QGIS/resources/function_help/json/if

{
  "name": "if",
  "type": "function",
  "description": "Tests a condition and returns a different result depending on the conditional check.",
  "arguments": [
    {"arg":"condition","description":"the condition which should be checked"},
    {"arg":"result_when_true","description":"the result which will be returned when the condition is true or another value that does not convert to false."},
    {"arg":"result_when_false","description":"the result which will be returned when the condition is false or another value that converts to false like 0 or ''. NULL will also be converted to false."}
  ],
  "examples": [
    { "expression":"if( 1+1=2, 'Yes', 'No' )", "returns":"'Yes'"},
    { "expression":"if( 1+1=3, 'Yes', 'No' )", "returns":"'No'"},
    { "expression":"if( 5 > 3, 1, 0)", "returns":"1"},
    { "expression":"if( '', 'It is true (not empty)', 'It is false (empty)' )", "returns":"'It is false (empty)'"},
    { "expression":"if( ' ', 'It is true (not empty)', 'It is false (empty)' )", "returns":"'It is true (not empty)'"},
    { "expression":"if( 0, 'One', 'Zero' )", "returns":"'Zero'"},
    { "expression":"if( 10, 'One', 'Zero' )", "returns":"'One'"}
  ]
}