How to split strings and store into a hashmap of strings in java

Question

I want to split below string

G04:AMPARAMS|DCode=50|XSize=66mil|YSize=66mil|CornerRadius=0mil|HoleSize=0mil|Usage=FLASHONLY|Rotation=0.000|XOffset=0mil|YOffset=0mil|HoleType=Round|Shape=Octagon|*

I was first spliting the code from '|' pipe sign then spliting again from '=' equal sign but problem i am facing here is that how to store the value in hashmap as they are in a loop so i can't store it in a hashmap. Any Possible solution would be appricated.

String[] temp=line.split("\\|");
for(String p:temp){
    HashMap<String,String>attributes=new HashMap<String,String>();
    String[] key =p.split("\\=");

    for(String tmp:key){
    //System.out.println(tmp);
    attributes.put();
    }

Oleg Cherednik · Accepted Answer · 2018-12-13 11:58:42Z

4

No Streams:

public static Map<String, String> split(String str) {
    final Pattern sep = Pattern.compile("\\s*\\|\\s*");
    final Pattern eqSep = Pattern.compile("(?<key>[^=\\s]+)\\s*=\\s*(?<value>[^=]+)");

    Map<String, String> map = new HashMap<>();

    for (String part : sep.split(str)) {
        Matcher matcher = eqSep.matcher(part);

        if (matcher.matches())
            map.put(matcher.group("key"), matcher.group("value"));
    }

    return map;
}

With Streams:

public static Map<String, String> split(String str) {
    final Pattern sep = Pattern.compile("\\s*\\|\\s*");
    final Pattern eqSep = Pattern.compile("(?<key>[^=\\s]+)\\s*=\\s*(?<value>[^=]+)");

    return sep.splitAsStream(str)
              .map(eqSep::matcher)
              .filter(Matcher::matches)
              .collect(Collectors.toMap(matcher -> matcher.group("key"), matcher -> matcher.group("value")));
}

edited Dec 13, 2018 at 11:58

answered Dec 13, 2018 at 11:54

Oleg Cherednik

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Comments

Ousmane D. · Accepted Answer · 2018-12-13 12:03:46Z

3

This is easier done via streams:

Arrays.stream(input.split("\\|"))
      .map(s -> s.split("="))
      .filter(a -> a.length == 2)
      .collect(toMap(a -> a[0], a -> a[1], (l, r) -> r, HashMap::new));

Arrays.stream create a Stream<String> which we can then further refine our query via several built-in stream API methods.
map splits each string on "=" therefore returns a Stream<String[]>
filter retains the array elements that have exactly two elements
finally, we supply a toMap collector to the collect method to build the Map<String, String>

edited Dec 13, 2018 at 12:03

answered Dec 13, 2018 at 11:26

Ousmane D.

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2 Comments

DodgyCodeException Over a year ago

It may be worth adding that the OP specifically asked for a HashMap, but toMap creates a map of unspecified nature.

Anton Balaniuc Over a year ago

to avoid creating an intermediate array it is better to use Pattern.compile.splitAsStream which returns stream directly: Pattern.complile("\\|").splitAsStream(input)

Eran · Accepted Answer · 2018-12-13 11:26:00Z

1

Looks like what you need is:

String[] temp = line.split("\\|");
Map<String,String> attributes = new HashMap<String,String>();
for (String p : temp) {
    String[] key = p.split("\\=");
    if (key.length == 2) {
        attributes.put(key[0],key[1]);
    }
}

Note that you should create a single HashMap outside the loop, since you want to store all the key-value pairs in the same HashMap.

answered Dec 13, 2018 at 11:26

Eran

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