sorting

问题 I have an Android app that let the user books appointments with date & time pickers, when User books an appointment, it records the appointment date & time on the firebase real-time database as a string like this (29/01/2020 - 10:30), I want to receive all the appointments that is saved on the firebase from another activity but sorted by date (newest at top) For example it should be sorted like this: 3/1/2021 9:00 9/12/2020 10:30 8/11/2020 17:00 8/11/2020 15:30 6/10/2020 10:30 6/10/2020 10:00

问题 I have an Android app that let the user books appointments with date & time pickers, when User books an appointment, it records the appointment date & time on the firebase real-time database as a string like this (29/01/2020 - 10:30), I want to receive all the appointments that is saved on the firebase from another activity but sorted by date (newest at top) For example it should be sorted like this: 3/1/2021 9:00 9/12/2020 10:30 8/11/2020 17:00 8/11/2020 15:30 6/10/2020 10:30 6/10/2020 10:00

问题 I have an Android app that let the user books appointments with date & time pickers, when User books an appointment, it records the appointment date & time on the firebase real-time database as a string like this (29/01/2020 - 10:30), I want to receive all the appointments that is saved on the firebase from another activity but sorted by date (newest at top) For example it should be sorted like this: 3/1/2021 9:00 9/12/2020 10:30 8/11/2020 17:00 8/11/2020 15:30 6/10/2020 10:30 6/10/2020 10:00

问题 Basically, I need to sort a list of Strings based on a very specific criteria, however, it's not so specific that I believe it needs its own comparator. Collections.Sort gets me about 95% the way there as most of its natural sorting, however, for strings like: "-&4" and "%B", it will prioritize "%B" over "-&4". What I'd like is it to be sorted on the first alphanumeric character, so it would be comparing: "4" and "B", putting: "-&4" first then "%B". Doing a replaceall on special characters

问题 Basically, I need to sort a list of Strings based on a very specific criteria, however, it's not so specific that I believe it needs its own comparator. Collections.Sort gets me about 95% the way there as most of its natural sorting, however, for strings like: "-&4" and "%B", it will prioritize "%B" over "-&4". What I'd like is it to be sorted on the first alphanumeric character, so it would be comparing: "4" and "B", putting: "-&4" first then "%B". Doing a replaceall on special characters

问题 I need to sort a text file in ascending order. Each line of the text file starts with an index, as seen below: 2 0 4 0d 07:00:38.0400009155273 3 0 4 0d 07:00:38.0400009155273 1 0 4 0d 07:00:38.0400009155273 The idea result would be as follows: 1 0 4 0d 07:00:38.0400009155273 2 0 4 0d 07:00:38.0400009155273 3 0 4 0d 07:00:38.0400009155273 Please note, this text file has +3 million rows and each element is naturally considered a string. I've been messing around with this for sometime now

问题 I need to sort a text file in ascending order. Each line of the text file starts with an index, as seen below: 2 0 4 0d 07:00:38.0400009155273 3 0 4 0d 07:00:38.0400009155273 1 0 4 0d 07:00:38.0400009155273 The idea result would be as follows: 1 0 4 0d 07:00:38.0400009155273 2 0 4 0d 07:00:38.0400009155273 3 0 4 0d 07:00:38.0400009155273 Please note, this text file has +3 million rows and each element is naturally considered a string. I've been messing around with this for sometime now

问题 class Person { private String name; private String profession; } profession has values: engineer Doctor Teacher student I have list of person and want to sort it on the basis of Profession. engineer comes first then Doctor and then Teacher and then student. Is it possible to sort it with comparable interface. 回答1: You can sort your custom object using Collection.sort method like this, Collections.sort(list, new Comparator(){ public int compare(Object o1, Object o2) { Person p1 = (Person) o1;

问题 Is it possible to sort IQueryable collection by it's sub collections? For example I have a Books collection. I also have an Authors collection which has a column BookId , so the BookId is a foreign key in Authors table. The relation is one-to-many (one book many authors). I need to sort the Books collection by the first author. The book is not required to have an author. Can this be done in Entity Framework and Linq? 回答1: The answer to your concrete question (after clarification that The

问题 I have a large list of items, each item has a weight. I'd like to select N items randomly without replacement, while the items with more weight are more probable to be selected. I'm looking for the most performing idea. Performance is paramount. Any ideas? 回答1: If you want to sample items without replacement, you have lots of options. Use a weighted-choice-with-replacement algorithm to choose random indices. There are many algorithms like this. One of them is WeightedChoice , described later