collect

问题 I'm having a hard time collecting data from two distinct sources and merge the collections so that the final one is a set of objects ordered by 'dateCreated'. Context Users can ask questions in groups. A question can be either general or related to a specific video-game. If the question asked in a group is video-game related, this question also appears in the video-game's questions page. Currently, I have two general questions and one specific to one video-game. Hence, when fetching the

问题 I'm porting a piece of code from .NET to Java and stumbled upon a scenario where I want to use stream to map & reduce. class Content { private String propA, propB, propC; Content(String a, String b, String c) { propA = a; propB = b; propC = c; } public String getA() { return propA; } public String getB() { return propB; } public String getC() { return propC; } } List<Content> contentList = new ArrayList(); contentList.add(new Content("A1", "B1", "C1")); contentList.add(new Content("A2", "B2",

问题 Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production. I have a table in the below format. Name Department Johny Dep1 Jacky Dep2 Ramu Dep1 I need an output in the below format. Dep1 - Johny,Ramu Dep2 - Jacky I have tried the 'LISTAGG' function, but there is a hard limit of 4000 characters. Since my db table is huge, this cannot be used in the app. The other option is to use the SELECT CAST(COLLECT(Name) But my framework allows me to execute only select queries and no PL

问题 My question is, how can I find all array indexes by a word ? [ {name: "Jeff Crawford", tel: "57285"}, {name: "Jeff Maier", tel: "52141"}, {name: "Tim Maier", tel: "73246"} ] If I search for "Jeff", I want to get: [ {name: "Jeff Crawford", tel: "57285"}, {name: "Jeff Maier", tel: "52141"}, ] 回答1: To make it more versatile, you could take a function which takes an array of objects, the wanted key and the search string, wich is later used as lower case string. function find(array, key, value) {

问题 According to the accepted answer in pyspark collect_set or collect_list with groupby, when you do a collect_list on a certain column, the null values in this column are removed. I have checked and this is true. But in my case, I need to keep the null columns -- How can I achieve this? I did not find any info on this kind of a variant of collect_list function. Background context to explain why I want nulls: I have a dataframe df as below: cId | eId | amount | city 1 | 2 | 20.0 | Paris 1 | 2 |

问题 This question already has answers here : Closed 8 years ago . Possible Duplicate: How do I get the nth element from a Dictionary? If there's a Dictionary with total of Y items and we need N th item when N < Y then how to achieve this? Example: Dictionary<int, string> items = new Dictionary<int, string>(); items.add(2, "Bob"); items.add(5, "Joe"); items.add(9, "Eve"); // We have 3 items in the dictionary. // How to retrieve the second one without knowing the Key? string item = GetNthItem(items

问题 I have an array of hashes as per below. Say my array is @fruits_list: [ {:key_1=>15, :key_2=>"Apple"}, {:key_1=>16, :key_2 =>"Orange"}, {:key_1=>17, :key_2 =>" "} ] I want to join the values in the hash using a '|'; but my final output should not contain the nil value. I connect it using: @fruits_list.collect { |hsh| hsh[:key_2] }.join("|") But this adds nil in my output, so my final output has 3 items {"Apple" | "Orange" | " "}. I want 2 items in my list and would like to eliminate the nil

问题 I tought that List is enough but I need to add element to my list. I've tried to put this in ListBuffer constructor but without result. var leavesValues: ListBuffer[Double] = leaves .collect { case leaf: Leaf => leaf.value.toDouble } .toList Later on I'm going to add value to my list so my expected output is mutable list. Solution of Raman Mishra But what if I need to append single value to the end of leavesValues I can reverse but it's not good enough I can use ListBuffer like below but I

问题 stateDF .withWatermark("t","1 seconds") .groupBy(window($"t","1 minutes","1 minutes"),$"hid") .agg(collect_list("id")) .writeStream.outputMode("append") .format("console").trigger(ProcessingTime("1 minutes")) .start().awaitTermination() When I add 'collect_list', I'll have this problem. But by spark core it can be done. ERROR： java.lang.RuntimeException: Collect cannot be used in partial aggregations. at scala.sys.package$.error(package.scala:27) at ... java.util.concurrent.ThreadPoolExecutor

问题 I have two data frames: df1 +---+-----------------+ |id1| items1| +---+-----------------+ | 0| [B, C, D, E]| | 1| [E, A, C]| | 2| [F, A, E, B]| | 3| [E, G, A]| | 4| [A, C, E, B, D]| +---+-----------------+ and df2 : +---+-----------------+ |id2| items2| +---+-----------------+ |001| [A, C]| |002| [D]| |003| [E, A, B]| |004| [B, D, C]| |005| [F, B]| |006| [G, E]| +---+-----------------+ I would like to create an indicator vector (in a new column result_array in df1 ) based on values in items2