Sorting an array into subarrays

Question

I have an array of strings that have 3 subsections that I am looking to sort. See the below example

String[] teams = new String[5];
teams[0] = "Header1";
teams[1] = "Candy";
teams[2] = "Apples";
teams[3] = "Fruit";
teams[4] = "Header2";
teams[5] = "Candy";
teams[6] = "ZZZ";
teams[7] = "Fruit"; 
teams[8] = "E";
teams[9] = "Header3";
teams[10] = "C";
teams[11] = "T";
teams[12] = "A";

I want to sort each of the subsections while leaving the Headers1-3 in place. Should I break up my array into 3 sub arrays based off of the known entries (Headers1-3) and just use array.sort or is there an easier way that I am unaware of? Note my string array is a fixed length of entries and each Header is in a known position (i.e Header 2 is always in position 4).

You should learn about objects and classes. Java is an OO language. You should have a List<Section>, containing 3 objects. Each object would have a title (String), and probably a List<String> elements. You could now easily sort each List<Element> inside each Section object. Don't mix unrelated things in the same array or collection. Don't use arrays in general, and prefer collections. — JB Nizet
– JB Nizet, Commented Aug 10, 2018 at 21:21
Also, you can't possbly store 13 elements in an array of length 5. — JB Nizet
– JB Nizet, Commented Aug 10, 2018 at 21:22

Magdrop · Accepted Answer · 2018-08-10 21:48:45Z

4

I think you are almost there. Using Arrays.sort and specifying the indices seems the easiest.

public static void sort(int[] arr, int from_Index, int to_Index)

The range is defined as follows

The range to be sorted extends from index fromIndex, inclusive, to index toIndex, exclusive.

In this example, using the following code:

Arrays.sort(teams,1,4);
Arrays.sort(teams,5,9);
Arrays.sort(teams,10,13);

for (String s : teams) {
    System.out.println(s);
}

produces the following output:

Header1
Apples
Candy
Fruit
Header2
Candy
E
Fruit
ZZZ
Header3
A
C
T

I would suggest not to keep your dataset that way because there are better ways to organize the data than to fit them into a single array.

edited Aug 10, 2018 at 21:48

answered Aug 10, 2018 at 21:36

Magdrop

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