In C++ check if std::vector<string> contains a certain value
You can use std::find
as follows:
if (std::find(v.begin(), v.end(), "abc") != v.end())
{
// Element in vector.
}
To be able to use std::find
: include <algorithm>
.
If your container only contains unique values, consider using
std::set
instead. It allows querying of set membership with logarithmic complexity.std::set<std::string> s; s.insert("abc"); s.insert("xyz"); if (s.find("abc") != s.end()) { ...
If your vector is kept sorted, use
std::binary_search
, it offers logarithmic complexity as well.If all else fails, fall back to
std::find
, which is a simple linear search.
In C++11, you can use std::any_of
instead.
An example to find if there is any zero in the array:
std::array<int,3> foo = {0,1,-1};
if ( std::any_of(foo.begin(), foo.end(), [](int i){return i==0;}) )
std::cout << "zero found...";