This will convert the dict_keys object to a list: list(newdict.keys()) On the other hand, you should ask yourself whether or not it matters. It is Pythonic to assume duck typing — if it looks like a duck and it quacks like a duck, it is a duck. The dict_keys object can be iterated over just … Read more
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The instance initialiser is just syntactic sugar in this case, right? I don’t see why you need an extra anonymous class just to initialize. And it won’t work if the class being created is final. You can create an immutable map using a static initialiser too: public class Test { private static final Map<Integer, String> … Read more
max(stats, key=stats.get)
Python never implicitly copies objects. When you set dict2 = dict1, you are making them refer to the same exact dict object, so when you mutate it, all references to it keep referring to the object in its current state. If you want to copy the dict (which is rare), you have to do so … Read more
Note: for Python 3.7+, see this answer Standard Python dictionaries are unordered (until Python 3.7). Even if you sorted the (key,value) pairs, you wouldn’t be able to store them in a dict in a way that would preserve the ordering. The easiest way is to use OrderedDict, which remembers the order in which the elements … Read more
All Versions In case you happen to need just a single entry: There is Collections.singletonMap(“key”, “value”). For Java Version 9 or higher: Yes, this is possible now. In Java 9 a couple of factory methods have been added that simplify the creation of maps : // this works for up to 10 elements: Map<String, String> … Read more
Use a dict comprehension (Python 2.7 and later): {key: value for (key, value) in iterable} Alternatively for simpler cases or earlier version of Python, use the dict constructor, e.g.: pairs = [(‘a’, 1), (‘b’, 2)] dict(pairs) #=> {‘a’: 1, ‘b’: 2} dict([(k, v+1) for k, v in pairs]) #=> {‘a’: 2, ‘b’: 3} Given separate … Read more
Like this: keys = [‘a’, ‘b’, ‘c’] values = [1, 2, 3] dictionary = dict(zip(keys, values)) print(dictionary) # {‘a’: 1, ‘b’: 2, ‘c’: 3} Voila 🙂 The pairwise dict constructor and zip function are awesomely useful.
Here’s a generic-friendly version: public class MapUtil { public static <K, V extends Comparable<? super V>> Map<K, V> sortByValue(Map<K, V> map) { List<Entry<K, V>> list = new ArrayList<>(map.entrySet()); list.sort(Entry.comparingByValue()); Map<K, V> result = new LinkedHashMap<>(); for (Entry<K, V> entry : list) { result.put(entry.getKey(), entry.getValue()); } return result; } }