Which Algorithm should i use here? Finding Strings in a String Array

Question

I have 2 Arrays.

One Array has Strings, which i look for.

static String[] namesToLookFor = { "NR", "STAFFELNR", "VONDATUM"};

the otherArray has Strings, which i got from a *.csv file.

indexString = indexReader.readLine();
indexArray = indexString.split(";");

My Goal is to system.out.println() the Values which are the indexArray[] and NOT in the namesToLookFor[].

For example:

namesToLookFor = {"NR"};

indexArray = {"HELLO","NR"};


//Any Algorithm here...

So in this case"HELLO" should be printed out, since it is NOT in the namesToLookFor[] Array.

I'd suggest using a Set rather than an array, then you can difference the set objects — OneCricketeer
– OneCricketeer, Commented Jul 9, 2018 at 13:23

Youcef LAIDANI · Accepted Answer · 2018-07-09 13:31:35Z

5

If you are using java8 you can do the following

List<String> list = Arrays.asList(namesToLookFor);
Arrays.stream(indexArray)
        .filter(item -> !list.contains(item))
        .forEach(System.out::println);

edited Jul 9, 2018 at 13:31

Youcef LAIDANI

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answered Jul 9, 2018 at 13:28

Parth Pandya

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Comments

T A · Accepted Answer · 2018-07-09 13:57:36Z

1

You could iterate over your indexArray and check for each element if its contained in your namesToLookFor Array:

    String[] namesToLookFor = {"NR"};

    String[] indexArray = {"HELLO","NR"};

    List<String> excludedNames = Arrays.asList(namesToLookFor);

    for(String s : indexArray) {
        if (!excludedNames.contains(s)) {
            System.out.println(s);
        }
    }

Will output only "HELLO".

edited Jul 9, 2018 at 13:57

answered Jul 9, 2018 at 13:26

T A

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1 Comment

alaster Over a year ago

Arrays.asList(namesToLookFor) inside loop will create many unwanted objects. You should place it before loop and reuse

alaster · Accepted Answer · 2018-07-10 12:42:13Z

1

// Put array into set for better performance
Set<String> namesToFilter = new HashSet<>(Arrays.asList("NR", "STAFFELNR"));
String[] indexArray = indexReader.readLine().split(";");

// Create list with unfiltered values and remove unwanted ones
List<String> resultList = new ArrayList<>(indexArray);
resultList.removeAll(namesToFilter);

// Do with result whatever you want
for (String s : resultList)
    System.out.println(s);

edited Jul 10, 2018 at 12:42

answered Jul 9, 2018 at 13:49

alaster

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Comments

Riggy · Accepted Answer · 2018-07-09 16:44:29Z

0

With Array you can use contains function but after converting it to be ArrayList, the contains function will check if the ArrayList contains a specific value.

for (int i =0; i<indexArray.length; i++) {
        if (!Arrays.asList(namesToLookFor).contains(indexArray[i])) 
            System.out.println(indexArray[i]);
    }

edited Jul 9, 2018 at 16:44

Riggy

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answered Jul 9, 2018 at 15:16

Anhaar Ali

1

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