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index(): read a field out of a record

Easy

Return the ri!field value from the record. When the record has no such field, return "unknown".

The second argument is the field name as text.

Inputs

  • ri!person — Map
  • ri!field — Text

ri! Rule Inputs

ri!personMap
a!map(name: "Ann", city: "Pune")
ri!fieldText
"name"

Example 1 — A field that is there

Input: ri!person
a!map(name: "Ann", city: "Pune")
Input: ri!field
"name"
Output:
"Ann"

Example 2 — A different field

Input: ri!person
a!map(name: "Ann", city: "Pune")
Input: ri!field
"city"
Output:
"Pune"

Example 3 — A field the record does not have

Input: ri!person
a!map(name: "Ann")
Input: ri!field
"city"
Output:
"unknown"

Example 4 — A record with nothing in it

Input: ri!person
a!map()
Input: ri!field
"name"
Output:
"unknown"

Appian Expression Tips

  • • Use ri!variableName for rule inputs
  • • Use a!localVariables(local!x: …, body) for locals
  • • Use a!forEach(items: …, expression: fv!item) to iterate
  • • Use where() / reject(fn!isnull, list) to filter