Accessing 'key' and 'value' in std algorithms

[MartinFlores751]

Is there any way to do something like the following:

const auto comparison_func{[&other_json](const auto _iter) {
    if (other_json.contains(_iter.key()) && other_json[_iter.key()] == _iter.value()) {
        return true; 
    } 
    return false; 
}};

// Ensure 'other_json' has all elements in 'must_match'
if (std::all_of(std::cbegin(must_match), std::cend(must_match), comparison_func)) { 
    // Do something if there's a match
} 

I understand that you can access the key and value using range-based for loops, but was curious about this method.

In my testing it doesn't work, but it could just be me mishandling or misunderstanding something, so I thought it would be good to ask.

[nlohmann]

You may want to check https://json.nlohmann.me/api/basic_json/items/

[MartinFlores751]

Thank you for pointing that out.

I got this to work by changing the following:

  const auto comparison_func{[&other_json](const auto _iter) {
      if (other_json.contains(_iter.key()) && other_json[_iter.key()] == _iter.value()) {
          return true; 
      } 
      return false; 
  }};

  // Ensure 'other_json' has all elements in 'must_match'
+ auto match_items{must_match.items()};
- if (std::all_of(std::cbegin(must_match), std::cend(must_match), comparison_func)) {
+ if (std::all_of(std::begin(match_items), std::end(match_items), comparison_func)) { 
    // Do something if there's a match
  }