I am new and learning programming. I wondered if there is a way to get a specific value + key or (in this case) key from an object if it passes a condition.
function miti (a){
let obj = {};
let num;
for(let i =0; i < a.length; i++){
num = a[i]
if(obj[num] === undefined){
obj[num]= 1
} else {
obj[num] ++
}
}
//Now I have created an object that records the frequancy of each presented number.
if(Object.values(obj) === 1){
return
}
}
console.log(miti([1,2,1,3,4,3,4,5))
From the above code, I would like to extract a lonely number with no pairs, I built an object that records each frequency from a given array.
Please be a little descriptive since I am a newbie.
Object.values(obj) === 1 doesn't make any sense because Object.values returns an array, which definitely won't be equal to a number.
Iterate through the entries of the object (the key-value pairs) and return the first entry for which the value is 1.
function miti(a) {
let obj = {};
let num;
for (let i = 0; i < a.length; i++) {
num = a[i]
if (obj[num] === undefined) {
obj[num] = 1
} else {
obj[num]++
}
}
for (const entry of Object.entries(obj)) {
if (entry[1] === 1) {
return entry[0];
// or return entry, if you want the whole entry and not just the key
}
}
}
console.log(miti([1, 2, 1, 3, 4, 3, 4, 5]))Or .find the entry matching the condition and return it.
function miti(a) {
let obj = {};
let num;
for (let i = 0; i < a.length; i++) {
num = a[i]
if (obj[num] === undefined) {
obj[num] = 1
} else {
obj[num]++
}
}
return Object.entries(obj)
.find(entry => entry[1] === 1)
[0];
}
console.log(miti([1, 2, 1, 3, 4, 3, 4, 5]))Or, using the Array methods .forEach() and .find() in combination with Object.keys() you can do it like that:
function firstUniqueValue(a) {
let obj = {};
a.forEach(k=>obj[k]=(obj[k]||0)+1);
return Object.keys(obj).find(k=>obj[k]==1);
}
console.log(firstUniqueValue([1, 2, 1, 3, 4, 3, 4, 5]))