I'm new to the concept of arraylist. I've made a short program that is as follows:
It gives the output: Now my questions are:
asked May 7, 2012 at 6:26
2 First of all, for initializing a container you cannot use a primitive type
(i.e.
For adding elements, just use the
Last, but not least, for printing the
If you want to access the i element, where i is an index from 0 to the length of the array-1, you can do a :
I suggest reading first on Java Containers, before starting to work with them. answered May 7, 2012 at 6:34
Raul ReneRaul Rene 9,8639 gold badges52 silver badges75 bronze badges 0 More simple than that.
In the first line you create the object and in the constructor you pass an array parameter to List. In the second line you have all the methods of the List class: .get (...)
Wahib Ul Haq 4,0143 gold badges44 silver badges40 bronze badges answered Jun 15, 2017 at 11:03
1 answered May 7, 2012 at 6:28
truthealitytrutheality 22.6k6 gold badges51 silver badges67 bronze badges 1 The setup:
To retrieve a single int[] array in the ArrayList by index:
To retrieve all int[] arrays in the ArrayList:
Output formatting can be performed based on this logic. Goodluck!! answered Nov 30, 2017 at 15:50
mtebongmtebong 1111 silver badge3 bronze badges 3 In java, an array is an object. Therefore the call to arl.get(0) returns a primitive int[] object which appears as ascii in your call to System.out. The answer to your first question is therefore
If you're looking for particular elements, the returned int[] object must be referenced as such. The answer to your second question would be something like
answered May 7, 2012 at 6:37
EveryoneEveryone 2,3462 gold badges26 silver badges38 bronze badges You have to use
mayo 3,6851 gold badge35 silver badges42 bronze badges answered Oct 18, 2015 at 15:57
NourNour 1,4281 gold badge18 silver badges27 bronze badges 3 Everyone is right. You can't print an int[] object out directly, but there's also no need to not use an ArrayList of integer arrays. Using,
means splitting the String object into a substring if you want to insert anything in between, such as commas. Here's what I think amv was looking for from an int array viewpoint.
This answer is a little late for amv but still may be useful to others. answered Mar 31, 2014 at 22:45
clemens 16k11 gold badges45 silver badges62 bronze badges answered Aug 6, 2017 at 9:41
Rahul NaikRahul Naik 1051 silver badge8 bronze badges
Maddy 4,1154 gold badges32 silver badges53 bronze badges answered Sep 7, 2017 at 11:31
GIGOGIGO 689 bronze badges Integer is wrapper class and int is primitive data type.Always prefer using Integer in ArrayList. answered Jan 11, 2020 at 6:49
For the more inexperienced, I have decided to add an example to demonstrate how to input and output an ArrayList of Integer arrays based on this question here.
Thanks to this answer on this question here, I got the correct answer. I believe this satisfactorily answers OP's question, albeit a little late and can serve as an explanation for those with less experience. answered Jun 30, 2020 at 13:46
Anshuman KumarAnshuman Kumar 3621 gold badge5 silver badges19 bronze badges
This is one of the ways, you can initialize the fixed size ArrayList in Java using Java8+ - Stream API.
Sha 76110 silver badges39 bronze badges answered Aug 10 at 6:18
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