CODEWITHSUNDEEP
javahashmaplinkedhashmap
Prabu
Prabu

Reputation: 3728

Java Linked HashMap with ArrayList empty checking

How to check wheather specific kay have an empty value in a LinkedhashMap

Map<String,List<String>>resultTable = new LinkedHashMap<String, List<String>>();

following are the resultTable

Key = Sr.ID and values are {660316, 660320, 590089, 661725, 661865, 661864, 661862, 660300} Key = Docket and values are {0150, 0150b1, 142747, 1725.186589, 2708.5, 2738.56, 45rdfg, 56t} Key = Rec No and values are{,8821893, , , , , , , }

how can we check if particular key (i.e Sr.ID or Docket or Rec No.)have an empty Value in the List (Rec No, Key have an Empty Value)

how can we check if particular key (i.e Sr.ID or Docket or Rec No.)don't have an empty Value in the List Docket Key Don't have an empty Value

Upvotes: 0

Views: 2706

Answers (3)

Mena
Mena

Reputation: 48404

Your values are of type List<String>.

To check that an element of the list is empty for any given key, you can simply:

// iterate map entries
for (String key: resultTable.keySet()) {
    // TODO null check!
    if (resultTable.get(key).contains("")) {
        // list has an empty element
        System.out.printf("Found an empty value for %s%n", key);
    }
}

Note

And here's a Java 8 syntax with a BiConsumer<String,List<String>> lambda:

resultTable.forEach(
    (s,l) -> {
        // TODO null check!
        if (l.contains("")) System.out.printf("Found an empty value for %s%n", s);
    }
);

Upvotes: 3

Fran Montero
Fran Montero

Reputation: 1680

This is a simple method for checking an empty value for a particular key:

private boolean checkEmptyVal(String key){

        boolean result = false;
        List<String> val = resultTable.get(key);

        if(val != null && val.contains("")) {
            result = true;              
        }

        return result;
    }

Upvotes: 2

Chop
Chop

Reputation: 4527

According to your example, an empty value is not a null but an empty string.

To check for an empty value in a list, you can do list.contains("").

Translated to your context, this is:

if (resultTable.get(key).contains("")) {
    // empty value here
}

Mena suggested checking for all keys one after the other:

// iterate map values
for (List<String> value: resultTable.values()) {
    if (value.contains("")) {
        // list has an empty element
    }
}

You can also add code to remove all empty values from a list:

while (list.remove("")) {
    log.debug("Empty value removed");
}

Upvotes: 0

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