sorting

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

问题 I have a file with columns shown below: chr1 91.4062 chr10 97.9150 chr11 116.7630 chr12 106.7870 chr13 116.1050 chr14 126.2180 chr15 110.2320 chr16 96.8076 chr17 113.5970 chr18 86.1011 chr19 130.6770 chr2 111.4620 chr20 68.4864 chr21 107.0810 chr22 140.7750 chr23 110.9590 chr24 68.4785 chr25 102.2080 chr26 72.2762 chr27 96.2213 chr28 85.5570 chr29 126.3800 chr3 116.1830 chr30 89.5663 chr31 89.1227 chr32 128.6190 chr4 117.3620 chr5 78.1921 chr6 85.4915 chr7 107.2620 chr8 112.9560 chr9 69.0250

问题 I have a file with columns shown below: chr1 91.4062 chr10 97.9150 chr11 116.7630 chr12 106.7870 chr13 116.1050 chr14 126.2180 chr15 110.2320 chr16 96.8076 chr17 113.5970 chr18 86.1011 chr19 130.6770 chr2 111.4620 chr20 68.4864 chr21 107.0810 chr22 140.7750 chr23 110.9590 chr24 68.4785 chr25 102.2080 chr26 72.2762 chr27 96.2213 chr28 85.5570 chr29 126.3800 chr3 116.1830 chr30 89.5663 chr31 89.1227 chr32 128.6190 chr4 117.3620 chr5 78.1921 chr6 85.4915 chr7 107.2620 chr8 112.9560 chr9 69.0250

问题 I'm new to pandas and working with tabular data in a programming environment. I have sorted a dataframe by a specific column but the answer that panda spits out is not exactly correct. Here is the code I have used: league_dataframe.sort_values('overall_league_position') The result that the sort method yields values in column 'overall league position' are not sorted in ascending or order which is the default for the method. What am I doing wrong? Thanks for your patience! 回答1: For whatever

问题 I have structure like this: [ {id: 1, afterId: -1}, {id: 5, afterId: 2}, {id: 2, afterId: 4}, {id: 4, afterId: 1}, {id: 3, afterId: 5} ] Edited Requirements : Each object's afterId must be equal to previous object id key; Object with afterId = -1 must be first; Should work even if there is duplicated or missing afterId's; Expected result : [ {id: 1, afterId: -1}, {id: 4, afterId: 1}, {id: 2, afterId: 4}, {id: 5, afterId: 2}, {id: 3, afterId: 5} ] Example: http://jsfiddle.net/z3sfdo1z/ 回答1:

问题 So I have a function that provides the following tuple. keywords: [('notre dame coach brian kelly', 21.0), ('put student-athlete health', 14.5), ('fourth acc game impacted', 12.5), ('student-athlete health', 10.5), ('football-related activities', 9.0), ('resuming team activities', 9.0), ('ongoing testing procedures', 8.0), ('october 3rd weekend', 8.0), ('players tested positive', 7.75), ('irish announced 13 players', 7.25), ('notre dame', 6.0), ('positive results', 4.5), ('players handled', 4

问题 I don't know why I got stuck on a problem that the chatList is not sorting by the last message time or by the most recent message. I have tried by storing timestamp in the database and orderChildBy timestamp but it still not working. This is the way how I created chatList in the firebaseDatabase val timeAgo = Date().time val myTimeMap = HashMap<String, Any?>() myTimeMap["timestamp"] = timeAgo.toString() myTimeMap["id"] = friendId val friendTimeMap = HashMap<String, Any?>() friendTimeMap[

问题 I am trying to sort a list of User Objects by the order in which User IDs appear in the MessageList Array. The MessageList consists of ID's of people a user is chatting with (ordered by time - using sortwith), which is then to be sent to a User Adapter as a list of Users in the same order as the message list. This is so that username, profile image and other details can be displayed... I have learnt a datasnapshot of the Users from firebase provides as is order and hence needs to be ordered

问题 I am trying to sort a list of User Objects by the order in which User IDs appear in the MessageList Array. The MessageList consists of ID's of people a user is chatting with (ordered by time - using sortwith), which is then to be sent to a User Adapter as a list of Users in the same order as the message list. This is so that username, profile image and other details can be displayed... I have learnt a datasnapshot of the Users from firebase provides as is order and hence needs to be ordered

问题 I am trying to sort a list of User Objects by the order in which User IDs appear in the MessageList Array. The MessageList consists of ID's of people a user is chatting with (ordered by time - using sortwith), which is then to be sent to a User Adapter as a list of Users in the same order as the message list. This is so that username, profile image and other details can be displayed... I have learnt a datasnapshot of the Users from firebase provides as is order and hence needs to be ordered