I can't开发者_开发百科 distinguish these symbols:
=
and =:=
\=
and =\=
[X,Y]
and [X|Y]
What’s the difference ?
For the comparison operators (=
, =:=
, \=
, =\=
):
=
succeeds if the terms unify (basically, if they're bound together)=:=
succeeds if the values of the terms are equal (should be equivalent to=
if you're dealing with numbers, I believe)\=
is the negation of=
=\=
is the negation of=:=
For more info about these operators and more, see this page.
For the list operators, [X|Y]
is a way to refer to a list where X
is the first element and Y
is the list of the remaining elements. [X, Y]
is just another way to refer to this, but it limits Y
to being a single element, instead of possibly a whole list of them. For more info, see this section of the same page.
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