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I have an ArrayList of ArrayLists of words where Word is a class.

ArrayList<ArrayList<Word>> arrayColumns = new ArrayList();

with every new column I have to create a new ArrayList of Words and then add that to arrayColumns.

This ArrayList I am creating dynamically and want to name it as arrayWordColumn1, arrayWordColumn2 etc with the addition of every new column. As I don't know how many columns will be there I am trying to write a method to create an ArrayList. Something Like :

public ArrayList<OCRWord> createColumn (count){
    ArrayList<OCRWord> arrayWordColumn+count = new ArrayList();
    return ArrayList;
}

How can I create arrayLists in such a manner so that if count is 1,2,3,4... it should create ArrayLists with names arrayWordColumn1, arrayWordColumn2, arrayWordColumn3 etc.?

In Short the name arrayWordColumn1 should be formed by concatenating two things --> arrayWordColumn + count where count will be 1,2,3,4...

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  • 6
    Why do you want to do that ? Commented Mar 17, 2017 at 11:07
  • How does name matter when arrayColumns will have only reference of your dynamically created array list? Commented Mar 17, 2017 at 11:07
  • 1
    well you could use a Map<String,List<Word>>, which i think gets as close as possible to what you would like to have as "variable" name, where the key of the map would represent your "variable" name. Commented Mar 17, 2017 at 11:08
  • 1
    Variables can't have dynamic names, and there isn't a good reason why they should. Commented Mar 17, 2017 at 11:49
  • Code to the interface, not the implementation, and stop using raw types. The declaration should be List<List<Word>> arrayColumns = new ArrayList<>(); Commented Mar 17, 2017 at 12:07

4 Answers 4

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1

Probably like this

Map<String,List<Word>> map = new HashMap();
map.put("arrayWordColumn1", list);
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3 Comments

Moving to map won't be a good choice for me as there are a lot of dependencies on this. And after that the question remains the same that how can I name the variable arrayWordColumn1, arrayWordColumn2... etc by concatenating two variables like String + count
In Java you can't. All variables must be declared at compile time. You may create a "named reference" by a Map or any other dynamic data structure.
new HashMap<>();
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Declare a map string, list

Map<String,List<Word>> myDynamicMap = new HashMap<>();

to add dynamic variables:

myDynamicMap.put("ListWord_1", list1);
myDynamicMap.put("ListWord_2", someList);
myDynamicMap.put("ListWord_3", anotherList);

to get a list from the map:

myDynamicMap.get("ListWord_3");
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2 Comments

i´m just going to note that a Map<Integer,List<Word>> might be the smoother choice here, as you pretty much only care for the last number(s) even though.
Moving to map won't be a good choice for me as there are a lot of dependencies on this. And after that the question remains the same that how can I name the variable ListWord_1, ListWord_2, ListWord_3...
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you can use this stucture :
ArrayList < Map > i think that's better ArrayList of Map that has Integer Key and list of word is better in the access when you add a new list of word you should use new Integer(value) good luck

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You can get the names of the variables at runtime. After getting these variable names, you can create references by using Map or any other structure, you want.

how to get variable names at runtime

The summary of this is given as follows;

Provide a mechanism to easily and reliably retrieve the parameter names of methods and constructors at runtime via core reflection.

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