Language - Python: Difference between revisions

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[[Category:Language]]
[[Category:Language]]
[[File:icon-Python.png|64x64px|link=|alt=Python]] Python is an object oriented programming language developed by the [http://www.python.org/psf/summary/ Python Software Foundation], is powerful and easy to learn.
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__TOC__
We provide support for Python in all major operating systems. We also provide instructions on how to get your project started in a number of common development environments. Select your operating system and preferred development environment below, and follow the instructions to get your project running with Phidgets.


==Introduction==
If you do not know which development environment you want to use, or your development environment of choice is not listed, we recommend starting with command line or terminal as the simplest path to getting your code running.


{{LanguageSupport|Python|the complete Phidget API, including events|all Phidget devices.|Windows, OS X and Linux. We provide instructions on how to set up your environment for [[#Command line | command line]], [[#IDLE | IDLE]], and [[#Eclipse with PyDev | Eclipse with PyDev]]|
Once you have set up your development environment to run with Phidgets, we recommend you follow our guide on [[Phidget Programming Basics]]. The guide will showcase the fundamentals of programming with Phidgets, with examples in Python.


Only Python 2.5 or higher is supported.}}
==Choose Your Development Environment:==


==Quick Downloads==
{{Language_-_Python_Dev_Environment_Table}}


{{QuickDownloads|Python|
== Quick Downloads ==
{{APIQuickDownloads|http://www.phidgets.com/documentation/PythonDoc.zip}}|
{{ExampleQuickDownloads|http://www.phidgets.com/downloads/examples/Python_2.1.8.20120131.zip|}}|
{{ExtraLibraryQuickDownloads|http://www.phidgets.com/downloads/libraries/PhidgetsPython_2.1.8.20120131.zip|Python|}}
{{WindowsQuickDownloads}}
{{MacQuickDownloads}}
{{LinuxQuickDownloads}}
}}


==Getting started with Python==
If you already know what you're doing and just need the files, you can find them all below.


If you are new to writing code for Phidgets, we recommend starting by running, then modifying existing examples. This will allow you to:
=== Python Module ===
{{ExampleCodeReasons}}
* [{{SERVER}}/downloads/phidget22/libraries/any/Phidget22Python.zip Phidget Python module]


Instructions are divided up by operating system. Choose:
=== Documentation ===
*[[#Windows(2000/XP/Vista/7)|Windows 2000 / XP / Vista / 7]]
*[[#OS X |OS X]]
*[[#Linux | Linux]] (including PhidgetSBC)


==Windows(2000/XP/Vista/7)==
*{{Phidget22API}}  (select Python from the drop-down menu)


===Description of Library===
=== Example Code ===
Python programs on Windows depend on the following. The installers in the [[#Libraries and Drivers | Quick Downloads]] section put only the {{Code|phidget21.dll}} into your system. You will need to manually put the Phidget Python Module into your system.
* <b>{{Code|phidget21.dll}}</b> contains the actual Phidget library, which is used at run-time.  By default, it is placed in {{Code|C:\Windows\System32}}.
* <b>{{Code|Phidget Python Module}}</b> is the Phidget library for Python.
* <b>{{Code|setup.py}}</b> is used to install the Phidget module into the standard location for third party Python modules. On typical Python environments, this setup will install the Phidget Python module in the {{Code|site-packages}} directory.


If you do not want to use our installer, you can download the [http://www.phidgets.com/downloads/libraries/Phidget21-windevel_2.1.8.20111220.zip {{Code|phidget21.dll}}].
*{{SampleCode|Python|Python Examples}}


 
===Libraries===
The first thing you will have to do is to [[#Installing the Phidget Python Module |install the {{Code|Phidget Python Module}}]].
{{AllQuickDownloads}}
Afterwards, Running the examples and writing your own code can be fairly compiler-specific, so we include instructions for each environment below.
 
