std::remove_if - lambda，不从集合中删除任何内容
好吧，我想我在这里犯了一个愚蠢的错误.我有一个 DisplayDevice3d 列表，每个 DisplayDevice3d 都包含一个 DisplayMode3d 列表.我想从 DisplayDevice3d 列表中删除所有没有任何 DisplayMode3d 的项目.我正在尝试使用 Lambda 来做到这一点，即:
Ok, I expect I've made a dumb mistake here. I have a list of DisplayDevice3d and each DisplayDevice3d contains a list of DisplayMode3d. I want to remove all items from the list of DisplayDevice3d that don't have any DisplayMode3d's. I'm trying to use a Lambda to do it, ie.:
// If the device doesn't have any modes, remove it.
std::remove_if(MyDisplayDevices.begin(), MyDisplayDevices.end(),
[](DisplayDevice3d& device)
{
return device.Modes.size() == 0;
}
);
即使在 MyDisplayDevices 中的 6 个 DisplayMode3d 中，只有 1 个在其 Modes 集合中有任何 DisplayMode3d，但没有从列表中删除任何内容.
Even though out of 6 DisplayMode3d's in MyDisplayDevices, only 1 has any DisplayMode3d's in its Modes collection, nothing is being removed from the list.
我在这里犯了什么大错?
What numpty mistake have I made here?
好吧，我的错误是我应该使用 MyDisplayDevices.remove_if 而不是 std::remove_if，但是下面的答案对于使用 std::remove_if :p 是正确的.
Ah ok, my mistake was I should be using MyDisplayDevices.remove_if instead of std::remove_if, however the answers below are correct for use of std::remove_if :p.
MyDisplayDevices.remove_if( [](DisplayDevice3d const & device)
{
return device.Modes.size() == 0;
});
推荐答案
你需要对 remove_if 返回的迭代器调用erase，它应该是这样的:
You need to call erase on the iterator returned from remove_if, It should look something like this:
auto new_end = std::remove_if(MyDisplayDevices.begin(), MyDisplayDevices.end(),
[](const DisplayDevice3d& device)
{ return device.Modes.size() == 0; });
MyDisplayDevices.erase(new_end, MyDisplayDevices.end());
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