在 std: : multiset 中，如果找到一个元素，就有一个函数或算法来擦除一个样本(单一或重复)

也许这是一个副本，但我没有找到任何搜索: 在 std::multiset上调用 erase(value)时，删除所有找到值的元素。我能想到的唯一解决办法就是:

std::multiset<int>::iterator hit(mySet.find(5));
if (hit!= mySet.end()) mySet.erase(hit);

这个不错，但我觉得还有更好的办法，有什么主意吗？

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小开

I would try the following.

First call equal_range() to find the range of elements that equal to the key.

If the returned range is non-empty, then erase() a range of elements (i.e. the erase() which takes two iterators) where:

  • the first argument is the iterator to the 2nd element in the returned range (i.e. one past .first returned) and

  • the second argument as the returned range pair iterator's .second one.

Edit after reading templatetypedef's (Thanks!) comment:

If one (as opposed to all) duplicate is supposed to be removed: If the pair returned by equal_range() has at least two elements, then erase() the first element by passing the the .first of the returned pair to single iterator version of the erase():

Pseudo-code:

pair<iterator, iterator> pit = mymultiset.equal_range( key );


if( distance( pit.first, pit.second ) >= 2 ) {
mymultiset.erase( pit.first );
}
小开

In fact, the correct answer is:

my_multiset.erase(my_multiset.find(value));
小开

We can do something like this:

multiset<int>::iterator it, it1;
it = myset.find(value);
it1 = it;
it1++;
myset.erase (it, it1);
小开 
auto itr = my_multiset.find(value);
if(itr!=my_multiset.end()){
my_multiset.erase(itr);
}

I would imagine there is a cleaner way of accomplishing the same. But this gets the job done.

小开 
 if(my_multiset.find(key)!=my_multiset.end())
my_multiset.erase(my_multiset.equal_range(key).first);

This is the best way i can think of to remove a single instance in a multiset in c++

小开

Try this one:

multiset<int> s;
s.erase(s.lower_bound(value));

As long as you can ensure that the value exists in the set. That works.

小开

This worked for me:

multi_set.erase(multi_set.find(val));

if val exists in the multi-set.

小开 
 auto itr=ms.find(value);
while(*itr==value){
ms.erase(value);
itr=ms.find(value);
}

Try this one It will remove all the duplicates available in the multiset.

小开

Here is a more elegant solution using "if statement with initializer" introduced in C++17:

if(auto it = mySet.find(value); it != mySet.end())
mySet.erase(value);

The advantage of this syntax is that the scope of the iterator it is reduced to this if statement.


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