Well, something will have to loop… but in LINQ you could easily use the Concat and ToList extension methods: var bigList = list1.Concat(list2).Concat(list3).ToList(); Note that this will create a new list rather than appending items to an existing list. If you want to add them to an existing list, List<T>.AddRange is probably what you’re after: … Read more
The naive way, sorting the list of (key, value) tuples, using the sorted() function and a custom sort key (called for each (key, value) pair produced by dict.items())): sorted(a.items(), key=lambda pair: a_list.index(pair[0])) The faster way, creating an index map first: index_map = {v: i for i, v in enumerate(a_list)} sorted(a.items(), key=lambda pair: index_map[pair[0]]) This is … Read more
You can do the following, using itertools.chain: >>> from itertools import chain # timeit: ~3.40 >>> [dict(chain(*map(dict.items, d.values()))) for d in data] [{‘l’: ‘Apple’, ‘b’: ‘Milk’, ‘d’: ‘Meatball’, ‘favourite’: ‘coke’, ‘dislike’: ‘juice’}, {‘l’: ‘Apple1’, ‘b’: ‘Milk1’, ‘dislike’: ‘juice3’, ‘favourite’: ‘coke2’, ‘d’: ‘Meatball2’}] The usage of chain, map, * make this expression a shorthand for the … Read more
The primary difference is that quote prevents evaluation of the elements, whereas list does not: user=> ‘(1 2 (+ 1 2)) (1 2 (+ 1 2)) user=> (list 1 2 (+ 1 2)) (1 2 3) For this reason (among others), it is idiomatic clojure to use a vector when describing a literal collection: user=> … Read more
If your code is simply iterating over the sequence inside the method (not adding, removing, or accessing by index), change your method to one of the following DoSomething(IEnumerable<IMyInterface> sequence) DoSomething<T>(IEnumerable<T> sequence) where T : IMyInterface The IEnumerable<> interface is covariant (as of .NET 4) (first option). Or you could use the latter signature if using … Read more
You want to use the Select method, not Where here: _contactList.Select(C => C.FirstName).ToList(); Further, the need for the ToList() only exists because the property demands it. You could return an IEnumerable<string> instead if you wanted to get rid of that.
You need to declare some_method to be generic, as well. void SomeMethod<T>(List<T> someList) { if (typeof(T) == typeof(c1)) { // etc } }
Disclaimer: I don’t use Python, so some things I say may be wrong. Python experts, feel free to correct me. Great question. I think the central misconception (if I can’t even call it that; it’s perfectly reasonable how you arrived at the thought process you used) you’re having that prompts you to ask the question … Read more
The modifier readonly means that the value cannot be assigned except in the declaration or constructor. It does not mean that the assigned object becomes immutable. If you want your object to be immutable, you must use a type that is immutable. The type ReadOnlyCollection<T> that you mentioned is an example of a immutable collection. … Read more
You can do this: s = dict([ (k,r) for k,r in mydict.iteritems() if r[‘x’] > 92 and r[‘x’] < 95 and r[‘y’] > 70 and r[‘y’] < 75 ]) This takes a dict as you specified and returns a ‘filtered’ dict.