tuples

问题 My SCHEMA is the following and I have ~ 4m existing posts in the DB that I need to update. I am adding an integer which points to a text location. CREATE TABLE app_post ( id integer NOT NULL, text_location integer, title character varying(140) ); I want to update existing records with a long (1000-5000) list of tuples that represent (id, text_location): [(1, 123), (2,3), (9, 10)....] What is the most efficient way to do this? 回答1: If you are generating the values on the fly using phyton, you

问题 I have string of tuples LL = [ ("text1",2,3,N/A), ("text2",N/A,5,6),("text3",N/A,5,N/A) ] I need LL = [ ("text1",2,3,-1), ("text2",-1,5,6), ("text2",-1,5,-1) ] So simply remove N/A replace with -1. Do I need to read all lines? Data download shows N/A, its not a variable. LL is string Using ("text2",N/A,5,6) . Running python type on [0] is 'str'. Running python type on [1] , i get no output. If I split the line above as a, b,c,d, Since I want number not a N/A, is there a way to say if not

问题 In the function sqlPull() I pull the most recent 5 entries from a MySQL database every 5 seconds. In the second function dupCatch() I am attempting to remove duplicates that would in the n+1 SQL pull when compared to n. I want to save only the unique list of tuples, but right now the function is printing the same list of tuples 5 times every five seconds. In english what I am attempting to do with dupCatch() is take the data from sqlPull(), initialize and empty list and say for all of the

问题 Hi there I am having a small problem with a code I am trying to implement. I wish to convert a list of lists into a dictionary where the keys refer to the lists position in the original list of lists, and the values are a list of the items that were in said list (from the original list of lists). I also wish to remove all of the Nones present in the original list of lists. For example: [[(1, None), (2, None)], [(0, None), (2, None)], [(1, None), (0, None)]] I would want this to become: {0: [1

问题 This is part of a homework assignment. I've got several questions asking find the eid of the employee with the highest salary, or 2nd highest salary. Find the pilot that is certified for the most aircrafts. I don't have any idea on how to do it. There aren't any examples in the chapter, and google is proving less that helpful. If someone could show me how to do just one of these, it'll help a lot. here are the tables: Aircraft( aid : integer, aname : string, cruisingrange : integer )

问题 The other day I asked how could reduce a list of tuples by grouping one of the elements into arrays (F#: Reduce a list of tuples by grouping one of the elements into arrays). I wish now to learn how to do the opposite of this. Lets say I have this: ("A", ["B"; "C"; "D"; "E"]) and I want to get this: [("A", "B") ; ("A", "C") ; ("A" , "D") ; ("A" , "E")] What is the functional way to do this? How could I do it with a list of elements of this type to be appended? I have tried: let prb = ("A", [

问题 I am running MySQL query from python that returning tuple of dict, lets call it result. Now each dict has 3 key/value pairs as an element, one of these 3 element is date. Now I want to create "tuple of tuple of dict" something like (({},{},{}..),({},{},{}..),({},{},{}..)...) where each inner tuple represent the data of the same date. I know i can use dict comprehension. But am looking for more elegant way to do this. How can I do this in most efficient way ? 回答1: One good looking solution

问题 My code looks the following: from itertools import groupby for key, group in groupby(warnstufe2, lambda x: x[0]): for element in group: a = element[1:4] b = element[4:12] c = [a,b] print(c) When I print (c) I get something like this: [(a,b,c),(d,e,f)] [(g,h,i),(j,k,l)] where a1=(a,b,c) and b1=(d,e,f) and a2=(g,h,i) and b2 = (j,k,l). Of course there is a3... and b3... However, I need something like this: [(a,b,c),(d,e,f),(g,h,i),(j,k,l)] I already tried a for loop through c: for item in c:

问题 Why is it that when I run this console app: static void Main(string[] args) { var items = new List<(string login, string email)>(); items.Add(("james", "lsdkjsdkj@skdfjd.dfkd")); items.Add(("james2", "lsdkjsdkj@df333.dfkd")); items.Add(("james", "lsdkjsdkj@skdfjd.dfkd")); items.Add(("james2", "lsdkjsdkj@df333.dfkd")); foreach (var item in items) { Console.WriteLine(item.email); } var duplicates = items.Where(e => e.login == "james"); Console.WriteLine(duplicates.Count()); foreach (var

问题 NOTE: I edited the question! I am having trouble with iteration in Python, especially when I would like to sum up values up to a certain number. Here's more information on the problem I'm facing: I have a list of tuples that looks like this: [(1, 0.5, 'min'), (2, 3, 'NA'), (3, 6, 'NA'), (4, 40, 'NA'), (5, 90, 'NA'), (6, 130.8, 'max'), (7, 129, 'NA'), (8, 111, 'NA'), (9, 8, 'NA'), (10, 9, 'NA'), (11, 0.01, 'min'), (12, 9, 'NA'), (13, 40, 'NA'), (14, 90, 'NA'), (15, 130.1, 'max'), (16, 112, 'NA