std::list::splice

From cppreference.com
< cpp‎ | container‎ | list

void splice( const_iterator pos, list& other );
(1)
void splice( const_iterator pos, list&& other );
(1) (since C++11)
void splice( const_iterator pos, list& other, const_iterator it );
(2)
void splice( const_iterator pos, list&& other, const_iterator it );
(2) (since C++11)
void splice( const_iterator pos, list& other,
             const_iterator first, const_iterator last);
(3)
void splice( const_iterator pos, list&& other,
             const_iterator first, const_iterator last );
(3) (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) 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 this == &other.
2) Transfers the element pointed to by it from other into *this. The element is inserted before the element pointed to by pos.
3) 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)

Complexity

1-2) Constant.

3) Constant if this == &other, 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

See also

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