collect

问题 I have a List and has to create Map from this for further use, I am using RDD, but with use of collect(), job is failing in cluster. Any help is appreciated. Please help. Below is the sample code from List to rdd.collect. I have to use this Map data further but how to use without collect? This code creates a Map from RDD (List) Data. List Format->(asdfg/1234/wert,asdf) //List Data to create Map val listData = methodToGetListData(ListData).toList //Creating RDD from above List val rdd =

问题 I am using Rails 3.2.2 and I would like to quote all array elements with ' and return a string containing all those quoted and comma-separated elements. At this time I am using ['a', 'b', 'c'].collect {|x| "'#{x}'"}.join(", ") # => "'a', 'b', 'c'" but I think I can improve the above code (maybe by using a unknown to me Ruby method, if it exists). Is it possible? 回答1: I use "'#{%w{a b c}.join("', '")}'" Here is expanded version: ' # Starting quote %w{a b c}.join("', '") # Join array with ', '

问题 I have defined a table type PL/SQL variable and added some data there. create or replace type varTableType as table of varchar2(32767); my_table varTableType := varTableType() ... my_table := some_function(); Now I have this my_table table type variable with several thousands of records. I have to select only those records ending with specific character, say 'a' and get results in a comma separated string. I think that COLLECT function could do this, but I do not understand exactly how. I am

问题 I'm trying to get the COLLECT function to work for me. I'm using 10g and therefore found that LISTAGG and WM_CONCAT will not work (invalid identifier errors). The data I have is for example as follows. Order Lot 123 A23088 123 A23089 089 AABBCC 305 120848 305 CCDDYY What I need returned is as follows Order Lot 123 A23088, A23089 089 AABBCC 305 120848, CCDDYY Using the following, I get the error: TO_STRING is an invalid identifier TO_STRING ( CAST(COLLECT(DISTINCT LOT) AS varchar2(100)) ) AS

问题 I'm trying to get the COLLECT function to work for me. I'm using 10g and therefore found that LISTAGG and WM_CONCAT will not work (invalid identifier errors). The data I have is for example as follows. Order Lot 123 A23088 123 A23089 089 AABBCC 305 120848 305 CCDDYY What I need returned is as follows Order Lot 123 A23088, A23089 089 AABBCC 305 120848, CCDDYY Using the following, I get the error: TO_STRING is an invalid identifier TO_STRING ( CAST(COLLECT(DISTINCT LOT) AS varchar2(100)) ) AS

问题 I have an array of hashes Eg: cars = [{:company => "Ford", :type => "SUV"}, {:company => "Honda", :type => "Sedan"}, {:company => "Toyota", :type => "Sedan"}] # i want to fetch all the companies of the cars cars.collect{|c| c[:company]} # => ["Ford", "Honda", "Toyota"] # i'm lazy and i want to do something like this cars.collect(&:company) # => undefined method `company' I was wondering if there is a similar shortcut to perform the above. 回答1: I believe your current code cars.collect{|c| c[

问题 I m using Java 8 for grouping by data. But results obtained are not in order formed. Map<GroupingKey, List<Object>> groupedResult = null; if (!CollectionUtils.isEmpty(groupByColumns)) { Map<String, Object> mapArr[] = new LinkedHashMap[mapList.size()]; if (!CollectionUtils.isEmpty(mapList)) { int count = 0; for (LinkedHashMap<String, Object> map : mapList) { mapArr[count++] = map; } } Stream<Map<String, Object>> people = Stream.of(mapArr); groupedResult = people .collect(Collectors.groupingBy

问题 I m using Java 8 for grouping by data. But results obtained are not in order formed. Map<GroupingKey, List<Object>> groupedResult = null; if (!CollectionUtils.isEmpty(groupByColumns)) { Map<String, Object> mapArr[] = new LinkedHashMap[mapList.size()]; if (!CollectionUtils.isEmpty(mapList)) { int count = 0; for (LinkedHashMap<String, Object> map : mapList) { mapArr[count++] = map; } } Stream<Map<String, Object>> people = Stream.of(mapArr); groupedResult = people .collect(Collectors.groupingBy

问题 I am trying to get following Map via Java 8 Class One { String one; List <Two> two; } Class Two { BigDecimal bd; } How do I collect a Map which contains grouping by One.one i.e., first parameter of map. For second parameter of map sum of Two.bd. 回答1: You can use this: List<One> list = ...; Map<String, BigDecimal> result1 = list.stream() .collect(Collectors.groupingBy(One::getOne, // key is One.one Collectors.mapping(one -> one.getTwo().stream() // get stream of One.two .map(Two::getBd) // map

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed last year . I need your advice to simplify this code below. I have a player list with an ID of the games won. I want to extract the 2 best players from this list (the 2 players who have a better amount of match Id) Once extracted, I have to return the initial list to do other operations. I think it is possible to improve this