In C++ check if std::vector contains a certain value [duplicate]

Answer 1

std::find().

Answer 2

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...";

Answer 3

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>.

Answer 4

1. 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()) { ...
   

2. If your vector is kept sorted, use std::binary_search, it offers logarithmic complexity as well.

3. If all else fails, fall back to std::find, which is a simple linear search.

Answer 5

it's in <algorithm> and called std::find.