===Installing the Phidget Python Module===
 
Please start by downloading [http://www.phidgets.com/downloads/libraries/PhidgetsPython_2.1.8.20120131.zip Phidget Python Module]. After extracting the file, open up a command line terminal, traverse to the directory containing {{Code|setup.py}} and enter the following to install the Phidget Python module into the Python environment.
 
<div class="source">
<syntaxhighlight lang=bash>
python setup.py install
</syntaxhighlight>
</div>
 
===Command Line===
====Use Our Examples====
Please ensure that the Phidget Python Module is [[#Installing the Phidget Python Module | installed]] onto your system.
 
Next, download the [http://www.phidgets.com/downloads/examples/Python_2.1.8.20120131.zip examples] and unpack them into a folder.  While these examples were written in Python 3.0, they are also compatible with Python 2.5(with a [[#All Operating Systems: The examples produces an error while running in a Python 2.5 environment. | minor modification]]). If you aren't sure what the software example for your device is called, check the software object listed in the [[Device List | Getting Started guide for your device]].
 
Now, open up a command line prompt and navigate to the directory of the example folder.
 
Next, enter the following to run the example:
 
<div class="source">
<syntaxhighlight lang=bash>
python example.py
</syntaxhighlight>
</div>
 
Once you have the Python examples running, we have a [[#Follow the Examples|teaching]] section below to help you follow them.
 
====Write Your Own Code====
 
When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your environment to properly link the Phidgets Python libraries. Please see the [[#Use Our Examples| Use Our Examples ]] section for instructions.
 
Then, in your code, you will need to reference to the Phidget Python library.
 
<div class="source">
<syntaxhighlight lang=python>
from Phidgets.PhidgetException import *
from Phidgets.Events.Events import *
</syntaxhighlight>
</div>
 
Then, you will also have to add a reference to your particular Phidget.  For example, you would include the following line for a PhidgetInterfaceKit:
<div class="source">
<syntaxhighlight lang=python>
from Phidgets.Devices.InterfaceKit import *
</syntaxhighlight>
</div>
 
Please see the [http://www.phidgets.com/downloads/examples/Python_2.1.8.20120131.zip examples] on how to add a reference to your particular Phidget.
 
The project now has access to the Phidget function calls and you are ready to begin coding.
 
The same [[#Follow the Examples|teaching ]] section which describes the examples also has further resources for programming your Phidget.
 
===IDLE===
 
====Use Our Examples====
 
Please start by downloading [http://www.phidgets.com/downloads/libraries/PhidgetsPython_2.1.8.20120131.zip Phidget Python Module]. After extracting the file, open up a command line terminal, traverse to the directory containing {{Code|setup.py}} and enter the following to install the Phidget Python module into the Python environment.
 
<div class="source">
<syntaxhighlight lang=bash>
python setup.py install
</syntaxhighlight>
</div>
 
Next, download the [http://www.phidgets.com/downloads/examples/Python_2.1.8.20120131.zip examples] and unpack them into a folder.  While these examples were written in Python 3.0, they are also compatible with Python 2.5(with a [[#All Operating Systems: The examples produces an error while running in a Python 2.5 environment. | minor modification]]). If you aren't sure what the software example for your device is called, check the software object listed in the [[Device List | Getting Started guide for your device]]. Now, open the example in the IDLE editor.
 
The only thing left to do is to run the examples! Click on Run &rarr; Run Module.
 
[[File:Python IDLE Run.PNG|link=|alt=Run?]]
 
Once you have the Python examples running, we have a [[#Follow the Examples|teaching]] section below to help you follow them.
 
====Write Your Own Code====
 
When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your environment to properly link the Phidget Python library. Please see the [[#Use Our Examples 2| Use Our Examples ]] section for instructions.
 
Then, in your code, you will need to reference to the Phidget Python library.
 
<div class="source">
<syntaxhighlight lang=python>
from Phidgets.PhidgetException import *
from Phidgets.Events.Events import *
</syntaxhighlight>
</div>
 
Then, you will also have to add a reference to your particular Phidget.  For example, you would include the following line for a PhidgetInterfaceKit:
<div class="source">
<syntaxhighlight lang=python>
from Phidgets.Devices.InterfaceKit import *
</syntaxhighlight>
</div>
 
Please see the [http://www.phidgets.com/downloads/examples/Python_2.1.8.20120131.zip examples] on how to add a reference to your particular Phidget.
 
