How to count how many times an item repeats in an Array with unknown size?

Question

How to count how many times an item repeats in an Array with unknown size?

Asked 10 years ago

Viewed 4,918 times

3

How to count how many times an item appears in an Array I don’t know the size of? The array was created from a . CSV.

Considered using a loop for(Object object : csv) instead of something for(int i = 0; i < csv.length; i++)?

– Renan Gomes

2014/11/11 at 01:02
1

If you have an array then you can get its size - just access the property length array - independent of how the array was created.

– carlosfigueira

2014/11/11 at 02:52
@user2296455 if the answer has solved your question let us know, if you do not also warn. :)

– João Neto

2014/11/14 at 02:45

2 answers

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by João Neto • **2,676** points · Answer 1 · 2014-11-11T03:25:06+00:00

I think you can do so, create a method and pass by parameter the Array and the Item to be checked, if it is a String Array for example:

public int contarRepeticoes(String[] array, String valor) {

    int contador = 0;

    if(array!=null) {
        for(int i=0; i<array.length(); i++) {
             if(array[i]!=null) {
                 if(array[i].equals(valor)) {
                      contador++;
                 }
             }
        }
    } else {
            System.out.println("Vetor nulo");
    }
    return contador;
}

I think something like this works, no IDE here to test.

by Rodrigo Guedes • **327** points · Answer 2 · 2014-11-11T09:40:19+00:00

The code below serves for any type of input data (String, int, double etc):

public static int contaArray(ArrayList<Object> array, Object valorProcurado){
    int contador = 0;
    if (array != null){
        for (Object item : array){
            if (item != null && item.equals(valorProcurado)){
                contador++;
            }
        }
    }
    return contador;
}