从包含映射的双端队列中删除元素
delete elements from deque containing maps
我有一个包含映射的双端队列,我正在尝试通过映射键删除一个元素。
那是我的尝试,但没有用:
typedef map<string,string> mmap;
deque<mmap> q_map;
int main()
{
mmap m;
m.insert(std::make_pair("S180","11111111111"));
q_map.push_back(m);
std::cout << q_map.front().find("S180")->first << " " << q_map.front().find("S180")->second << std::endl;
q_map.erase(std::remove(q_map.begin(), q_map.end(), q_map.front().find("S180")->first), q_map.end());
std::cout << "=================================" << std::endl;
}
我总是收到这个错误:
error: cannot convert ‘std::_Deque_iterator<std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >&, std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >*>’ to ‘const char*’ for argument ‘1’ to ‘int remove(const char*)’
你有两个问题。
首先,给您的错误消息是您可能忘记了 #include <algorithm>
声明 std::remove
的地方。因此,您不小心尝试在 <cstdio>
.
中调用具有相同名称但参数不同的函数
第二个问题是您对 std::remove
的调用与 <algorithm>
中的调用也不匹配。声明如下:
template< class ForwardIt, class T >
ForwardIt remove( ForwardIt first, ForwardIt last, const T& value );
并且因为双端队列迭代器的 T
是 mmap
,您必须传递对 mmap
的引用以删除所有具有相等值的 mmap。相反,您传递的是 q_map.front().find("S180")->first
,它是 std::string
.
我有一个包含映射的双端队列,我正在尝试通过映射键删除一个元素。
那是我的尝试,但没有用:
typedef map<string,string> mmap;
deque<mmap> q_map;
int main()
{
mmap m;
m.insert(std::make_pair("S180","11111111111"));
q_map.push_back(m);
std::cout << q_map.front().find("S180")->first << " " << q_map.front().find("S180")->second << std::endl;
q_map.erase(std::remove(q_map.begin(), q_map.end(), q_map.front().find("S180")->first), q_map.end());
std::cout << "=================================" << std::endl;
}
我总是收到这个错误:
error: cannot convert ‘std::_Deque_iterator<std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >&, std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<const std::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >*>’ to ‘const char*’ for argument ‘1’ to ‘int remove(const char*)’
你有两个问题。
首先,给您的错误消息是您可能忘记了 #include <algorithm>
声明 std::remove
的地方。因此,您不小心尝试在 <cstdio>
.
第二个问题是您对 std::remove
的调用与 <algorithm>
中的调用也不匹配。声明如下:
template< class ForwardIt, class T >
ForwardIt remove( ForwardIt first, ForwardIt last, const T& value );
并且因为双端队列迭代器的 T
是 mmap
,您必须传递对 mmap
的引用以删除所有具有相等值的 mmap。相反,您传递的是 q_map.front().find("S180")->first
,它是 std::string
.