sorting

问题 I am trying to find a nice way to sort a 2d list , first by the 1st value , and then by the 2nd value. I think an example will be the best If I have a list [[1,4], [2,7], [10,1], [1,2], [10,6] [2,1]] I want that is will be sorted like this [[1,2], [1,4], [2,1], [2,7], [10,1], [10,6]] 回答1: l=[[1,4], [2,7], [10,1], [1,2], [10,6], [2,1]] print sorted(l,key=lambda x: (x[0],x[1])) # use lambda to sort by "x[0]"-> first element of the sublists or x[1] -> second element, if its a tie [[1, 2], [1, 4]

问题 I am trying to find a nice way to sort a 2d list , first by the 1st value , and then by the 2nd value. I think an example will be the best If I have a list [[1,4], [2,7], [10,1], [1,2], [10,6] [2,1]] I want that is will be sorted like this [[1,2], [1,4], [2,1], [2,7], [10,1], [10,6]] 回答1: l=[[1,4], [2,7], [10,1], [1,2], [10,6], [2,1]] print sorted(l,key=lambda x: (x[0],x[1])) # use lambda to sort by "x[0]"-> first element of the sublists or x[1] -> second element, if its a tie [[1, 2], [1, 4]

问题 I am trying to find a nice way to sort a 2d list , first by the 1st value , and then by the 2nd value. I think an example will be the best If I have a list [[1,4], [2,7], [10,1], [1,2], [10,6] [2,1]] I want that is will be sorted like this [[1,2], [1,4], [2,1], [2,7], [10,1], [10,6]] 回答1: l=[[1,4], [2,7], [10,1], [1,2], [10,6], [2,1]] print sorted(l,key=lambda x: (x[0],x[1])) # use lambda to sort by "x[0]"-> first element of the sublists or x[1] -> second element, if its a tie [[1, 2], [1, 4]

问题 new Set(['b', 'a', 'c']).sort() throws TypeError: set.sort is not a function . How can I sort a Set to ensure a particular iteration order? 回答1: A set is not an ordered abstract data structure. A Set however always has the same iteration order - element insertion order [1], so when you iterate it (by an iterating method, by calling Symbol.iterator , or by a for.. of loop) you can always expect that. You can always convert the set to an array and sort that. Array.from(new Set(["b","a","c"]))

问题 These are the key/values in JSON [ { "country":"First", "coupon":["1"] }, { "country":"First", "coupon":["10"] }, { "country":"First", "coupon":["12"] }, { "country":"Second", "coupon":"2" }, { "country":"third", "coupon":"3" }, { "country":"fourth", "coupon":"4" }, { "country":"fifth", "coupon":"5" } ] I sorted out the duplicates in JSON and displayed on dropdown var sortedCountries = []; if (sortedCountries.indexOf(value.country) == -1) { $('#sel').append('<option value="' + value.coupon +

问题 I've have a ArrayList of ArrayList what I want to achive is , to sort them in decending order (based on Highest to lowest List size ) to get largest first and onwards. I did same thing in java using Collections.It worked perfectly fine there but now I'm unable to achieve this in Koltin i'm getting ERROR. Consider I've have class Foo() private var allHistoryList: ArrayList<ArrayList<Foo>> = arrayListOf() /** * Sorting array of array list to get Biggest to smallest array List based of size */

问题 I'm using a tool that generates the Postgresql query below: SELECT "id", "score" FROM "players" WHERE "score" > '11266' OR ( "score" = '11266' AND "id" > '4482' ) ORDER BY "score" ASC, "id" ASC LIMIT 3 I need to understand why the OR operator? My players table can have many rows with the same score but not the same id . Is that OR needed when multiple rows has the same score value? 回答1: The purpose of the OR -- as you suspect -- is to handle the case where there are ties in the scores. The

问题 I'm using a tool that generates the Postgresql query below: SELECT "id", "score" FROM "players" WHERE "score" > '11266' OR ( "score" = '11266' AND "id" > '4482' ) ORDER BY "score" ASC, "id" ASC LIMIT 3 I need to understand why the OR operator? My players table can have many rows with the same score but not the same id . Is that OR needed when multiple rows has the same score value? 回答1: The purpose of the OR -- as you suspect -- is to handle the case where there are ties in the scores. The

问题 I am building a sorting visualization. I started with a simple bubble sort. When I sort a small array everything is fine and the visualization looks good no matter the speed, but when I visualize a large array there is a delay and the visualization seems to start a few steps ahead and not showing some of the first steps. Why is it happening? This is my Code: import React, { useContext, useState, useEffect } from 'react'; const NUMBER_OF_ELEMENTS = 10; const DEFAULT_COLOR = 'black'; const

问题 In my web app XY I'm showing a classic list/table of data (documents) to the user. While all the sort functions provided by MongoDB ( and Mongoose, i'm using Mongoose) are pretty clear to me, I'm not interested in sorting by date or alphabetical order. In my case it would be important to let the user maintain a custom sort as in manually drag/drop items around to set a specific order of the documents (e.g. putting favourites in top of the list ). The UI to do this is a no-brainer but how to