Webucator's Blog

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Still using Python 2? It is time to upgrade.

Most Python programmers agree that Python 3, which has been available since 2008, is a big improvement over Python 2, but many (most?) Python developers are still using Python 2. The main reasons for this, according to a 2014 survey, are:

  1. They are relying on Python 2 libraries that have not been ported to Python 3.
  2. They have a large Python 2 code base, which would be time consuming and difficult to rewrite.
  3. They see no real advantage to switching.

But there are now clear signs that Python 2, which one developer argues we should start calling “Legacy Python”, is on it’s way out. Continue Reading »

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How to Change the Home Directory for IPython Notebook

You used to be able to change the default (i.e., Home) directory in┬áIPython Notebook on Windows by setting the┬ác.NotebookApp.notebook_dir property in┬áipython_notebook_config.py, but that doesn’t appear to be working anymore. The workaround I found was to create a batch file and pin it to the Windows taskbar. Here’s how: Continue Reading »

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Appending to Long Strings in Python

Be careful when repeatedly appending to a string in Python. Because strings are immutable, each time you change one, a new object is created. The code below is very intuitive:

r=1000000

s = ''
for i in range(r):
    s += str(i)

But it doesn’t perform too well.

A better approach is to create and append to a list and then convert it to a string using ''.join(l), like this: Continue Reading »

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Markdown ATX Headers Require a Space after Hashes

I just upgraded to Anaconda 2.4, which includes Python 3.5. To update, just run the following code:

conda update conda
conda install anaconda=2.4 

Almost everything seems to have gone smoothly. The exception was that all the markdown headers in my IPython notebooks lost their formatting. They started showing up like this:
Broken Markdown Headers Continue Reading »