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Adding key value pairs from a file to a Hashmap


Adding key value pairs from a file to a Hashmap

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Adding key value pairs from a file to a Hashmap
Tag : java , By : Ted Leung
Date : January 11 2021, 03:34 PM

it fixes the issue First let's take a look at why your solution does not give intended result. When you split each line around the delimiter : then there may be many key value pairs. But you just consider the first key value pair while omitting the rest. So this works for the last line in your example since it has only one corresponding map entry. At the same time it does not work for the first line since it has many corresponding map entries while you are treating only the first entry.
And here's my approach for solving this problem. Take each line in your file and split it around the delimiter :. This yields an array to each corresponding line. Since every line has a trailing : character, you have to skip the relevant last element in the array. Then each even indice in the array becomes the key in the map, and the immediately following odd index becomes the corresponding value. Here's how it looks.
private static final Pattern DELIMITER = Pattern.compile(":");
Map<String, String> activityMap = lines.map(DELIMITER::split)
    .flatMap(a -> IntStream.range(0, a.length - 1).filter(i -> i % 2 == 0)
        .mapToObj(i -> new AbstractMap.SimpleEntry<>(a[i], a[i + 1])))
    .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (a, b) -> a));

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Adding key-value pairs in a plist file programmatically preserving the existing order of the file


Tag : objective-c , By : kakashi_
Date : March 29 2020, 07:55 AM
I wish did fix the issue. To do this, you will need to write your own plist parser and generator. For full flexibility, you’ll need to write it from scratch, not relying on an XML parser, or at least not a general-purpose one.

Adding values from a text file into a HashMap


Tag : java , By : Alan Little
Date : March 29 2020, 07:55 AM
wish of those help Use HashMap inbuit function put to insert keys into the HashMap and use get function to get the value of any particular key inserted into the HashMap.
        HashMap<String,String[]> map = new HashMap<>();
        //write code for taking input from file into string arrays
        for(int i = 0; i < numOfRows; i++){
            for(int j = 0; j < 4; j++){
                map.put(weather[i], condition[i][j]);
            }
        }

Java Hashmap -- Key Value Pairs from Stdin to HashMap


Tag : java , By : al.
Date : March 29 2020, 07:55 AM
hop of those help? Not really sure how you want to add them, as int's or Strings, but remember they have to be Objects.
class Inp {
    public void scan() {
        Scanner sc = new Scanner(System.in);

        HashMap<Integer,Integer> map = new HashMap<Integer,Integer>();
        while (true) {
            String sr = sc.nextLine();
            String[] tk = sr.split(" ");
            Integer key = 0, value = 0;
            try {
                key = Integer.parseInt(tk[0]);
                value = Integer.parseInt(tk[1]);
            }
            catch (NumberFormatException e) {
                break;
            }
            map.put(key,value);
        }

    }

    public static void main(String[] args) {
       Inp inp = new Inp();
       inp.scan();

    }
}

Adding values from a file to a HashMap with a Map inside


Tag : java , By : ussballantyne
Date : March 29 2020, 07:55 AM
fixed the issue. Will look into that further First you need to check if the nested map exists and if not, create it. Then you can add the value by retrieving the nested map and putting an object inside of that map. eg:
if (!girlsByYear.containsKey(number)) {
    girlsByYear.put(number, new HashMap<>());
}
girlsByYear.get(number).put(name, value);

Hashmap problem adding strings from a file in Java


Tag : java , By : barefootChild
Date : March 29 2020, 07:55 AM
help you fix your problem I have a problem adding strings into hashmap in java. My file has inside the following , Base on new information provided in comments.
Given a
 Map<String, Integer> map = new HashMap<>();
        int mapcounter = 0;
        String line = filemap.nextLine();
        while(filemap.hasNextLine()) {
            if(!line.startsWith("#")) {

               // split the two node column into two values.
                String[] words = line.split("\\s+");

                if(!map.containsKey(word[0])){
                    map.put(word[0],mapcounter++);
                }
                if(!map.containsKey(word[1])){
                    map.put(word[1],mapcounter++);
                }
            }
            line = filemap.nextLine();
        }
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