QGIS/resources/function_help/json/try

{
  "name": "try",
  "type": "function",
  "groups": ["Conditionals"],
  "description": "Tries an expression and returns its value if error-free. If the expression returns an error, an alternative value will be returned when provided otherwise the function will return null.",
  "arguments": [
    {"arg":"expression","description":"the expression which should be run"},
    {"arg":"alternative","optional":true,"description":"the result which will be returned if the expression returns an error."}
  ],
  "examples": [
    { "expression":"try( to_int( '1' ), 0 )", "returns":"1"},
    { "expression":"try( to_int( 'a' ), 0 )", "returns":"0"},
    { "expression":"try( to_date( 'invalid_date' ) )", "returns":"NULL"}
  ]
}