represent list with no entries

Question

very simple how would you represent a list with no entries

Yacoby · Accepted Answer · 2011-03-15T19:54:57.323

4

An empty list is simply []

For example, defining a variable that holds an empty list can be done by:

emptyList :: [a]
emptyList = []

edited Mar 15 '11 at 19:54

answered Mar 15 '11 at 19:33

Yacoby

@delnan Thanks for pointing that out. I wasn't aware that there was a difference in terminology, however thinking of a function (mathematically) as `emptyList : [a] -> [a]` I suppose it wouldn't make sense to call something with no arguments a function. – Yacoby Mar 15 '11 at 19:58
That's not a variable either. (its value can not be varied) – Rotsor Mar 16 '11 at 01:56
1

@Rotsor immutable variable are still variables ! See http://stackoverflow.com/questions/993124/does-haskell-have-variables – David V. Mar 16 '11 at 07:37

score 1 · Answer 2 · answered Mar 15 '11 at 20:51

1

Also, "" is an empty String, and Strings are just lists of Chars.

answered Mar 15 '11 at 20:51

Dan Burton

2 Answers2