Method `-()
- Method `-
mixed `-(mixed arg1)
mixed `-(mixed arg1, mixed arg2, mixed ... extras)
mixed `-(object arg1, mixed arg2)
mixed `-(mixed arg1, object arg2)
int `-(int arg1, int arg2)
float `-(float arg1, int|float arg2)
float `-(int|float arg1, float arg2)
string `-(string arg1, string arg2)
array `-(array arg1, array arg2)
mapping `-(mapping arg1, array arg2)
mapping `-(mapping arg1, mapping arg2)
mapping `-(mapping arg1, multiset arg2)
multiset `-(multiset arg1, multiset arg2)- Description
Negation/subtraction/set difference.
Every expression with the
-
operator becomes a call to this function, i.e.-a
is the same aspredef::`-(a)
anda-b
is the same aspredef::`-(a,b)
. Longer-
expressions are normally optimized to one call, so e.g.a-b-c
becomespredef::`-(a,b,c)
.- Returns
If there's a single argument, that argument is returned negated. If arg1 is an object with an lfun::`-(), that function is called without arguments, and its result is returned.
If there are more than two arguments the result is:
`-(`-(arg1, arg2), @extras)
.Otherwise, if arg1 is an object with an lfun::`-(), that function is called with arg2 as argument, and its result is returned.
Otherwise, if arg2 is an object with an lfun::``-(), that function is called with arg1 as argument, and its result is returned.
Otherwise the result depends on the argument types:
arg1 can have any of the following types:int|float The result is
arg1 - arg2
, and is a float if either arg1 or arg2 is a float.string The result is arg1 with all nonoverlapping occurrences of the substring arg2 removed. In cases with two overlapping occurrences, the leftmost is removed.
array|mapping|multiset The result is like arg1 but without the elements/indices that match any in arg2 (according to `== and, in the case of mappings, hash_value).
The function is not destructive on the arguments - the result is always a new instance.
- Note
In Pike 7.0 and earlier the subtraction order was unspecified.
- See also