He estado luchando con una tarea que he estado haciendo con fines de aprendizaje. Tengo un objeto con algunos estudiantes adentro y quiero calcular las calificaciones promedio de Steven.
Ejemplo:
const students = [ { name: 'John', surname: 'Johnson', faculty: 'Faculty of Science', modules: [ { title: 'Operating systems', marks: [10, 10, 9] }, { title: 'Algorythms', marks: [8, 10, 8] }, { title: 'Statistics', marks: [9, 7, 8] }, ] }, { name: 'Steven', surname: 'Stevenson', faculty: 'Faculty of Science', modules: [ { title: 'Operating systems', marks: [7, 6, 9] }, { title: 'Algorythms', marks: [7, 8, 9] }, { title: 'Statistics', marks: [6, 8, 10] }, ] }, ];Usando el método de filtro, pude filtrar solo a Steven del objeto dado.
const studentSteven = students.filter(student => student.name === 'Steven');¿Cómo puedo calcular su nota media de todos los módulos? Me gustaría lograr esto usando métodos de matriz. Cualquier consejo sería muy apreciado.
Cree una matriz de marcas con flatMap .
reduce sobre esa matriz para crear un promedio general.
Devuelve un objeto actualizado.
const students=[{name:"John",surname:"Johnson",faculty:"Faculty of Science",modules:[{title:"Operating systems",marks:[10,10,9]},{title:"Algorythms",marks:[8,10,8]},{title:"Statistics",marks:[9,7,8]}]},{name:"Steven",surname:"Stevenson",faculty:"Faculty of Science",modules:[{title:"Operating systems",marks:[7,6,9]},{title:"Algorythms",marks:[7,8,9]},{title:"Statistics",marks:[6,8,10]}]}]; const out = students.map(obj => { // Destructure the modules property from the // rest of the object properties const { modules, ...rest } = obj; // Return each marks array, and then flatten them const marks = modules.flatMap(obj => obj.marks); // `reduce` over the marks array to create a overall // sum, divide it by the number of marks, // and round up the returned floating-point number const average = Math.round(marks.reduce((acc, c) => { return acc + c; }, 0) / marks.length); // Return a new updated object return { ...rest, average, modules }; }); console.log(out);Documentación adicional
const students = [ { name: 'John', surname: 'Johnson', faculty: 'Faculty of Science', modules: [ { title: 'Operating systems', marks: [10, 10, 9] }, { title: 'Algorythms', marks: [8, 10, 8] }, { title: 'Statistics', marks: [9, 7, 8] }, ] }, { name: 'Steven', surname: 'Stevenson', faculty: 'Faculty of Science', modules: [ { title: 'Operating systems', marks: [7, 6, 9] }, { title: 'Algorythms', marks: [7, 8, 9] }, { title: 'Statistics', marks: [6, 8, 10] }, ] }, ]; var studentSteven = students.filter(student => student.name === 'Steven'); studentSteven = studentSteven[0] let g = 0; let sum = 0; for(i = 0;i < studentSteven.modules.length;i++){ sum += studentSteven.modules[i].marks.reduce((s,t)=>{ g++ return s + t }) g++ } avg = sum/gPuede map sobre la matriz de estudiantes y para cada estudiante nuevamente map sobre la matriz de módulos y agregar una propiedad llamada promedio de averageMarks a cada objeto de módulo.
const students = [ { name: "John", surname: "Johnson", faculty: "Faculty of Science", modules: [ { title: "Operating systems", marks: [10, 10, 9] }, { title: "Algorythms", marks: [8, 10, 8] }, { title: "Statistics", marks: [9, 7, 8] }, ], }, { name: "Steven", surname: "Stevenson", faculty: "Faculty of Science", modules: [ { title: "Operating systems", marks: [7, 6, 9] }, { title: "Algorythms", marks: [7, 8, 9] }, { title: "Statistics", marks: [6, 8, 10] }, ], }, ]; const updatedStudents = students.map((st) => ({ ...st, modules: st.modules.map((mod) => ({ ...mod, averageMarks: mod.marks.reduce((sum, m) => sum + m) / mod.marks.length, })), })); console.log(updatedStudents); Si también necesita calcular el promedio de todos los módulos, puede encadenar el resultado anterior con otro map y agregar una propiedad average para cada estudiante.
const students = [ { name: "John", surname: "Johnson", faculty: "Faculty of Science", modules: [ { title: "Operating systems", marks: [10, 10, 9] }, { title: "Algorythms", marks: [8, 10, 8] }, { title: "Statistics", marks: [9, 7, 8] }, ], }, { name: "Steven", surname: "Stevenson", faculty: "Faculty of Science", modules: [ { title: "Operating systems", marks: [7, 6, 9] }, { title: "Algorythms", marks: [7, 8, 9] }, { title: "Statistics", marks: [6, 8, 10] }, ], }, ]; const updatedStudents = students .map((st) => ({ ...st, modules: st.modules.map((mod) => ({ ...mod, averageMarks: mod.marks.reduce((sum, m) => sum + m) / mod.marks.length, })), })) .map((st) => ({ ...st, average: st.modules.reduce((sum, { averageMarks }) => sum + averageMarks, 0) / st.modules.length, })); console.log(updatedStudents);