To get a shallow copy, just use the constructor of Dictionary<TKey, TValue> as it takes an IEnumerable<KeyValuePair<TKey, TValue>>. It will add this collection into the new instance. Dictionary<int, int> flagsn = new Dictionary<int, int>(flags);
You can actually do this: std::map<std::string, int> mymap = {{“one”, 1}, {“two”, 2}, {“three”, 3}}; What is actually happening here is that std::map stores an std::pair of the key value types, in this case std::pair<const std::string,int>. This is only possible because of c++11’s new uniform initialization syntax which in this case calls a constructor overload … Read more
let maximum = data.reduce(0.0) { max($0, $1.1) } Just a quick way using reduce. or: data.values.max() Output: print(maximum) // 5.828
This is an instance of a fold. You can either write it concisely like this: from functools import reduce import operator def find(element, json): return reduce(operator.getitem, element.split(‘.’), json) Or more Pythonically (because reduce() is frowned upon due to poor readability) like this: def find(element, json): keys = element.split(‘.’) rv = json for key in keys: … Read more
Well the pair can’t exist if the key doesn’t exist… so fetch the value associated with the key, and check whether that’s the value you were looking for. So for example: // Could be generic of course, but let’s keep things simple… public bool ContainsKeyValue(Dictionary<string, int> dictionary, string expectedKey, int expectedValue) { int actualValue; if … Read more
keys, values = zip(*d.items())
Had the same issue and solved this as described below without any additional imports being required and only a few lines of code. Tested with Python 3.6.9. Get position of key ‘Age’ because the new key value pair should get inserted before Get dictionary as list of key value pairs Insert new key value pair … Read more
Your list of tuples adds an extra layer. You have 3 layers of items: The outer list of length 1 million, so 1 million pointers 1 million 2-slot tuples, so 2 million pointers 2 million references to 1 million integer values while your dict only holds: The dict (including 1 million cached hashes) with 2 … Read more
This code: keys = sorted(attributes.keys(), reverse=True) result = [] for key in keys: result.append(attributes[key]) Is basically the use case for which list comprehensions were invented: result = [attributes[key] for key in sorted(attributes.keys(), reverse=True)]
As far as I can tell, the issue isn’t caused by map::emplace, but by pair‘s constructors: #include <map> struct A { A(int) {} A(A&&) = delete; A(A const&) = delete; }; int main() { std::pair<int, A> x(1, 4); // error } This code example doesn’t compile, neither with coliru’s g++4.8.1 nor with clang++3.5, which are … Read more