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"
  }],
  "tags": ["return", "tries", "error", "alternative", "provided", "exception"]
}