Is there a way to use the sort() function to further categorize objects that have been moved to the bottom of an array during sorting?

Question

Is there a way to use the sort() function to further categorize objects that have been moved to the bottom of an array during sorting?

My task in JavaScript involves sorting within a single sort() function that is passed as a parameter.

Specifically, I need to sort objects first by category and then further sort them by subcategory using:

return item1.category.localeCompare(item2.category) : item1.subCategory.localeCompare(item2.subCategory)

However, for objects without a category, I want to place them at the bottom of the list. The current approach I'm using does this but the items are not grouped together by subcategory as desired.

Here's an example of how the sorted objects look now:

[
  {'category':'cat1', 'subcategory':'subcat1'},
  {'category':'cat1', 'subcategory':'subcat2'},
  {'category':'cat2', 'subcategory':'subcat1'},
  {'category':'cat2', 'subcategory':'subcat2'}
  {'category':'', 'subcategory':'subcat1'},
  {'category':'', 'subcategory':'subcat2'},
  {'category':'', 'subcategory':'subcat1'},
  {'category':'', 'subcategory':'subcat2'}
]

I would like the final result to be organized by subcategory with empty categories staying grouped together. For instance:

[
  {'category':'cat1', 'subcategory':'subcat1'},
  {'category':'cat1', 'subcategory':'subcat2'},
  {'category':'cat2', 'subcategory':'subcat1'},
  {'category':'cat2', 'subcategory':'subcat2'}
  {'category':'', 'subcategory':'subcat1'},
  {'category':'', 'subcategory':'subcat1'},
  {'category':'', 'subcategory':'subcat2'},
  {'category':'', 'subcategory':'subcat2'}
]

javascript arrays sorting

Answer 1

Answer №1

To begin, prioritize sorting the empty parts to the bottom before comparing the strings within the category and subcategory.

var data = [{ category: 'cat2', subcategory: 'subcat1' }, { category: 'cat1', subcategory: 'subcat1' }, { category: 'cat2', subcategory: 'subcat2' }, { category: '', subcategory: '' }, { category: '', subcategory: 'subcat1' }, { category: '', subcategory: 'subcat2' }, { category: 'cat1', subcategory: 'subcat2' }, { category: 'cat1', subcategory: '' }, { category: 'cat2', subcategory: '' }];

data.sort(function (a, b) {
    return (
        !a.category - !b.category ||                 // place falsy values at the end
        a.category.localeCompare(b.category) ||      // arrange strings alphabetically
        !a.subcategory - !b.subcategory || 
        a.subcategory.localeCompare(b.subcategory) 
    );
});

console.log(data);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 2

To begin, prioritize sorting the empty parts to the bottom before comparing the strings within the category and subcategory.

var data = [{ category: 'cat2', subcategory: 'subcat1' }, { category: 'cat1', subcategory: 'subcat1' }, { category: 'cat2', subcategory: 'subcat2' }, { category: '', subcategory: '' }, { category: '', subcategory: 'subcat1' }, { category: '', subcategory: 'subcat2' }, { category: 'cat1', subcategory: 'subcat2' }, { category: 'cat1', subcategory: '' }, { category: 'cat2', subcategory: '' }];

data.sort(function (a, b) {
    return (
        !a.category - !b.category ||                 // place falsy values at the end
        a.category.localeCompare(b.category) ||      // arrange strings alphabetically
        !a.subcategory - !b.subcategory || 
        a.subcategory.localeCompare(b.subcategory) 
    );
});

console.log(data);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 3

Answer №2

If you want to dynamically sort objects based on multiple properties, you can achieve this by utilizing a helper function and nested sorting logic for as many fields as needed.

function getGeneratedObjects(num){  // helper function to generate sample objects
  return Array(num).fill()
                 .reduce(obj => obj.concat({prop1 : String.fromCharCode(...Array(5).fill().map(_ => ~~(Math.random()*26)+97)),
                                        prop2 : ~~(Math.random()*5)+1,
                                        prop3 : ["London","Paris","Sydney","Berlin","Tokyo","Cairo"][~~(Math.random()*6)],
                                        prop4 : ~~(Math.random()*2+1)+String.fromCharCode(~~(Math.random()*3)+65)
                                       }),[]);
}

function multiLevelSorter(objects,props){
  return objects.sort(function(a,b){
                   var prop = props.find(f => a[f] !== b[f]);
                   return a[prop] < b[prop] ? -1 : 1;
                 });
}

var samples = getGeneratedObjects(50),
sortOrder = ["prop3","prop2","prop4","prop1"],
   sortedData = multiLevelSorter(samples,sortOrder);
sortedData.forEach(item => console.log("{prop1:", item.prop1,"prop2:",item.prop2,"prop3:",item.prop3,"prop4:",item.prop4,"}"));

.as-console-wrapper { max-height: 100% !important; top: 0; }

Therefore, the script above arranges data in the order of priority defined as prop3 -> prop2 -> prop4 -> prop1.

Answer 4

If you want to dynamically sort objects based on multiple properties, you can achieve this by utilizing a helper function and nested sorting logic for as many fields as needed.

function getGeneratedObjects(num){  // helper function to generate sample objects
  return Array(num).fill()
                 .reduce(obj => obj.concat({prop1 : String.fromCharCode(...Array(5).fill().map(_ => ~~(Math.random()*26)+97)),
                                        prop2 : ~~(Math.random()*5)+1,
                                        prop3 : ["London","Paris","Sydney","Berlin","Tokyo","Cairo"][~~(Math.random()*6)],
                                        prop4 : ~~(Math.random()*2+1)+String.fromCharCode(~~(Math.random()*3)+65)
                                       }),[]);
}

function multiLevelSorter(objects,props){
  return objects.sort(function(a,b){
                   var prop = props.find(f => a[f] !== b[f]);
                   return a[prop] < b[prop] ? -1 : 1;
                 });
}

var samples = getGeneratedObjects(50),
sortOrder = ["prop3","prop2","prop4","prop1"],
   sortedData = multiLevelSorter(samples,sortOrder);
sortedData.forEach(item => console.log("{prop1:", item.prop1,"prop2:",item.prop2,"prop3:",item.prop3,"prop4:",item.prop4,"}"));

.as-console-wrapper { max-height: 100% !important; top: 0; }

Therefore, the script above arranges data in the order of priority defined as prop3 -> prop2 -> prop4 -> prop1.

Answer 5

Answer №3

If you prefer, you can utilize the SortedArrayCategory. Here is how the code looks:

//arrTemp = The name of your array.

                                self.sortedArrayCategory = arrTemp.sortedArrayUsingComparator {
                                    (firstObject, secondObject) -> NSComparisonResult in

                                    let item1 = firstObject as! String
                                    let item2 = secondObject as! String
                                    let comparisonResult = item1.compare(item2)
                                    return comparisonResult
                                }

Answer 6

If you prefer, you can utilize the SortedArrayCategory. Here is how the code looks:

//arrTemp = The name of your array.

                                self.sortedArrayCategory = arrTemp.sortedArrayUsingComparator {
                                    (firstObject, secondObject) -> NSComparisonResult in

                                    let item1 = firstObject as! String
                                    let item2 = secondObject as! String
                                    let comparisonResult = item1.compare(item2)
                                    return comparisonResult
                                }

Is there a way to use the sort() function to further categorize objects that have been moved to the bottom of an array during sorting?

Answer №1

Answer №2

Answer №3

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