core :: Collection :: has_exactly

`other`

?The same elements must be present in both `self`

and `other`

,
but the order of the elements in the collections are not considered.

```
assert [1..3].has_exactly([3,1,2]) == true # the same elements
assert [1..3].has_exactly([3,1]) == false # 2 is not in the array
assert [1..2].has_exactly([3,1,2]) == false
```

Repeated elements must be present in both collections in the same amount. So basically it is a multi-set comparison.

```
assert [1,2,3,2].has_exactly([1,2,2,3]) == true # the same elements
assert [1,2,3,2].has_exactly([1,2,3]) == false # more 2 in the first array
assert [1,2,3].has_exactly([1,2,2,3]) == false
```

Note that the default implementation is general and correct for any lawful Collections.
It is memory-efficient but relies on `count`

so may be CPU-inefficient for some kind of collections.

```
# Does the collection contain exactly all the elements of `other`?
#
# The same elements must be present in both `self` and `other`,
# but the order of the elements in the collections are not considered.
#
# assert [1..3].has_exactly([3,1,2]) == true # the same elements
# assert [1..3].has_exactly([3,1]) == false # 2 is not in the array
# assert [1..2].has_exactly([3,1,2]) == false # 3 is not in the range
#
# Repeated elements must be present in both collections in the same amount.
# So basically it is a multi-set comparison.
#
# assert [1,2,3,2].has_exactly([1,2,2,3]) == true # the same elements
# assert [1,2,3,2].has_exactly([1,2,3]) == false # more 2 in the first array
# assert [1,2,3].has_exactly([1,2,2,3]) == false # more 2 in the second array
#
# Note that the default implementation is general and correct for any lawful Collections.
# It is memory-efficient but relies on `count` so may be CPU-inefficient for some kind of collections.
fun has_exactly(other: Collection[nullable Object]): Bool
do
if length != other.length then return false
for e in self do if self.count(e) != other.count(e) then return false
return true
end
```

lib/core/collection/abstract_collection.nit:162,2--185,4