Substring
Description
Pure function returning the substring of text starting at the given index for the given length. Out-of-range indices are clamped to the bounds of the string.
When to use
Use Substring to extract a fixed portion of a string — for example, to read a date prefix from an ISO timestamp or to truncate a long display value. Out-of-range indices are clamped rather than causing an error, so the node is safe to use even when the input length is variable. Combine with String length when you need a dynamic start or length value.
Pins
Input pins
| Pin | Type | Default | Notes |
|---|---|---|---|
| Text | string | — | The source string. Indices are zero-based. |
| Start | integer | 0 | Zero-based index of the first character to include. Clamped to [0, text length] if out of range. |
| Length | integer | 10 | Maximum number of characters to extract. Clamped so the result never exceeds the end of the string. |
Output pins
| Pin | Type | Notes |
|---|---|---|
| Result | string | The extracted substring. May be shorter than length if the string ends first. |
Example
Extract the date portion from an ISO-8601 timestamp. Wire the Result output of Format
date/time into the Text input of Substring with Start set to 0 and Length set to
10. Given a timestamp like "2026-05-15T09:30:00Z", the Result output is
"2026-05-15", which can be wired directly into Log message.