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replacefirst helper

Tom Santiago
Updated

Replaces only the first occurrence of a specified substring in a string with another value. Use it when you want to substitute the first match but leave later matches unchanged.

Usage 

{{replacefirst str a b}}

  • str: input string

  • a: substring to replace

  • b: replacement string

Examples

  1. Replace the first occurrence of a character 

    {{replacefirst record.text "a" "z"}}

    Input: 

    { "record": { "text": "a b a b a b" } }

    Output: 

    z b a b a b

  2. Replace only the first word 

    {{replacefirst record.note "Order" "Invoice"}}

    Input: 

    { "record": { "note": "Order Order Order" } }

    Output: 

    Invoice Order Order

Tip

  • Only the first matching substring is replaced; later matches remain unchanged.

  • Matching is case-sensitive—"A" and "a" are treated differently.

  • Use this helper when you need to replace a predictable prefix, tag, or marker without altering the rest of the string.