[input[i:i+n] for i in range(0, len(input), n)] # Use xrange in py2k where n is the length of a chunk. Since you don’t define what might happen to the final element of the new list when the number of elements in input is not divisible by n, I assumed that it’s of no importance: with … Read more
Sure, you can use slice indexing: a_list[1:1] = b_list Just to demonstrate the general algorithm, if you were to implement the my_extend function in a hypothetical custom list class, it would look like this: def my_extend(self, other_list, index): self[index:index] = other_list But don’t actually make that a function, just use the slice notation when you … Read more
This code Future<List<String>> readHeaderData() async { List<String> l = new List(); List<String> files = await readHeaders(); // Gets filenames files.forEach((filename) async { final file = await File(filename); String contents = await file.readAsString(); User user = User.fromJson(json.decode(contents)); String name = user.NameLast + “, ” + user.NameFirst; print(name); l.add(name); } return l; } returns the list l … Read more
Assuming that the dicts line up like in your example input, you can use the zip() function to get a list of associated pairs of dicts, then you can use any() to check if there is a difference: >>> list_1 = [{‘unique_id’:’001′, ‘key1′:’AAA’, ‘key2′:’BBB’, ‘key3′:’EEE’}, {‘unique_id’:’002′, ‘key1′:’AAA’, ‘key2′:’CCC’, ‘key3′:’FFF’}] >>> list_2 = [{‘unique_id’:’001′, ‘key1′:’AAA’, ‘key2′:’DDD’, … Read more
A simple and very readable solution: List<string> results = new List<string>(); foreach (var element in array) { if(results.Count == 0 || results.Last() != element) results.Add(element); }
You can just do (a,). No need to use a function. (Note that the comma is necessary.) Essentially, tuple(a) means to make a tuple of the contents of a, not a tuple consisting of just a itself. The “contents” of a string (what you get when you iterate over it) are its characters, which is … Read more
deque.popleft() is faster than list.pop(0), because the deque has been optimized to do popleft() approximately in O(1), while list.pop(0) takes O(n) (see deque objects). Comments and code in _collectionsmodule.c for deque and listobject.c for list provide implementation insights to explain the performance differences. Namely that a deque object “is composed of a doubly-linked list”, which … Read more
You could use random.sample to generate the list with one call: import random my_randoms = random.sample(range(100), 10) That generates numbers in the (inclusive) range from 0 to 99. If you want 1 to 100, you could use this (thanks to @martineau for pointing out my convoluted solution): my_randoms = random.sample(range(1, 101), 10)
HashSet consumes about 5.5 times more memory than ArrayList for the same number of elements (although they’re both still linear), and has significantly slower iteration (albeit with the same asymptotics); a quick Google search suggests a 2-3x slowdown for HashSet iteration versus ArrayList. If you don’t care about uniqueness or the performance of contains, then … Read more
Classic Example: You want to store point value as tuple of (x, y)