Find {expr} in {object} and return its index. See |indexof()| for using a lambda to select the item. If {object} is a |List| return the lowest index where the item has a value equal to {expr}. There is no automatic conversion, so the String "4" is different from the Number 4. And the number 4 is different from the Float 4.0. The value of 'ignorecase' is not used here, case matters as indicated by the {ic} argument. If {object} is |Blob| return the lowest index where the byte value is equal to {expr}. If {start} is given then start looking at the item with index {start} (may be negative for an item relative to the end). When {ic} is given and it is |TRUE|, ignore case. Otherwise case must match. -1 is returned when {expr} is not found in {object}. Example: :let idx = index(words, "the") :if index(numbers, 123) >= 0 Can also be used as a |method|: GetObject()->index(what)