This function removes duplicate values from an array by returning a new one. function removeDuplicatesBy(keyFn, array) { var mySet = new Set(); return array.filter(function(x) { var key = keyFn(x), isNew = !mySet.has(key); if (isNew) mySet.add(key); return isNew; }); } var values = [{color: “red”}, {color: “blue”}, {color: “red”, number: 2}]; var withoutDuplicates = removeDuplicatesBy(x => … Read more
Convert the key from a string to a symbol, and do a lookup in the hash. hash = {:key1 => “value1”, :key2 => “value2”} k = ‘key1′ hash[k.to_sym] # or iow, hash[:key1], which will return “value1” Rails uses this class called HashWithIndifferentAccess that proves to be very useful in such cases. I know that you’ve … Read more
Do it the right way and register default values. NSDictionary *userDefaultsDefaults = @{ @”SomeKey”: @NO, @”AnotherKey”: @”FooBar”, @”NumberKey”: @0, }; [NSUserDefaults.standardUserDefaults registerDefaults:userDefaultsDefaults]; do this before you use anything from NSUserDefaults. The beginning of application:didFinishLaunchingWithOptions: is a safe place. You have to register the defaults each time the app launches. NSUserDefaults only stores values that have … Read more
Use .push: items.push({‘id’:5});
You can use a java Map and map a char to an int. You can then iterate over the characters in the string and check if they have been added to the map, if they have, you can then increment its value. For example: Map<Character, Integer> map = new HashMap<Character, Integer>(); String s = “aasjjikkk”; … Read more
I would suggest to have a look at LMDB (which is the most efficient engine for OpenLDAP, and used in a number of other open-source projects). LMDB is an embedded key/value store, with a Berkeley-DB or LevelDB like API, does not have to store everything in memory, and can support access from multiple processes. There … Read more
In object literal terms, b is a property. Properties are either strings or symbols in JavaScript, although when defining the property name inside an object literal you may omit the string delimiters. for (key in a) { alert(typeof key); //-> “string” }
This happens because KeyValuePair<TKey, TValue> does not define a custom == operator and is not included in the predefined list of value types that can use it. Here is a link to the MSDN documentation for that operator. For predefined value types, the equality operator (==) returns true if the values of its operands are … Read more
One option if the number of keys is small is to use chained gets: value = myDict.get(‘lastName’, myDict.get(‘firstName’, myDict.get(‘userName’))) But if you have keySet defined, this might be clearer: value = None for key in keySet: if key in myDict: value = myDict[key] break The chained gets do not short-circuit, so all keys will be … Read more