If you had a good reason, you wouldn't be asking here :)
That's not entirely a bad thing, though. Programming is a human enterprise. If the programmers (at whatever level) insanely love a particular language, no matter how stupid the reason, they are probably going to produce more. It's just not a technological solution though.
Good luck, :)
I am pretty sure (100%) that you don't need to use Python for MS Windows at least.
In cases of other platforms you can use any language you like.

Categories

Resources