logo
down
shadow

How to stream a csv file with header to a HashMap<String, Double> in Java?


How to stream a csv file with header to a HashMap<String, Double> in Java?

Content Index :

How to stream a csv file with header to a HashMap<String, Double> in Java?
Tag : java , By : Igor Carron
Date : November 28 2020, 04:01 AM

I wish did fix the issue. I'm not going to give you the entire solution but here is a way to approach this problem,
Steps:
private void convertCsvtoMap(final String filePath) {
    try (Scanner in = new Scanner(new File(filePath))) {
        String line = null;
        Map<String, Double> resMap = new HashMap<>();
        while (in.hasNextLine()) {
            line = in.readLine();
            String[] fields = line.split(",");
            String key = fields[0].trim() + "|" + fields[1].trim() + ...;
            double value = Double.parseDouble(fields[5].trim());
            resMap.put(key, value);
        }
    } catch (Exception ex) {
        /* Handle Exception */
    }
}

Comments
No Comments Right Now !

Boards Message :
You Must Login Or Sign Up to Add Your Comments .

Share : facebook icon twitter icon

How to Convert Stream Stream<HashMap<String, Object>> to HashMap Array HashMap<String, Object>[]?


Tag : java , By : Saul
Date : March 29 2020, 07:55 AM
should help you out The following should work. Unfortunately, you have to suppress the unchecked warning.
@SuppressWarnings("unchecked")
HashMap<String, Object>[] arr = imagesStream.toArray(HashMap[]::new);
@SuppressWarnings({"unchecked", "rawtypes"})
HashMap<String, Object>[] array = stream.toArray(n -> new HashMap[n]);
@SuppressWarnings({"unchecked", "rawtypes"})
HashMap<String, Object>[] array = stream.toArray(new IntFunction<HashMap[]>() {
    public HashMap[] apply(int n) {
        return new HashMap[n];
    }
});

Compare HashMap<String, Double> and List<ArrayList<String>> in Java


Tag : java , By : cautionsign
Date : March 29 2020, 07:55 AM
it should still fix some issue I have a HashMap like arr1[]-{AA=0.05, BB=0.031, CC=0.056} and List> like arr2[]-[ [AA,BB,CC] , [BB, CC] , [AA, CC]]. I want to take output like List>.It will be [ [0.05,0.031,0.056] , [0.031, 0.056] , [0.05, 0.056]]. I used , , Here you go:
Map<String, Double> mappings = //get mappings
List<ArrayList<String>> source = //get source
List<ArrayList<Double>> target = new ArrayList<>();
for(ArrayList<String> sourceElement : source){
    ArrayList<Double> targetElememt = new ArrayList<>();
    for(String sourceElementString : sourceElement){
        targetElememt.add(mappings.get(sourceElementString));
    }
    target.add(targetElememt);
}
System.out.println(target);

Replace String With hashmap value using java 8 stream


Tag : java , By : Hans-Inge
Date : March 29 2020, 07:55 AM
seems to work fine As this cannot be made using only forEach() (message must be effectively final), workaround could be to create a final container (e. g. List) which stores a single String that is re-written:
final List<String> msg = Arrays.asList("helloABC");
map.forEach((key, value) -> msg.set(0, msg.get(0).replace(key, value)));
String test = msg.get(0);
String test = map.entrySet()
                 .stream()
                 .reduce("helloABC", 
                         (s, e) -> s.replace(e.getKey(), e.getValue()), 
                         (s1, s2) -> null);

Set of String with Stream to HashMap in Java 8


Tag : java , By : Sebastian Gift
Date : March 29 2020, 07:55 AM
To fix this issue You don't need the map() step. The logic that produces a List from a String should be passed to Collectors.toMap():
Map<String, List<String>> map = 
    mySet.stream()
         .collect(Collectors.toMap(Function.identity(),
                                   string -> {
                                       // put logic that returns List<String> here
                                   }));

