Unreal Python Recipe Book
  • About
  • Getting Started
  • Dev Conveniences
    • Python Command Line
    • Modifier Keys (alt, ctrl shift)
    • Convenience Modules
    • Abstraction Layer
  • Assets
    • Loading Assets
    • New Asset Instances
    • Getting the Default Object
    • Get / Set Editor Properties
    • Calling BP Graph Functions
    • Asset Path ↔ File Path
    • Python Module Example
  • Actors
    • Get Asset from Actor
      • [c++] Get Asset List For Actor
    • Spawning Actors
    • Get All Actors in 3D Level
    • Walking The Actor Hierarchy
    • Walking Components
    • On Selection Changed Callback
    • Python Module Example
  • Metadata
    • Epic Documentation
    • [c++] Registering Metadata Tags
    • Setting Metadata
    • Getting Metadata
    • Find Assets By Metadata
    • Python Module Example
  • Calling Python From Blueprint
    • The Execute Python Script Node
    • Blueprint Function Libraries
      • Python Module Example
      • Making BP Function Libraries Safer
    • Subsystems (Don't Use)
  • Editor Menus
    • Discovering Menus to Extend
    • Getting a Reference to a Menu
    • Adding a Drop Down Menu
    • Python Menu Class
      • Insert Position
      • Menu Icons
      • Toggled Menu Entries
      • Editor Utility Widget Launcher
    • Python Module Example
  • Startup & Shutdown Scripts
    • Treat init_unreal like __init__
    • Startup Script Management
    • Shutdown Script Management
    • Python Module Example
  • Using Engine-Version Specific Code
  • UE5 Demo Plugin (GitHub)
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On this page
  • importlib.reload
  • Pre-Loaded modules / libraries
  • Python Project Settings
  • init_unreal.py
  • results
  1. Dev Conveniences

Python Command Line

Tips for the Python Command Line in Unreal

Last updated 1 month ago

importlib.reload

When developing Unreal Python tools I regularly using the Python input on the Output Log Window:

We don't always need to relaunch Unreal to try out a few changes to a module's logic, in the Output Log window we can run importlib.reload:

from importlib import reload
from demo import bp_library
    
reload(bp_library)

# Result: Display: Reload/Re-instancing Complete: 1 class changed

This will even reload Blueprint Function libraries, although caution is advised to make sure you're updating the BP Graph / any downstream dependencies for your code development.

Pre-Loaded modules / libraries

If you find yourself constantly using the same modules in the Output Log's Python command line, we can make them available by default in one of two ways.

Python Project Settings

The first method is to add our imports to the Project Setting's Python section, anything in there will be accessible from the Python command line in the Editor:

init_unreal.py

Another method is with an init_unreal.py file, any imports, classes, or functions declared in one of these files will also be added to the main namespaces accessible from the Python command line in the Editor:

results

Both options will load these modules/functions for us, making them accessible right away in the Python command line: