String to Integer array conversion

Question

I need to add values into an int array.

    int[] placeHolders[];

Now i do not know the size of the elements to add into this array. I add it while i have input. I want to know how can i convert my string output values into int array repeatedly.

Input: 23.45.1.34

I am using string tokenize on . to get tokens

Value = Integer.parseInt(strtokObject.nextElement().toString());

I am using above line to add int to single int value but if i need to add int elements to array just like push in vector (C++ STL) i am unable to do.

in fact you can't push elements in java arrays, use Lists/ArrayLists instead. Also by using string.split(".") you'll get an array of strings representing your numbers — Carlo Moretti
– Carlo Moretti, Commented Sep 20, 2012 at 7:44

AlexR · Accepted Answer · 2012-09-20 07:44:28Z

5

String str = "23.45.1.34";
String sarr = str.split("\\.");
int[] result = new int[sarr.length];
for (int i = 0;  i < sarr.length;  i++) {
    result[i] = Integer.parseInt(s);
}

answered Sep 20, 2012 at 7:44

AlexR

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1 Comment

CodeMonkey Over a year ago

Using: ArrayList<Integer> placeHolders; int value = Integer.parseInt(strtokObject.nextElement().toString()); cageObject.placeHolders.add(value); Still getting errorsException: java.lang.NullPointerException

FThompson · Accepted Answer · 2012-09-20 07:45:25Z

2

When you don't know the size of a data set to be stored in an array, you should use an implementation of java.util.List<E> such as ArrayList.

ArrayList<Integer> placeHolderList = new ArrayList<Integer>();
int value = Integer.parseInt(strtokObject.nextElement().toString());
placeHolderList.add(value); // adds the int to the underlying array

You can then use List#toArray to convert your list into an array if necessary.

answered Sep 20, 2012 at 7:45

FThompson

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Comments

Vala · Accepted Answer · 2012-09-20 07:45:27Z

2

I'd use myString.split("\\.") to return a String[], create an equal size int[], then parse each String to an int rather than use a tokenizer. Also you could know the size of placeHolders by counting '.'s in the string (e.g., myString.replaceAll("[^\\.]", "").length()) (obviously add one to that number).

answered Sep 20, 2012 at 7:45

Vala

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Comments

Matin Kh · Accepted Answer · 2012-09-20 08:07:22Z

1

I assume your input string is input.

So you can do something like this:

String[] inputStrs = input.split("\\.");

and

//Do a while loop
placeholder[i] = Integer.ParseIne(inputStrs[i]);

edited Sep 20, 2012 at 8:07

answered Sep 20, 2012 at 7:46

Matin Kh

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1 Comment

Vala Over a year ago

Make sure you escape that '.' (\\.), otherwise you'll be splitting on EVERY character (String.split() takes a regular expression).

Vala · Accepted Answer · 2012-09-20 07:59:45Z

0

You can use ArrayList<Integer> which is similar to vector in c++. add to it using aList.add(num);

if you want an array you can at the end use the toArray method.

Integer[] arr = aList.toArray(new Integer[0]);

edited Sep 20, 2012 at 7:59

Vala

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answered Sep 20, 2012 at 7:47

meirrav

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