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std::list<T,Allocator>::splice

void splice( const_iterator pos, list& other );	(1)
void splice( const_iterator pos, list&& other );	(2)	(since C++11)
void splice( const_iterator pos, list& other, const_iterator it );	(3)
void splice( const_iterator pos, list&& other, const_iterator it );	(4)	(since C++11)
void splice( const_iterator pos, list& other, const_iterator first, const_iterator last);	(5)
void splice( const_iterator pos, list&& other, const_iterator first, const_iterator last );	(6)	(since C++11)

Transfers elements from one list to another.

No elements are copied or moved, only the internal pointers of the list nodes are re-pointed. The behavior is undefined if get_allocator() != other.get_allocator(). No iterators or references become invalidated, the iterators to moved elements remain valid, but now refer into *this, not into other.

1,2) Transfers all elements from other into *this. The elements are inserted before the element pointed to by pos. The container other becomes empty after the operation. The behavior is undefined if other refers to the same object as *this.

3,4) Transfers the element pointed to by it from other into *this. The element is inserted before the element pointed to by pos.

5,6) Transfers the elements in the range [first, last) from other into *this. The elements are inserted before the element pointed to by pos. The behavior is undefined if pos is an iterator in the range [first, last).

Parameters

pos	-	element before which the content will be inserted
other	-	another container to transfer the content from
it	-	the element to transfer from `other` to `*this`
first, last	-	the range of elements to transfer from `other` to `*this`

Return value

(none).

Exceptions

Throws nothing.

Complexity

1-4) Constant.

5,6) Constant if other refers to the same object as *this, otherwise linear in std::distance(first, last).

Example

#include <iostream>
#include <list>
 
std::ostream& operator<<(std::ostream& ostr, const std::list<int>& list)
{
    for (auto& i : list)
        ostr << ' ' << i;
 
    return ostr;
}
 
int main ()
{
    std::list<int> list1{1, 2, 3, 4, 5};
    std::list<int> list2{10, 20, 30, 40, 50};
 
    auto it = list1.begin();
    std::advance(it, 2);
 
    list1.splice(it, list2);
 
    std::cout << "list1:" << list1 << '\n';
    std::cout << "list2:" << list2 << '\n';
 
    list2.splice(list2.begin(), list1, it, list1.end());
 
    std::cout << "list1:" << list1 << '\n';
    std::cout << "list2:" << list2 << '\n';
}

Output:

list1: 1 2 10 20 30 40 50 3 4 5
list2:
list1: 1 2 10 20 30 40 50
list2: 3 4 5

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 250	C++98	references and iterators to the moved element(s) were all invalidated	they refer or point to the same element(s) in `*this`

merge	merges two sorted lists (public member function)
removeremove_if	removes elements satisfying specific criteria (public member function)