Python Editor: Programmer's Notepad 2

Intro to PN2

Programmer's Notepad is a decent, free, and open-source editor for MS Windows recognizes (and can highlight syntax for) several different programming languages from Assembly to XML, and many others in between, including, of course, Python.

Besides syntax highlighting, PN2 has some features that are particularly useful to coders. It allows you to create Tools, such as a Run Python menu item that will call python.exe to execute your Python code without having to switch over to another window running a Python shell, such as iPython. It will then display resulting output in an output window.

Another very convenient feature is that it will group sections of code and make them collapsible so that you can hide blocks of code to make the a page or window more readable.

One feature missing from PN2 is that although it will highlight syntax, it does not (yet) automatically indent, for example, the line after a for loop. However, it will maintain the indentation of the current line, so you won't have to constantly tab within a single code block.

Installing and Configuring PN2

You can download a copy here from the SourceForge website. It should install in the directory C:\Program Files\Programmers Notepad. PN2 uses what are called schemes to define the way it recognizes languages and file types. There is a pull-down menu on the top toolbar where you can choose a scheme, but it will automatically choose the Python scheme for you if you open a file with a .py extension.

To turn on view options such as line numbers and wordwrap, go to Tools->Options. This dialog box is where you can configure all of the default settings. Click on Defaults for line numbers and other options. This dialog box is also where we can add tools, such as a Run Python tool (more on this later).

To see the effects of syntax highlighting, first choose Python from the pull-down menu on the toolbar. Then as you enter Python code, PN2 will color-code keywords, function names, and the like, as well as grouping contiguous code blocks. You can see these features in action if you enter code for iterating the logistic map:


def printIterates(OneDMap, initialConditions, nIterates):
    x=initialConditions
    for i in range(nIterates):
        x=OneDMap(x)
        print i, x

def LogisticMap(x):
    return 4.0 * x * (1.0 - x)

printIterates(LogisticMap, 0.3, 10)

Save this as LogisticMap.py. Your editor window should look similar to the one below:

We can add more functionality to our editor by adding a tool that lets us execute Python code directly in the editor, without having to switch to another Python shell window. To add a new tool, click on the Tools->Add Tools.... This will bring up the Options dialog box. Under the Scheme pull-down menu, make sure Python is selected since we only want this tool to be active for the Python scheme. Then click on the Add button. There are four fields we will need to fill in and an optional fifth field for a shortcut key.

Under Name type in the name of the new tool
Under Command enter the full path of python.exe (This should be the same as in the figure below unless the default installation path was not used)
Under Folder enter %d to specify the current path of the file to be executed
Under Parameters enter %f to specify the name of the current file
Optional: Under Shortcut enter the shortcut keys you would like to use to invoke the Run Python tool (here, Control+1 is used as an example)

Click OK once these fields are entered. This will place a Run Python item under the Tools menu, but it will only appear when you are using the Python scheme.

In order to run the tool on our LogisticMap.py code, first make sure the Output window is visible. If it is not already visible, go to View->Output. Then go to Tools->Run Python. You should then see numbers generated from iterating the logistic map in the Output window:

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