Simple D3 examples to try

I learn by looking at examples and then trying to modify them to do what I want. I've started creating little gists to record how use different features of d3. In case they help others, here is a start. They can all be run in bl.ocks

Processing CSV strings and files and grouping with nest:

• https://gist.github.com/3053667 - processing csv string 
• https://gist.github.com/3053705 - processing csv file 
• https://gist.github.com/3096857 - nesting/grouping to two levels

Drawing Axes:

• https://gist.github.com/3053419 - simplest possible
• https://gist.github.com/3059392 - date axis
• https://gist.github.com/3061203 - prettified, angled date labels and uses extent
• https://gist.github.com/3098488 - rescale an axis using a transition