I have a simple idea on my mind but I am not sure how to implement it properly... Here's the deal:
Say there is an ArrayList called myList of size 5 and then there is an Integer called testNumber. The values inside myList and/or testNumber are irrelevant.
What I need to do is compare the testNumber variable with each of myList's integers
and if testNumber doesn't equal to none of them, then perform an operation (i.e. System.out.println("hi");).
How should I go about it..?
ArrayList has a method called contains() which is suitable for this task:
Returns true if this list contains the specified element. More formally, returns true if and only if this list contains at least one element e such that (o==null ? e==null : o.equals(e)).
You can use it as follow:
if(!myList.contains(testNumber)) {
PerformOperation();
}
... == false, write ! .... For booleans == and != are only sensible if both sides are not constant.
You simply do
if (!myList.contains(testNumber))
System.out.println("no element equals " + testNumber);
Strictly speaking this probably doesn't "compare each element to testNumber". So, if you're actually interested in the "manual" way of comparing each element, here's how:
boolean found = false;
for (int i : myList) {
if (i == testNumber)
found = true;
}
if (!found)
System.out.println("no element equals " + testNumber);
contains method compares each element, until a fitting one is found. (It used the equals method instead of ==, too.)