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# Two ArrayList equalty index.

Posted on 2006-07-11
Medium Priority
329 Views
I have these two arrayLists

ArrayList myArrayList = new ArrayList();
ArrayList yourArrayList = new ArrayList();

I want a method isEqualTo() to test if first element in myArrayList is equal to the last element in yourArrayList, if it is equal return true and false otherwise .

I tried this code but it was not work:

if(!myArrayList.isEmpty())
{
for(int k = yourArrayList.size() ; k < yourArrayList.size() ; k--)
{
if(yourArrayList.get(k).equals(myArrayList.get(1)))
return true;      /*System.out.println("\nFound\n");  */
}
return false;
}
0
Question by:javamate06

LVL 9

Expert Comment

ID: 17079910
I don't know why you're using a for loop .. ??
as you mentioned you want to compare the first element in *myArrayList* with the last element in *yourArrayList* ..
so do it simply :
{
ArrayList myArrayList = new ArrayList();
ArrayList yourArrayList = new ArrayList();

// Insert element to ArrayLists

if(myArrayList.Count != 0 && yourArrayList.Count != 0)
{
int LastElement = yourArrayList.Count-1;

if(yourArrayList[LastElement].Equals(myArrayList[0]))
return true;
}
return false;
}

0

LVL 15

Accepted Solution

bpmurray earned 200 total points
ID: 17079915
Your code checks to find the last element in yourArrayList that matches the second element in myArrayList. To see if the last element in yourArrayList is the same as the first in myArrayList, you can put it all in one line if you like, like this:

return ((!myArrayList.isEmpty()) && yourArrayList.get(yourArrayList.size()-1).equals(myArrayList.get(0)));

If you want to retail legibility, you can do it like this:

if (!myArrayList.isEmpty())
{
if (yourArrayList.get(yourArrayList.size()-1).equals(myArrayList.get(0)))
return true;     /*System.out.println("\nFound\n");  */
}
return false;  /* If the array is empty, it should be false too! */

I'm assuming that this is Java or some other language that bases indices from zero. If the index is one-based, the comparison should be:

if (yourArrayList.get(yourArrayList.size()).equals(myArrayList.get(1)))
0

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