Substring

Input

value

Extract substring from value

transformation:

substring

Extract substring from text with start and optional end positions

source:value

parameters

start

Starting character position (0-based)

end

Ending character position (optional, extracts to end if not specified)

Output

value
Hello
Fonta
Subst
Hi
A

* Sample inputs run locally in your browser using the same operation logic as Fontana Flow.
Results are illustrative, not connected to a workflow.

Extract substring from text with start and optional end positions.

Parameters

• start (Start Position, number, required) — Starting character position (0-based). Examples: 0, 5, 10.
• end (End Position, number, optional) — Ending character position (optional, extracts to end if not specified). Examples: 10, 20.

Field selection

• source — Field whose values this operation reads. Omit to apply to all fields on the row.
• target — Optional output field. When omitted, the source field is updated in place.

JSON Configuration

{
  "id": "op-substring",
  "type": "transformation",
  "action": "substring",
  "params": {
    "start": 0,
    "end": 5
  },
  "testInputs": [
    "Hello World",
    "Fontana",
    "Substring Demo",
    "Hi",
    "A",
    ""
  ]
}