Method LRem

structure/list.go:283–326

LRem removes elements from a list associated with a key based on the count and value parameters. The count can have the following values: count > 0: Remove count occurrences of the value from the beginning of the list. count < 0: Remove count occurrences of the value from the end of the list. count

(key string, count int, value interface{})

// count = 0: Remove all occurrences of the value from the list.
// If the key does not exist, an error is returned.
func (l *ListStructure) LRem(key string, count int, value interface{}) error {
	// Get the list
	lst, _, err := l.getListFromDB(key, false)
	if err != nil {
		return err
	}
	var expirationTime time.Duration
	// Process different counts
	if count != 0 {
		prev, curr := lst.Head, lst.Head
		for i := 0; (count > 0 && i < count || count < 0 && lst.Length+i > -count) && curr != nil; {
			if l.valueEqual(curr.Value, value) {
				if curr == lst.Head {
					lst.Head = curr.Next
				} else {
					prev.Next = curr.Next
				}
				i++
				lst.Length--
			} else {
				prev = curr
			}
			curr = curr.Next
		}
	} else {
		prev, curr := lst.Head, lst.Head
		for curr != nil {
			if l.valueEqual(curr.Value, value) {
				if curr == lst.Head {
					lst.Head = curr.Next
				} else {
					prev.Next = curr.Next
				}
				lst.Length--
			} else {
				prev = curr
			}
			curr = curr.Next
		}
	}

	// Store to db
	return l.setListToDB(key, lst, expirationTime)
}

// LSet sets the value of an element in a list associated with a key based on the index.
// If the index is out of range, an error is returned.