The project now has access to the Phidget function calls and you are ready to begin coding.
 
The same [[#Follow the Examples|teaching ]] section which describes the examples also has further resources for programming your Phidget.
 
===Eclipse with PyDev===
 
====Use Our Examples====
 
1. Please start by downloading [http://www.phidgets.com/downloads/libraries/PhidgetsPython_2.1.8.20120131.zip Phidget Python Module]. After extracting the file, open up a command line terminal, traverse to the directory containing {{Code|setup.py}} and enter the following to install the Phidget Python module into the Python environment.
 
<div class="source">
<syntaxhighlight lang=bash>
python setup.py install
</syntaxhighlight>
</div>
 
2. Next, download the [http://www.phidgets.com/downloads/examples/Python_2.1.8.20120131.zip examples] and unpack them into a folder.  While these examples were written in Python 3.0, they are also compatible with Python 2.5(with a [[#All Operating Systems: The examples produces an error while running in a Python 2.5 environment. | minor modification]]). If you aren't sure what the software example for your device is called, check the software object listed in the [[Device List | Getting Started guide for your device]]. You will need this example source code to be imported into your project later on.
 
3. Next, a new project will need to be created. Generate a new PyDev project with a descriptive name such as PhidgetTest.
 
[[File:Python PyDev New Project.PNG|link=|alt=New Project]]
 
4. To import the example program into your project, right click the Project and select {{Code|Import}}.
 
[[File:Python PyDev Import File 1.PNG|link=|alt=Import File]]
 
5. On the next screen, select {{Code|File System}} and proceed to the next screen.
 
[[File:Python PyDev Import File 2.PNG|link=|alt=Import File]]
 
6. Browse to the directory where you extracted the examples into, and select the example you wish to open.
 
[[File:Python PyDev Import File 3.PNG|link=|alt=Import File]]
 
7. The only thing left to do is to run the examples! Click on Run &rarr; Run.
 
[[File:Python PyDev Run.PNG|link=|alt=Run?]]
 
Once you have the Python examples running, we have a [[#Follow the Examples|teaching]] section below to help you follow them.
 
====Write Your Own Code====
 
When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your environment to properly link the Phidget Python library. Please see the [[#Use Our Examples 3 | Use Our Examples ]] section for instructions.
 
Then, in your code, you will need to include a reference to the Phidget Python library.
 
<div class="source">
<syntaxhighlight lang=python>
from Phidgets.PhidgetException import *
from Phidgets.Events.Events import *
</syntaxhighlight>
</div>
 
You will also have to add a reference to your particular Phidget.  For example, you would include the following line for a PhidgetInterfaceKit:
<div class="source">
<syntaxhighlight lang=python>
from Phidgets.Devices.InterfaceKit import *
</syntaxhighlight>
</div>
 
Please see the [http://www.phidgets.com/downloads/examples/Python_2.1.8.20120131.zip examples] on how to add a reference to your particular Phidget.
 
The project now has access to the Phidget function calls and you are ready to begin coding.
 
The same [[#Follow the Examples|teaching ]] section which describes the examples also has further resources for programming your Phidget.
 
==OS X==
 
Python has excellent support on OS X.
 
The first step in using Python on Mac is to install the Phidget libraries.  Compile and install them as explained on the [[Device List|getting started guide for your device]].  Then, the [[OS - OS X]] page also describes the different Phidget files, their installed locations, and their roles....
 
==Linux==
 
Python has support on Linux. 
 
The first step in using Python on Linux is to install the Phidget libraries.  Compile and install them as explained on the main [[OS - Linux | Linux page]].  That Linux page also describes the different Phidget files, their installed locations, and their roles.
 
