ReduceUpdate
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const companies=[
{ name: "company one", category: "f", start:1981, end: 2004},
{ name: "company two", category: "retail", start:1991, end: 2024},
{ name: "company three", category: "f", start:2000, end: 2024},
{ name: "company four", category: "retail", start:1881, end: 2004},
{ name: "company five", category: "sales", start:2001, end: 2025},
{ name: "company six", category: "sales", start:1981, end: 2014},
{ name: "company seven", category: "f", start:1981, end: 2004},
{ name: "company eight", category: "reails", start:2020, end: 2025},
{ name: "company nine", category: "sales", start:1981, end: 2024},
{ name: "company ten", category: "f", start:1991, end: 2014},
];
const ages=[33,12,36,23,77,65,48,33,26,6,15,44];
// for loop <-
for(let i =0; i <ages.length; i++){
console.log(ages[i])
}
//for each
companies.forEach((company)=> {
company.start++;
});
console.log(companies);
console.log("------for each + if then else----- ");
//for each
companies.forEach((company)=> {
company.start = company.start >2000?
company.start++ : company.start;
});
console.log("------for each + if then else----- ");
console.log(companies);
companies.forEach((company, index, arr)=> {
console.log(company, index, arr);
});
console.log(companies);
console.log("-----for loop company 7 + company 9 ---- ");
total =0;
companies.forEach((company, index, arr) =>{
if(index < arr.length -2){
total =company.start + arr[index+2].start }
});
console.log(total);
console.log("------total age ----- ");
total =0;
ages.forEach((age)=> total +=age);
console.log(total);
console.log("------filter age ----- ");
let kids = ages.filter(age=> age<= 19);
console.log(kids);
console.log(ages);
console.log("------filter age old way----- ");
kids =[];
for(let i =0; i <ages.length; i++){
if(ages[i] <=18) {
kids.push(ages[i]);}
}
console.log(kids);
console.log("------filter companies----- ");
const result = companies.filter((company) => {
return company.start >= 2000 && company.category == "f"
});
console.log(result);
console.log("------filter companies by year----- ");
const result2 = companies.filter((company) => {
return company.start >= 2014 && company.end >=2014 && company.end<=2026
});
console.log(result2);
console.log("----map ex1----- ");
const companyNames= companies.map((company)=> company.name);
console.log(companyNames);
console.log("----map ex2 ${}----- ");
const testmap = companies.map((company)=>{
return `${company.name} [${company.start}-${company.end}]`
});
console.log(testmap);
console.log("----map 2 times----- ");
const ageMap= ages.map(age=> Math.sqrt(age)).map(age=> age*2);
console.log(ageMap);
console.log("----Array function -sorting---- ");
const sortedCompanies = companies.sort((c1,c2) =>
c2.start > c1.start ? 1 : -1);
console.log(sortedCompanies);
console.log("----Array function -sorting 2---- ");
const sortedCompanies1 = companies.sort((c3,c2) =>
c3.start > c2.start ? 1 : -1);
console.log(sortedCompanies1);
// reducer
console.log("-------reducer---------");
a = [5,8,6, 10,9];
const maxNum = a.reduce((max, current) => (current > max ? current : max), a[0]);
console.log(maxNum);
console.log("-------reducer. max---------");
const arr = [5, 7, 9, 11, 51, 43, 55, 6, 87, 12];
const maxValue = (a, b) => (a > b ? a : b);
function seqeMax(arr) {
let result = arr[0];
for (let element of arr) {
result = maxValue(result, element);
}
return result;
}
console.log(seqeMax(arr)); // Output: 87
console.log("-------reducer. min---------");
const minValue = (a, b) => (a < b ? a : b);
function seqeMin(arr) {
let result = arr[0];
for (let element of arr) {
result = minValue(result, element);
}
return result;
}
console.log(seqeMin(arr)); // Output: 5
console.log("-------design pattern ==> reduce function---------");
const sum = (a, b) => (a+b);
function seqe3(fn, arr, init) {
let result = init;
for (let element of arr) {
result = fn(result, element);
}
return result;
}
console.log(seqe3(sum, arr, 0));
console.log(seqe3(maxValue, arr, -99999));
console.log(seqe3(minValue, arr, 999999));
console.log("-------design pattern ==> reduce function---------");
let agesum =0;
for(let i =0; i <ages.length;i++){
agesum = agesum +ages[i];
}
console.log(agesum);
//ex 1
console.log("-------reducing function way. totla =0---------");
const ageSum = ages.reduce((total,age)=>{
return total + age;
}, 0);
console.log(ageSum);
//ex 2
console.log("-------reducing function way. totla =0---------");
console.log("const totalYears = compainies.reduce(()=>{},0);");
const totalYears = companies.reduce((total, company)=>{
return company.end >=2025 ? total + (company.end - company.start) : total;
}, 0);
console.log(totalYears);
console.log("------add index--------");
const totalYears1 = companies.reduce((total, company, index) => {
console.log(`Processing index: ${index}, Company: ${company.name}`);
return company.end >= 2025 ? total + (company.end - company.start) : total;
}, 0);
console.log("Total Years:", totalYears1);
JavaScript
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