Print ArrayList

java arrays printing arraylist

799,638

Solution 1

list.toString() is good enough.

The interface List does not define a contract for toString(), but the AbstractCollection base class provides a useful implementation that ArrayList inherits.

Solution 2

Add toString() method to your address class then do

System.out.println(Arrays.toString(houseAddress));

Solution 3

From what I understand you are trying to print an ArrayList of arrays and one way to display that would be

System.out.println(Arrays.deepToString(list.toArray()));

Solution 4

since you haven't provide a custom implementation for toString() method it calls the default on which is going to print the address in memory for that object

solution in your Address class override the toString() method like this

public class Address {

int addressNo ; 
....
....
...

protected String toString(){
    return Integer.toString(addressNo);
}

now when you call

houseAddress.get(i)  in the `System.out.print()` method like this

System.out.print( houseAddress.get(i) ) the toString() of the Address object will be called

Solution 5

You can simply give it as:

System.out.println("Address:" +houseAddress);

Your output will look like [address1, address2, address3]

This is because the class ArrayList or its superclass would have a toString() function overridden.

Hope this helps.

View more solutions

799,638

Author by

dancooper93

Updated on February 18, 2022

Comments

dancooper93 over 2 years
I have an ArrayList that contains Address objects.

How do I print the values of this ArrayList, meaning I am printing out the contents of the Array, in this case numbers.

I can only get it to print out the actual memory address of the array with this code:
```
for(int i = 0; i < houseAddress.size(); i++) {   
    System.out.print(houseAddress.get(i));
}  
```
- Paul Nikonowicz over 12 years
  
  do you want the address location in memory?
- dancooper93 over 12 years
  
  sorry, i don't understand what you mean. the arraylist is storing the address pointing to the array, and i want to print the contents of the array, but I don't know how to go about it.
- antony.trupe over 12 years
  
  I tried to reword the question to make it clearer.
- Kuldeep Jain over 12 years
  
  By Address, he mean House address. I think.
- A.H. over 12 years
  
  @dancooper93: Just add the complete declaration of houseAddress including the generics parameter to your question.
- dancooper93 over 12 years
  
  houseAddress is just the name of my ArrayList, it contains an address pointing to an Array which contains the actual numbers, I want to be able to print these numbers through the ArrayList.
- Tamás over 12 years
  
  Okay, I'm completely confused now. You say you have an ArrayList, which contains an address pointing to an Array. How did you obtain the address of the Array that you put in the ArrayList? In Java, you should not be able to get your hands on any raw pointers (at least not easily).
- antony.trupe over 12 years
  
  you can't point to memory locations in Java.
- antony.trupe over 12 years
  
  try including a larger code sample, that may help us infer the question.
- Louis Wasserman over 12 years
  
  Please, just give us the declaration of the houseAddress variable, and some sample code for the elements that it contains.
- dancooper93 over 12 years
  
  ok, in my contructor the line to declare my ArrayList is houseAddress = new ArrayList<Numbers>(); with Numbers being the name of the Array in my other class
beckah over 9 years

This would only work for an array, not an array list. You can not provide houseAddress as an argument for Arrays.toString() because it is not of type Array.
21stking over 9 years

@Mr.Goose i do not get your question quite clear, what do you mean?
Tom about 9 years

This is not different from OPs current code. The problem remains.
geniushkg over 8 years

in my opinion looping is only possible wayout here , if anyone knows better option please share.
Asha almost 8 years

The same output is print by System.out.println(list);
Ishan Srivastava almost 7 years

p.s. it is least controvercial because you are not doing any unnecesary conversions over here like converting ArrayList to Array and then converting it to string to print it
Beginner over 6 years

list is houseAddress here: Arrays.toString(houseAddress.toArray())
compor over 5 years

Welcome to Stack Overflow. Please review the How to Answer section and edit your question accordingly.
Hanif about 5 years

AbstractCollection already overrides toString() to print the contents of its elements. So, just list.toString() prints the toString() of all its elements. This is true for all collections.
Gabriel Pellegrino almost 5 years

call to .toString() is redundant.
Brooklyn99 about 3 years

I donot think toString is required in this case. ArrayList overrides AbstractCollection class and hence it will take care of printing the values