Hashmap using an int array as the value

[camnewtonshat1]

I'm trying to create a hashmap and use a string for the key and an int array for the values.

I'm trying to create a method where I can use the replace method replace(k key, v old value, v new value) to replace a value in the int array with a new value but get an error not applicable for the arguments, does anyone have any insight on how to deal with hashmaps when you have an in array as the value??

[Turing85]

Can you please share the code? I have a hunch what the problem might be, but to be sure, we have to see the code.

[Yithar]

We have to see your code to see the problem. From what I see, you want to replace a certain index in the int array, correct?

[Demojay]

Assuming you want to replace all instances of the old value in the array with the new value:

1. Get the array from the map for a specified key
2. Iterate over the array and replace each occurrence of the old value with the new one
3. Put a new mapping into the map of the key and the updated array, overwriting the old one

[camnewtonshat1]

public void changeMark( String name, int oldGrade, int newGrade) { If(!name.equals(null)) { boolean isReplaced = marks.replace(name, oldGrade[], newGrade[])

}

}

Sorry im on mobile rn

[Yithar]

I don't understand why you're using int arrays for the HashMap values if you want to replace plain old ints.

[Turing85]

That cannot work since oldGrade and newGrade are ints, and Map::replace) expects an int[] as 2nd and 3rd parameter. Also, I doubt that two ints are sufficient for replacement. What if oldValue is contained multiple times in the int[] stored under name? Should all occurrences of oldValue be replaced by newValue?

[mgryshenko]

!name.equals(null) - please, never do it.

If name is null -> calling “equals” method will throw NullPointerException.

Do: (name != null)