typescript method searching for and merging all keys starting with the specified prefix

Question

typescript method searching for and merging all keys starting with the specified prefix

Take a look at this object:

https://i.sstatic.net/V0xvI.png

Where each property in system(1) holds tridimensional coordinates. Is there a more efficient method to consolidate properties with the same prefix without nesting loops within loops? My goal is to accomplish the following:

// Coordinates of points in systems prefixed with lwb
setOfValidPoint1 = [[3.370316528, 0.050628689000000004, 0.20987313800000001], 
                    [3.4050299070000003, 0.559079376, 0.267691772], 
                    [2.990670776, 0.05074561700000001, 0.21216622899999998]]

// Coordinates of points in systems prefixed with lwb
setOfValidPoint2 = [[3.440000732, 0.04970323, 0.210814064], 
                    [3.4748417970000003, 0.5596490780000001, 0.268024719]]

// Coordinates of points in systems prefixed with mrf (one point)
setOfValidPoint3 = [[3.51507, 0.777428, 0.36277]]

And so on...

arrays typescript object

Answer 1

Answer №1

When you utilize the reduce() method, you're essentially avoiding direct loops (even though there's an internal iteration loop over the input data):

function mergeData(data: { [key: string]: number[] }) {

    return Object.getOwnPropertyNames(data).reduce((accumulator, key) => {

        const prefix = key.split('_')[0];

        if (accumulator[prefix] === undefined) {
            accumulator[prefix] = [];
        }

        accumulator[prefix].push(data[key]);

        return accumulator;

    }, {} as {[key: string]: number[][] })
}

Here's a practical example:

const inputData = {
    a_xx: [1, 2, 3],
    b_xx: [9, 8, 7],
    a_yy: [11, 22, 33],
    b_yy: [9, 8, 7],
    c: [9, 8, 7],
};

function mergeData(inputData) {

    return Object.getOwnPropertyNames(inputData).reduce((accumulator, key) => {
    
        const prefix = key.split('_')[0];
        
        if (accumulator[prefix] === undefined) {
            accumulator[prefix] = [];
        }
        
        accumulator[prefix].push(inputData[key]);
        
        return accumulator;
        
    }, {});
}

console.log(mergeData(inputData));

Answer 2

When you utilize the reduce() method, you're essentially avoiding direct loops (even though there's an internal iteration loop over the input data):

function mergeData(data: { [key: string]: number[] }) {

    return Object.getOwnPropertyNames(data).reduce((accumulator, key) => {

        const prefix = key.split('_')[0];

        if (accumulator[prefix] === undefined) {
            accumulator[prefix] = [];
        }

        accumulator[prefix].push(data[key]);

        return accumulator;

    }, {} as {[key: string]: number[][] })
}

Here's a practical example:

const inputData = {
    a_xx: [1, 2, 3],
    b_xx: [9, 8, 7],
    a_yy: [11, 22, 33],
    b_yy: [9, 8, 7],
    c: [9, 8, 7],
};

function mergeData(inputData) {

    return Object.getOwnPropertyNames(inputData).reduce((accumulator, key) => {
    
        const prefix = key.split('_')[0];
        
        if (accumulator[prefix] === undefined) {
            accumulator[prefix] = [];
        }
        
        accumulator[prefix].push(inputData[key]);
        
        return accumulator;
        
    }, {});
}

console.log(mergeData(inputData));

Answer 3

Answer №2

It's difficult to say if this meets your exact requirements without more information, but here is a sample solution utilizing just one loop.

class SampleClass{
    item1: number[] = [2.9102, 0.0346, 0.1834];
    item2: number[] = [2.9456, 0.5598, 0.2493];
    object1: number[] = [3.1074, 0.6789, 0.2536];
    object2: number[] = [3.0623, 0.0452, 0.1979];
}

let sample = new SampleClass();

let itemList: number[][] = []
let objectList: number[][] = []

for(var key in sample){
    if(sample.hasOwnProperty(key)){
        let name_segments: String[] = key.split('');
        switch(name_segments[0]){
            case "item":
                itemList.push(sample[key]);
                break;
            case "object":
                objectList.push(sample[key]);
                break;
            default:
                console.log("Unexpected property found")
                break;
        }
    }
}

console.log("Items List");
console.log(itemList);
console.log("Objects List");
console.log(objectList);

The output generated by the above script is:

Items List
[ [ 2.9102, 0.0346, 0.1834 ], [ 2.9456, 0.5598, 0.2493 ] ]
Objects List
[ [ 3.1074, 0.6789, 0.2536 ], [ 3.0623, 0.0452, 0.1979 ] ]

Answer 4

It's difficult to say if this meets your exact requirements without more information, but here is a sample solution utilizing just one loop.

class SampleClass{
    item1: number[] = [2.9102, 0.0346, 0.1834];
    item2: number[] = [2.9456, 0.5598, 0.2493];
    object1: number[] = [3.1074, 0.6789, 0.2536];
    object2: number[] = [3.0623, 0.0452, 0.1979];
}

let sample = new SampleClass();

let itemList: number[][] = []
let objectList: number[][] = []

for(var key in sample){
    if(sample.hasOwnProperty(key)){
        let name_segments: String[] = key.split('');
        switch(name_segments[0]){
            case "item":
                itemList.push(sample[key]);
                break;
            case "object":
                objectList.push(sample[key]);
                break;
            default:
                console.log("Unexpected property found")
                break;
        }
    }
}

console.log("Items List");
console.log(itemList);
console.log("Objects List");
console.log(objectList);

The output generated by the above script is:

Items List
[ [ 2.9102, 0.0346, 0.1834 ], [ 2.9456, 0.5598, 0.2493 ] ]
Objects List
[ [ 3.1074, 0.6789, 0.2536 ], [ 3.0623, 0.0452, 0.1979 ] ]

typescript method searching for and merging all keys starting with the specified prefix

Answer №1

Answer №2

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