indexing

问题 I read that NaNs are problematic, but the following causes an actual corruption of my data, rather than an error. Is this a bug? Have I missed something basic in the documentation? I would like the second command to give an error or to give the same response as the first command: ipdb> df year PRuid QC data 18 2007 nonQC 0 8.014261 19 2008 nonQC 0 7.859152 20 2010 nonQC 0 7.468260 21 1985 10 NaN 0.861403 22 1985 11 NaN 0.878531 23 1985 12 NaN 0.842704 24 1985 13 NaN 0.785877 25 1985 24 1 0

问题 I have a list of lists that looks like this: [[0], [0, 1, 2], [2], [3], [4], [5], [0, 1, 2, 3, 4, 5, 6, 7], [7], [8], [9], [8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18], [11], [11, 12, 13, 14, 15, 16, 17, 18], [13], [14], [14, 15, 16, 17, 18], [16, 17, 18], [17], [17, 18]] I am trying to find the least number of items in the list, when concatenated, that equal the full range of the list. In this case, the full range of the list is this: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,

问题 I asked this question and I got an answer which works for a general case with sequential and non missing data but not for my case specifically. I have a DF that looks as follows. eventTime MeteredEnergy Demand RunningHoursLamps 6/7/2018 0:00 67.728 64 1037.82 6/7/2018 1:00 67.793 64 1038.82 6/7/2018 2:00 67.857 64 1039.82 6/7/2018 3:00 67.922 64 1040.82 6/7/2018 4:00 67.987 64 1041.82 6/7/2018 5:00 64 1042.82 6/7/2018 6:00 1043.43 6/7/2018 23:00 68.288 6/8/2018 0:00 67.728 64 1037.82 6/8/2018

问题 So I have a typical find().sort() query that I run on my mongo collection. db.collection.find({field1:1}).sort({field2:1}) Now, say I have three indexes on this collection: single index on field1 single index on field2 compound index on field1 and field2 - {field1:1,field2:1} Now my question, how does mongoDB treat the above query? What are the indexes that will be used in a query like that- two single indexes or the one compound index? If I remove the compound index, does it in fact make use

问题 I am trying to understand numpy's combined slicing and indexing concept, however I am not sure how to correctly get the below results from numpy's output (by hand so that we can understand how numpy process combined slicing and indexing, which one will be process first?): >>> import numpy as np >>> a=np.arange(12).reshape(3,4) >>> a array([[ 0, 1, 2, 3], [ 4, 5, 6, 7], [ 8, 9, 10, 11]]) >>> i=np.array([[0,1],[2,2]]) >>> a[i,:] array([[[ 0, 1, 2, 3], [ 4, 5, 6, 7]], [[ 8, 9, 10, 11], [ 8, 9,

问题 I have to write small sections of code for an introductory programming class I'm taking - I had no trouble until I tried this one. The code works fine so far as I can tell but I keep getting the IndexError, can anyone tell me what I'm missing? vowel = {"a", "e", "o", "i", "u", "A", "E", "I", "O", "U"} word = input("Enter a phrase: ") if word[0] in vowel: print("an", word) else: print("a", word) EDIT: The code's working perfectly now, all I needed was the additional if statement for an empty

问题 In indexedDB, if the keys are arrays of integers such as [n,0] through [n,m] , for operations that involve getting all the records in which the first element of the array key is n or opening a cursor on the same set of records, is there any advantage to using an index on an additonal property that stores n over using a key range? Reasons to think an index may not be better include that the browser has to maintain the index for each change to the object store, an additional property has to be

问题 I have a huge email dump that I am trying to store and query in MongoDB. There are 1.6M emails, each of which is stored as the output from a Node module that parses raw emails into nice Javascript objects, like so: { "text" : "This is the text of my email", "subject" : "Great opportunity", "from" : [ { "address" : "chris.wilson@example.com", "name" : "Chris Wilson" } ], "to" : [ { "address" : "person.a@example.com", "name" : "Person A" }, { "address" : "person.b@example.com", "name" : "Person

问题 I am having this weird behavior in mysql 5.6 with full text indexes I am trying to search a patients database and get the exact matches first then partials by score with a Min Score so i don't return 100000+ results just some suggestions to prevent duplicates into a EHR type of app The problem is that the exact and partial matches have the same score... Is that an expected behavior? what options do I have? 回答1: You stated that you had the same score for exact matches and partials, but your

问题 Hello all I am trying to make an easy json with some data i pull from a type of API. I want the "key" to be one of the ids, however i get the following error "cannot fit 'int' into an index-sized integer". So looking around I think this means that the number I am trying to associate as the key is larger than a number can be?? So I was thinking about some possible work-arounds for this and was wondering if anyone knows a way to get around this. The best thing I can think of is create a