stl remove_if与类成员函数结果 [英] stl remove_if with class member function result
问题描述
我有一个对象容器,列表;和Foo类具有成员函数id()返回整数标识符。
现在,我想使用stl算法remove_if删除一些ID小于值的对象。
我不想提供一个用于进行ID比较的功能,如果我可以用STL编写一行代码,但可以提高实现的可能性。
I have a object container, list; and class Foo have a member function id() return an integer identifier. Now I want to use stl algorithm remove_if to remove some objects whose id is less than a value. I don't want to provide a function for id compare, If it is possible for me to write one line code with STL but boost to implement it.
class Foo{
public:
unsigned id() const {return id_;}
...
private:
unsigned id_
...
};
list<Foo> foo_list;
std::remove_if(foo_list.begin(), foo_list.end(), ???);
如果STL仅使用std :: bind2nd,stl :: less(),std: :mem_fun_ref()或其他stl函数。
If STL can do this with only std::bind2nd, stl::less(), std::mem_fun_ref() or other stl functions.
推荐答案
是的,如果您同意更改 Foo
的界面。
Yes, that is possible to achieve without lambdas, if you agree to change the interface of Foo
a little bit.
class Foo
{
public:
Foo(unsigned id)
: id_(id) {}
bool is_equal(unsigned id) const
{ return id_ == id; }
private:
unsigned id_;
};
typedef list<Foo> FooList;
FooList foo_list;
foo_list.push_back(Foo(1));
foo_list.push_back(Foo(2));
unsigned to_remove = 1;
foo_list.remove_if(std::bind2nd(std::mem_fun_ref(&Foo::is_equal), to_remove));
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