Maps

Maps are a way of storing data with a key-value pair.

C++: Use the map.at() function so that you don't accidentally create new key-value pairs in the map. The preferred way to populate a map with a key-value pair is to use the built-in std::pair class:

std::map<std::string, int> frequency;
frequency.insert(std::pair<std::string, int>("Howdy",1));
// OR
frequency.insert({"Howdy", 1});

This is how you iterate through a map:

for (auto const& [key, value] : your_map) {
  std::cout << key    << ':'    << value    << std::endl;
}

Use std::map.contains(key); to see if a map contains a given key

See Also

1. [[computer-science]]
2. [[Compound Data]]