Java one liner for loop

Question

Here, someone made a one-liner for loop in Python.

Another example is this:

someList = [f(i) for i in range(16)]

which would be a one-liner for this code:

someList = []
for i in range(16):
    someList.append(f(i))

or, in Java:

int[] someList = {}
for (int i = 0; i < 16; i++) {
    someList = append(someList, f(i));
}

such that f is some function that will return an integer.

Now, is there an equivalent one-liner in Java?

Note: Currently, I am using Processing, which is similar to Java, so, any code written in Java might be usable in Processing.

You can't append to an array in Java. Use an ArrayList or simply create array of correct size: int[] someList = new int[16] then do someList[i] = f(i) in the loop. — Andreas, Commented Dec 3, 2016 at 10:51
Is there a reason you need this in one line? I'd argue that you should favor readability over shortness. The for loop solution is easy to understand. Why not just stick with that? — Kevin Workman, Commented Dec 3, 2016 at 16:42

Mureinik · Accepted Answer · 2016-12-03 10:45:31Z

19

Java 8's IntStream to the rescue:

int[] someList = IntStream.range(0, 16).map(i -> f(i)).toArray();

answered Dec 3, 2016 at 10:45

Mureinik

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2

@TimBiegeleisen The original list is the OP is empty, and seems to just be defined as a necessity. The original one-liner OP is trying to emulate creates a new list/array: someList = [f(i) for i in range(16)]
– Mureinik
Commented Dec 3, 2016 at 10:47

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