With the xpPython modifier, you can arrange for Python code to be executed when a particle is within the modifier's field of effect.

You have access to the particle data, which enables you to change the data in any way you like.

Object Properties

xpPython Object tab menu.

Enabled

Checking this box enables the xpPython modifier.

Mode

Set at Independent by default.

You can change this to Action-Controlled.

Independent Mode

In this mode, particles will be affected if they come into the field of effect of the modifier.

Action-Controlled Mode

When in the Action-Controlled Mode setting, the modifier will only act on a particle when told to do so by an action.

Visible in Editor

Enabled, by default, click to make the modifier invisible in the editor.

Script