Java 8 stream HashMap<String, ArrayList<String>> to SortedMap<String, Integer>


Tag : java , By : Mahyar Sepehr
Date : March 29 2020, 07:55 AM
may help you . I have HashMap> professions, and I want to create a SortedMap where the first entry is a string same to the first entry of the hashmap, and second entry is an Integer equal to the size of the ArrayList in the first map corresponding to the string. I also want that the sortedMap is sorted by the first entry (the string). , You're looking for the toMap collector as opposed to the groupingBy:
Map<String, Integer> resultSet = 
     professions.entrySet()
                .stream()
                .collect(Collectors.toMap(Map.Entry::getKey,
                        e -> e.getValue().size(),
                        (left, right) -> left, TreeMap::new));
Related Posts Related QUESTIONS :
  • Empty stack with one recursive method and one iterative method
  • What's the behavior of onBackpressureBuffer in RxJava2
  • Java regex can only use 1 quantifier in a lookback (need 2)
  • How to fix error in native query : it is showing syntax error near or at
  • How to retrieve nested object from a document and display it in FirestoreRecyclerOptions?
  • Why not use ListIterator for full LinkedList Operation?
  • Android Webview EvaluateJavascript sometimes does not return a response
  • Matcher java doesn't work but regex seems to be good
  • Finding dimensions of a .gif file
  • Java Number format how to change +/- sign to custom text
  • Entity partially saved when using JOINED inheritance strategy and setting spring.jpa.properties.hibernate.jdbc.batch_siz
  • Stored Procedure in Java Spring Boot Project returns null as Output
  • How to solve org.hibernate.MappingException which is causing due to inheriting a class
  • Clean Archtecture. Understanding of scheme
  • Processing 3 triangle not showing in Javafx 8 Window tab
  • How to specify a sequence-based generated value in Hibernate 5 via legacy mapping
  • Spring-boot application not getting auto-deployed on startup
  • How to only pass strings that the user select
  • Is there a way to SELECT using "GREATEST(field1, field2)" where field1 and field2 are aggregate sums in the sa
  • How to handle JSON objects wrapped into one JSON object with retrofit2?
  • Configure Hazelcast CPSubsystem Retries Timeout
  • how to use onBindViewHolder with multiple items in android RecyclerView
  • No ParameterResolver registered for parameter in BeforeAll method
  • Finding the path in a graph with the least casualties according to the lanchester square law
  • MongoWriteException when inserting into Mongodb with composite custom _id
  • Fetch Oracle procedure metadata with Java when multiple procedure signatures
  • Value modification of key-pair in HashMap and impact for a HashCode
  • Migration from solrj to spring-data-solr
  • How to check if you're still connected to the database with jpa
  • Use Date type in the graphql scheme
  • Split and add the string based on length
  • Is "main" method of spring boot application required when deploy as war
  • Getting the average within specific numbers in an array
  • how to use izpack to make my jar application to installer?
  • What is meant by src in Java Eclipse?
  • Create a mirrored linked list in Java
  • Examples of good JPA Java Desktop Application
  • Translate Java to Python -- signing strings with PEM certificate files
  • Algorithm Analysis tool for java
  • Java serial comm API - what does inputstream.read() return if a timeout occurs?
  • How do I make a background thread in Java that allows the main application to exit completely? This works in Linux, but
  • How to add an image dynamically at runtime in java
  • Java App on Mac asking for allow network connections everytime
  • Best actively maintained Java XMPP Library?
  • Multi-Threaded Application - Help with some pseudo code!
  • Scoping a StringBuilder inside a for loop
  • How to specify hash algorithm when updating LDAP via Java?
  • Class not found exception (org.apache.openjpa.enhance.PersistenceCapable) thrown in a client of WLS 10
  • In Java ,where in memory are class functions put?
  • How do I test expectedExceptionsMessageRegExp (exception message) using TestNG?
  • Help In understanding Multi Dimentional Arrays
  • No bean named '...' is defined and Spring @Resource annotation
  • Singleton design pattern vs Singleton beans in Spring container
  • flashvars object was not working in mozilla browser
  • Shell script to import mysql dump file
  • What are the best practices to separate data from users
  • May I use com.google.code prefix for my packages?
  • How to set classpath in manifest file , while creating JAR from eclipse?
  • dealing with voice in java
  • Error: java.security.AccessControlException: Access denied
  • shadow
    Privacy Policy - Terms - Contact Us © scrbit.com