Text Operations

In ComfyUI, text mostly shows up as prompts. Automating a few operations, like replacing part of a string or adding trigger words to a prompt an LLM wrote, makes your workflows more convenient.

What is a string?

In programming, text is called a string to tell it apart from numbers and other data.

  • apple → 5-character string
  • 123 → Looks like a number, but is actually a string treated as text
  • " " (Space) → Invisible, but a 1-character string

Basic Operation Nodes

String Node (Text Input)

The basic node for entering a string. Use the String (Multiline) node to enter text with line breaks.

Concatenate Node (Text Joining)

Combines multiple strings into one. (Example: apple + pen → applepen)

  • delimiter is the separator. You can use anything you like (a comma, a line break, etc.).

Format Text Node

format_text.json

This node lets you create a text template and insert other strings into it.

It can combine text more flexibly than Concatenate.

For example, if you connect apple to a and red to b, then write {a} is {b}. in format, it creates a string like apple is red..

Replace Node (Text Replacement)

Replaces the specified text with other text. (Example: apple pen → orange pen)

Substring Node (Text Extraction)

Extracts the characters in a specified range. (Example: apple → ppl)

  • Cuts out the characters from position start to position end.

Trim Text Node (Remove Spaces)

Removes spaces at the start and end of a string. (Example: apple → apple)

  • Unglamorous but important: it prevents errors from stray spaces in things like user input.

Length Node (Character Count)

Counts the length of the text. (Example: apple → 5)

  • Spaces and line breaks are also counted as 1 character.
  • The output is an int (number).

Advanced Operations (Regular Expressions)

These use a pattern syntax called regular expressions (Regex) for more complex searching and replacing.

Regex Extract Node

Uses a regular expression to extract matching text.

Regex Replace Node

Uses a regular expression to replace matching text.

Power Puter (rgthree)

The Power Puter from rgthree-comfy that came up in Simple Math can take and output strings too, so you can handle text flexibly, including everything covered above.

power_puter_rgthree_replace.json