I'm wondering for the simplest method for how to run a specific function for each object in an array (or other list type)
My goal is to be able create a list of objects, and have each object run a specific function as it passes through the iterator.
I've tried a for loop on an arraylist
for (int i = 0; i < testList.size(); i++)
{
this = textList.get(i);
this.exampleFunction();
}
But this gives me a 'Variable expected' error
Assuming you're using Java 8+, and you have a Collection<TypeInList> you could call Collection.stream() and do a forEach on that. Like,
testList.stream().forEach(TypeInList::function);
Your current approach is trying to do things with this that cannot be done. It could be fixed like,
for (int i = 0; i < testList.size(); i++)
{
TypeInList that = testList.get(i); // this is a reserved word.
that.function();
}
or
for (TypeInList x : testList) {
x.function();
}
stream(). Iterable (and therefore every Collection) has its own forEach method.
There are multiple ways to iterate through a list, but the easiest I personally find is like this:
Assuming that your list contains String objects e.g.:
List<String> list = new ArrayList();
list.add("Hello");
list.add("World");
for(String current : list){
System.out.println(current);
}
The loop will iterate twice, and console will output the following:
Hello
World
This approach doesn't rely on indexes (as how you're using it in your question), as such I find it easy to use for iterating through a single list.
However the disadvantage is that if you have 2 separate lists that you would like to iterate through, the lack of indexes makes it a bit more complicated. The easier approach for iterating through multiple lists would be using the traditional approach, something like this:
for(int i=0; i<list.size(); i++){
int x = list1.get(i);
int y = list2.get(i);
}
As such your use-case really determines the ideal method you can adopt.
forloop) docs.oracle.com/javase/tutorial/java/nutsandbolts/for.htmlFoo foo = textList.get(i); foo.function();this.function?