Looping through JSON data in Java Script is a common task for

Question

Looping through JSON data in Java Script is a common task for

How can I extract and store all grades from the provided JSON data for every year into an array? I am new to JavaScript, so any explanation would be helpful. The expected array based on this example should be [2,4,2,5,4,5,4.5,2,3.5,5,5,5,5,5]

{
    "first_name": "Ala",
    "last_name": "Kowalski",
    "birth_date": "29 AUG 1990",
    "indeks_number": "9454530",
    "year_of_study": "2",
    "courses": {
        "2013": {
            "AlgorithmsI": {
                "grades": {
                    "exercices": [
                        2,
                        4
                    ],
                    "lecture": [
                        2,
                        5
                    ]
                }
            },
            "BasicPhysicsI": {
                "grades": {
                    "exercices": [
                        4
                    ],
                    "lecture": [
                        5
                    ]
                }
            },
            "ProgrammingI": {
                "grades": {
                    "exercices": [
                        4.5
                    ],
                    "lecture": [
                        2,
                        3.5
                    ]
                }
            }
        },
        "2014": {
            "ProgrammingII": {
                "grades": {
                    "exercices": [
                        5
                    ],
                    "lecture": [
                        5
                    ]
                }
            },
            "BasicPhysicsII": {
                "grades": {
                    "exercices": [
                        5
                    ],
                    "lecture": [
                        5
                    ]
                }
            },
            "AlgorithmsII": {
                "grades": {
                    "exercices": [
                        5
                    ],
                    "lecture": [
                        5
                    ]
                }
            }
        }
    }
}

javascript json recursion

Answer 1

Answer №1

One method I may consider using is utilizing JSON.stringify to loop through the object:

gradesList = [];
JSON.stringify(obj, function(key, value) {
    if (key === 'grades') 
        gradesList = gradesList.concat(value.exercises, value.lecture);
    return value;
});

Explanation of the Process

The purpose of JSON.stringify is to convert an object into a JSON string format. During this process, it traverses through all values within the object at every level. Additionally, it allows for a replacer parameter, which is a function that analyzes each key/value pair encountered. In this situation, the replacer function is utilized not for controlling the conversion into a string but rather to inspect each key/value pair to determine if the key corresponds to 'grades'. If so, the respective grades are appended to the gradesList array. It is important to return value so that the iteration by JSON.stringify continues. The actual result produced by JSON.stringify is disregarded and discarded.

Answer 2

One method I may consider using is utilizing JSON.stringify to loop through the object:

gradesList = [];
JSON.stringify(obj, function(key, value) {
    if (key === 'grades') 
        gradesList = gradesList.concat(value.exercises, value.lecture);
    return value;
});

Explanation of the Process

The purpose of JSON.stringify is to convert an object into a JSON string format. During this process, it traverses through all values within the object at every level. Additionally, it allows for a replacer parameter, which is a function that analyzes each key/value pair encountered. In this situation, the replacer function is utilized not for controlling the conversion into a string but rather to inspect each key/value pair to determine if the key corresponds to 'grades'. If so, the respective grades are appended to the gradesList array. It is important to return value so that the iteration by JSON.stringify continues. The actual result produced by JSON.stringify is disregarded and discarded.

Answer 3

Answer №2

Hey, here's a code snippet you can give a shot.

function getGrades(jsonData) {
    var gradesList = [];
    
    for (var year in jsonData.courses) {
        for (var lesson in jsonData.courses[year]) {
            for (var exerciseGrade in jsonData.courses[year][lesson].grades.exercises) {
                gradesList.push(jsonData.courses[year][lesson].grades.exercises[exerciseGrade]);
            }
            
            for (var lectureGrade in jsonData.courses[year][lesson].grades.lecture) {
                gradesList.push(jsonData.courses[year][lesson].grades.lecture[lectureGrade]);
            }
        }
    }
    
    return gradesList;
}

Answer 4

Hey, here's a code snippet you can give a shot.

function getGrades(jsonData) {
    var gradesList = [];
    
    for (var year in jsonData.courses) {
        for (var lesson in jsonData.courses[year]) {
            for (var exerciseGrade in jsonData.courses[year][lesson].grades.exercises) {
                gradesList.push(jsonData.courses[year][lesson].grades.exercises[exerciseGrade]);
            }
            
            for (var lectureGrade in jsonData.courses[year][lesson].grades.lecture) {
                gradesList.push(jsonData.courses[year][lesson].grades.lecture[lectureGrade]);
            }
        }
    }
    
    return gradesList;
}

Answer 5

Answer №3

let newGrades = [];
let dataObject = <your Object>;

analyzeObj(dataObject);

function analyzeObj(data) {
    for (let key in data) {
        if (key=='exercices' || key=='lectures') {
            for (let i=0;i<data[key].length;i++) {
                newGrades.push(data[key][i]);
            }
        } else {
            analyzeObj(data[key]);
        }
     }
}

Answer 6

let newGrades = [];
let dataObject = <your Object>;

analyzeObj(dataObject);

function analyzeObj(data) {
    for (let key in data) {
        if (key=='exercices' || key=='lectures') {
            for (let i=0;i<data[key].length;i++) {
                newGrades.push(data[key][i]);
            }
        } else {
            analyzeObj(data[key]);
        }
     }
}

Answer 7

Answer №4

Repetitive:

function each(list, func) {
    Object.keys(list).forEach(function (key) {
        var item = list[key];
        func(item, key);
    });
}

function inArray(arr, element) {
    return arr.indexOf(element) > -1;
}

function isSimpleObject(obj) {
    return !!obj && typeof obj === 'object' && obj.constructor === Object;
}

function getValues(data) {
    var values = [];
    each(data, function (item, key) {
        if (inArray(['workouts', 'reading'], key)) {
            values = values.concat(item);
        } else if (isSimpleObject(item)) {
            values = values.concat(getValues(item));
        }
    });
    return values;
}

You can try this out in Node.js by using:

var assert = require('assert');
assert.deepEqual(getValues(sampleData),
                 [2, 4, 2, 5, 4, 5, 4.5, 2, 3.5, 5, 5, 5, 5, 5, 5]);

Replace sampleData with your own JSON information.

Answer 8

Repetitive:

function each(list, func) {
    Object.keys(list).forEach(function (key) {
        var item = list[key];
        func(item, key);
    });
}

function inArray(arr, element) {
    return arr.indexOf(element) > -1;
}

function isSimpleObject(obj) {
    return !!obj && typeof obj === 'object' && obj.constructor === Object;
}

function getValues(data) {
    var values = [];
    each(data, function (item, key) {
        if (inArray(['workouts', 'reading'], key)) {
            values = values.concat(item);
        } else if (isSimpleObject(item)) {
            values = values.concat(getValues(item));
        }
    });
    return values;
}

You can try this out in Node.js by using:

var assert = require('assert');
assert.deepEqual(getValues(sampleData),
                 [2, 4, 2, 5, 4, 5, 4.5, 2, 3.5, 5, 5, 5, 5, 5, 5]);

Replace sampleData with your own JSON information.

Looping through JSON data in Java Script is a common task for

Answer №1

Explanation of the Process

Answer №2

Answer №3

Answer №4

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