==Follow the Examples==
 
By following the instructions for your operating system and compiler above, you probably now have a working example and want to understand it better so you can change it to do what you want.  This teaching section has resources for you to learn from the examples and write your own.
 
Next, comes our API information.  These resources outline the Python Phidget functions:
 
{{UsingAPhidgetInCodeGeneral|both of which are available in Python|[http://www.phidgets.com/documentation/PythonDoc.zip Python API]}}
 
===Example Flow===
 
{{ExamplePseudocode|In Python, you can name these '''event''' functions whatever you like.  You will then pass them as function pointers to the Phidget library below in the Main Code section.  This hooks them into the actual events when they occur. <br>
In the example code, the event functions common to all Phidgets are called things like '''AttachHandler()''' and '''DetachHandler()''', etc.<br><br>
Some event functions will be specific to each device, like when a tag is read on an RFID board, or when a sensor value changes on an Interface Kit.
Other functions are given in the examples to show you more detail on using your Phidget.  For example, '''DeviceInitialize()''' will show what needs to be set up for your Phidget before using it.
|Creating a Phidget software object in Python is specific to the Phidget.  For a Phidget Spatial, for example, this would involve creating a {{Code|Spatial}} object.  The examples show how to do this and other API functions.<br><br>
The object provides device specific methods and properties which are available from the API for your specific Phidget.|
[http://www.phidgets.com/documentation/PythonDoc.zip Python API]}}
 
==Code Snippets==
 
==Common Problems and Solutions/Workarounds==
 
==={{ProblemSolution|OS X|My application hangs when using multiple devices in a single Python application.}}===
 
A call to {{Code|open}} may hang indefinitely if multiple devices are being programmed in a single Python application. To circumvent this, allow the application to delay a short period between {{Code|open}} calls. For most environments, a 1.25 millisecond delay is enough. For example:
<div class="source">
<syntaxhighlight lang=python>
import time
...
interface_kit.openPhidget(94695)
time.sleep(0.00125)
rfid.openPhidget(33502)
</syntaxhighlight>
</div>
 
 
==={{ProblemSolution|All Operating Systems|The examples produces an error while running in a Python 2.5 environment.}}===
 
Running the examples produces an error similar to the following:
<div class="source">
<syntaxhighlight lang=python>
InterfaceKit-simple.py:33: Warning: 'as' will become a reserved keyword in Python 2.6
  File "InterfaceKit-simple.py", line 33
    except RuntimeError as e:
SyntaxError: invalid syntax
</syntaxhighlight>
</div>
 
To run the example code in Python 2.5, all the lines containing:
<div class="source">
<syntaxhighlight lang=python>
except RuntimeError as e:
</syntaxhighlight>
</div>
will need to be replaced with:
<div class="source">
<syntaxhighlight lang=python>
except Runtime, e:
</syntaxhighlight>
</div>

Revision as of 22:14, 28 February 2019


We provide support for Python in all major operating systems. We also provide instructions on how to get your project started in a number of common development environments. Select your operating system and preferred development environment below, and follow the instructions to get your project running with Phidgets.

If you do not know which development environment you want to use, or your development environment of choice is not listed, we recommend starting with command line or terminal as the simplest path to getting your code running.

Once you have set up your development environment to run with Phidgets, we recommend you follow our guide on Phidget Programming Basics. The guide will showcase the fundamentals of programming with Phidgets, with examples in Python.

Choose Your Development Environment:

Python Development Environments
OS - Windows Windows

PY PCH WIN.png PY PCH WIN on.png

PY CL WIN.png PY CL WIN on.png

PY LI WIN.png PY LI WIN on.png

PY VS WIN.png PY VS WIN on.png

PY IDLE WIN.png PY IDLE WIN on.png

OS - macOS macOS

PY CL MAC.png PY CL MAC on.png

OS - Linux Linux

PY CL LNX.png PY CL LNX on.png

OS - Linux Phidget SBC Linux

PY CL SBC.png PY CL SBC on.png

Quick Downloads

If you already know what you're doing and just need the files, you can find them all below.

Python Module

Documentation

Example Code

Libraries

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