multimap

How can I compare two MultiMaps?

梦想的初衷 提交于 2019-12-07 02:10:32
问题 I have two Multimaps which have been created from two huge CSV files. Multimap<String, SomeClassObject> mapOne = ArrayListMultimap.create(); Multimap<String, SomeClassObject> mapTwo = ArrayListMultimap.create(); I have assumed one CSV column to be as a Key and each of the Key has thousands of values associated with it. Data contained within these Multimap s should be same. Now I want to compare the data within these Multimap s and find if any values are different. Here are the two approaches

Combine two Maps into a MultiMap

我只是一个虾纸丫 提交于 2019-12-06 18:38:15
问题 What is the best way to combine two Maps into a single Guava MultiMap in Java? For example: Map1 contains (1, a) and (2, b) Map2 contains (2, c) and (3, d) Then the resulting combined multimap would contain (1, {a}), (2, {b, c}), and (3, {d}) This is my current solution: Multimap<T, K> combineMaps(Map<T, K> map1, Map<T, K> map2) { Multimap<T, K> multimap = new MultiMap(); for (final Map.Entry<T, K> entry : map1.entrySet()) { multimap.put(entry.getKey(), entry.getValue()); } for (final Map

How to stream a map with collection using Java 8 streams?

孤街浪徒 提交于 2019-12-06 16:29:30
问题 I'd like to stream a map with collection using Java 8 streams. For example, having the following data: Map<String, Collection<Integer>> data; I'd like to go over the elements handling each integer value with the corresponding key strings. For example: data.keyValueStream((k,v)-> ...) Any idea how to achieve this? Thanks. * Regarding the question "Why do you need it?", it could be a bunch of reasons and I'm not sure it's important. Anyhow, I'll "flow" with you... My specific scenario is to

Google Maps API v2 multiple map fragment problems

回眸只為那壹抹淺笑 提交于 2019-12-06 16:02:41
I have experimented few issue with the new google map api v2 I have a fragment that wraps a mapFragment, this is created at the begging of the app. The in another fragment that is created when the user click on a button, this content an other mapFragment. But this map is showing the first map that is showing on the first fragment. An also it get frozen and can't make actions on it... I've read that some users have problems to show multimaps. Any idea how can I solve this? This is how I create the maps: mMapFragment = (SupportMapFragment) this.getActivity().getSupportFragmentManager()

Spark - Can a MultiMap be converted to a DataFrame in JAVA

纵然是瞬间 提交于 2019-12-06 14:52:17
I'm trying to convert a MultiMap of billions of data values to a Spark DataFrame to run calculations on then write the results to a cassandra table. I generate the multimap from the following cassandra query and loop. I'd be happy to take suggestions if there would be a better way to get and manipulate this data into a DataFrame like I am with the loop. Code Updated With Answer: //Build ResultSet from cassandra query for data manipulation. Statement stmt = new SimpleStatement("SELECT \"Power\",\"Bandwidth\",\"Start_Frequency\" FROM \"SB1000_49552019\".\"Measured_Value\";"); //Statement stmt =

Does `std::multimap` guarantee actual value of each key in equal range?

爱⌒轻易说出口 提交于 2019-12-06 11:00:23
C++ standard for "26.4.5.1 Class template multimap overview" p1 says: A multimap is an associative container that supports equivalent keys (possibly containing multiple copies of the same key value ) and provides for fast retrieval of values of another type T based on the keys. emphasis is mine. So does it mean that std::multimap may not keep a copy of original key object when inserted into equal range and replace it with equal one? PS To make clear this question is inspired by this Does Each Element of a multimap Contain Both the Key and Value? and I want to know if multimap allowed to do

Sorting the data in increasing order based on keys in Multimap Google Guava

血红的双手。 提交于 2019-12-06 03:30:46
I created a Multimap Multimap<Integer, String> mhm= ArrayListMultimap.create(); my numbers range from 0 to 2400. I have inserted data like mhm.put(800 ,"A") mhm.put(1200 ,"B") mhm.put(1200 ,"A") mhm.put(1500 ,"B") mhm.put(600 ,"A") mhm.put(700 ,"B") mhm.put(1200 ,"A") mhm.put(1201 ,"B") I want to sort the Multimap on key field that is Integer? There are not much posts on satckoverflow which tells how to do this. expected output: mhm.put(600 ,"A") mhm.put(700 ,"B") mhm.put(800 ,"A") mhm.put(1200 ,"B") mhm.put(1200 ,"A") mhm.put(1200 ,"A") mhm.put(1201 ,"A") mhm.put(1500 ,"B") Please note that

Dictionary class

久未见 提交于 2019-12-05 18:23:14
Is it possible to have multiple values, for a single key, in the Java dictionary class? First, regarding the dictionary class: That class is considered obselete, the documentation recommends using Map instead. This kind of collection you are seeking is called a multimap. You could implement one yourself with a list, but that is tedious. You may want to use a MultiMap from either Apache Collections or from the Google Collections. While I am personally a fan of the apache collections, they do not really support generics, so a Google multimap may be safer. Sure. Use a list as the value. You

Java Guava combination of Multimap and Cache

可紊 提交于 2019-12-05 13:11:42
问题 Is there any such thing as a combination of Guava's Cache and Multimap functionality available? Essentially, I need a collection where entries expire after a given time such as available in Cache but I have non-unique keys and I need the entries to expire independently. 回答1: I think that Louis Wasserman provided the answer in one of the comments above, i.e. that there is no off-the-shelf combo of Multimap and Cache available. I have solved my problem/requirements with the solution outlined in

How can I compare two MultiMaps?

我是研究僧i 提交于 2019-12-05 09:27:35
I have two Multimaps which have been created from two huge CSV files. Multimap<String, SomeClassObject> mapOne = ArrayListMultimap.create(); Multimap<String, SomeClassObject> mapTwo = ArrayListMultimap.create(); I have assumed one CSV column to be as a Key and each of the Key has thousands of values associated with it. Data contained within these Multimap s should be same. Now I want to compare the data within these Multimap s and find if any values are different. Here are the two approaches I am thinking of: Approach One: Make one big list from the Multimap . This big list will contain a few