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Macaulay2 > The Macaulay2 language > operators > #

# -- length, or access to elements

Description

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.

See also

#? -- check for presence of elements

Ways to use `#` :

# BasicList -- length
# HashTable -- length
# Set -- cardinality
# String -- length
BasicList # ZZ -- get element from list
Database # String -- get value from database
HashTable # Thing -- get value from hash table
String # ZZ -- get character from string

For the programmer

The object # is a keyword.