#

#x -- provides the length of a list, sequence, array or string, or the number of elements in a hash table or set.
x#i -- provides the value associated to the key i in the hash table x; or else the i-th element of x if x is a list, array, or sequence; or the i-th character of x if x is a string; or the value stored in the database x under the key i, which must be a string.

If x is a string, then i must be an integer, and x#i is the i-th character in the string, presented as a string of length one, or if i is out of range, a string of length zero is returned. If i is negative, then the i-th character from the end is provided.

Assignment to x#i can change the value if x is mutable.

The precedence of # when used as a binary operator is high, as high as ., but the precedence when used as a unary operator lower, as low as adjacency or function application.

i1 : x = new MutableHashTable



o1 = MutableHashTable{...}



o1 : MutableHashTable

i2 : x#i = p



o2 = p



o2 : Symbol

i3 : x#i



o3 = p



o3 : Symbol