Python f-strings

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Python f-strings are a powerful new way to format strings in Python. In general, they look like this:

f'This string includes {expression}'

Anything inside the curly-braces is evaluated as a Python expression. You can find full details by searching "Python f-strings" online. This is a good place to start.

f-strings in TouchDesigner

Some TouchDesigner operators allow you to use f-string formatting in various ways. Examples include textCOMP in the parameters and lister in the colDefine table. Different variables will be provided to the f-string for use in expressions. These will be documented in the individual operator pages.


  • {text}! - yields the string held in text followed by an exclamation point
  • {val + 1} - yields val + 1 (works when val is a numeric type only)
  • ${val:.2f} - yields val as a float with two decimal places and a dollar sign before it (works when val is a float only)
  • {me.path}: {text} - yields the operator path where this is being evaluated, followed by a colon, followed by the string held in text

Using f-string Formatting in Your Scripts

To use f-string formatting in your custom scripts, parameters, and components, use the utility function formatString in TDFunctions.