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There are numbers in an array like 54321
array = ["54321"] ;
Now how can I print in console
54321
5432
543
54
5
I don't want to print it manually, I want to print it dynamically..
Thanks in advance.
const array = ["54321"];
const print = ([x]) => {
if (x.length === 0) return;
console.log(x);
print([x.slice(0, -1)]);
}
print(array)
You can split the string into array and the use reduce function
ler arr = array[0].split('');
let result = arr.reduce((acc,i) => {
acc.newarr.push(arr.slice(0,acc.counter).join(''));
acc.counter--;
return acc;
},
{newarr:[],counter:5});
console.log(result);
const array = ["54321"];
const un_print = ([str]) =>
Array.from(
{ length: str.length },
(_, i) => (i + 1) + '. ' + str.slice(0, str.length - i)
)
.forEach((v) => console.log(v));
un_print(array);
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I am trying to make a recursive function for this parameters. Function should determine the nth element of the row
a_0 = 1
a_k = k*a_(k-1) + 1/k
k = 1,2,3...
I am trying really hard to do this but i cant get a result. Please help me to do this
I came up with this but it is not a recursive function. I can not do this as a recursive function
let a = 1
let k = 1
let n = 3
for (let i = 1; i<=n; i++){
a = i*a + 1/i
}
console.log(a)
Here's the recursive function you're looking for, it has two conditions:
k == 0 => 1
k != 0 => k * fn(k - 1) + 1/k
function fn(k) {
if(k <= 0) return 1;
return k * fn(k - 1) + 1/k;
}
console.log(fn(1));
console.log(fn(2));
console.log(fn(3));
console.log(fn(4));
Note: I changed the condition of k == 0 to k <= 0 in the actual function so it won't stuck in an infinite loop if you pass a negative k
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I make a site where the color of the div is randomly generating compared to this array:
let pastelColor = [
'ffaacc','ffbbcc','ffcccc','ffddcc','ffeecc','ffffcc','ffaadd','ffbbdd','ffccdd','ffdddd','ffeedd','ffffdd',
'ffaaee','ffbbee','ffccee','ffddee','ffeeee','ffffee','ffaaff','ffbbff','ffccff','ffddff','ffeeff','ffffff',
'ccaaff','ccbbff','ccccff','ccddff','cceeff','ccffff','ccaaee','ccbbee','ccccee','ccddee','cceeee','ccffee',
'ccaadd','ccbbdd','ccccdd','ccdddd','cceedd','ccffdd','ccaacc','ccbbcc','cccccc','ccddcc','cceecc','ccffcc'
]
I tried several Algo with Case Switch but the function took too much room, I was wondering in curiosity if an algo would be able to generate this array ?
Thank you in advance for those who answer
if an algo would be able to generate this array ?
Sure. If you need that array in that exact order:
let pastelColor = Array.from("abcdef".repeat(8), (ch, i) =>
(([a,...r]) => a+a+ch+ch+r[~~(i/6)%4].repeat(2))(i<24 ? "fcdef" : "cfedc")
);
console.log(pastelColor);
If you are not really interested in the array with color codes, but only in the generation of a random color from it, then:
let pick = str => str[Math.floor(Math.random() * str.length)].repeat(2);
let pastelColor = pick("cf") + pick("abcdef") + pick("cdef");
console.log(pastelColor);
You need to fill the array with the converted hexadecimal color with randomly generated integers ranging from 0 to 255 like this:
const getRandomInt = (min, max) => {
min = Math.ceil(min);
max = Math.floor(max);
return Math.floor(Math.random() * (max - min) + min);
}
const getRandomColorUnit = () => {
const color = getRandomInt(0, 256).toString(16);
if (color.length < 2) return '0' + color;
return color;
};
const getRandomColor = () => `#${getRandomColorUnit()}${getRandomColorUnit()}${getRandomColorUnit()}`;
const colors = new Array(100).fill(0).map(getRandomColor);
console.log(colors);
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Can anyone explain in detail how this piece of code works?
const yourAmazingFunction = (salaries) => Object.values(salaries).reduce((acc, el) => acc + el, 0);
specifically this:
((acc, el) => acc + el, 0);
Here's all the code:
const nonEmptySalaries = {
John: 100,
Ann: 160,
Pete: 130
};
const emptySalaries = {};
const yourAmazingFunction = (salaries) => Object.values(salaries).reduce((acc, el) => acc + el, 0);
const firstResult = yourAmazingFunction(nonEmptySalaries)
const secondResult = yourAmazingFunction(emptySalaries)
console.log(firstResult); // 390
console.log(secondResult); // 0 ```
Take all of the values (in this case an array [100, 160, 130])
Loop over the array values, setting acc to the result of the last call of the callback, or 0 if this is the first call, and el to the current element. Basically add together each number (callback(0, 100) then callback(100, 160) then callback(260, 130) to return 390).
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how can this type of loop be overwritten
let num - fieldOffset[0];
for (let i = 1; i < fieldOffset.length; i++) {
if (fieldOffset[i] < fieldOffset[i - 1]) {
num += fieldOffset[i];
}
}
as an anonymous function of the following type:
const reducer = (accumulator, currentValue) => accumulator + currentValue;
array1.reduce(reducer)
Using the third (optional) argument of Array.prototype.reduce should do the trick:
num = fieldOffset.reduce((acc, value, index) => acc += (index && (value > fieldOffset[index - 1])) ? value : 0, 0);
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How can I find an extra character between two strings in an optimal way.
Ex1: S1 - 'abcd', S2 - 'abcxd', output - 'x'
Ex2: S1 - '100001', S2 - '1000011', output - '1'
We can do this by traversing linearly and comparing each character in O(n). I want this to be done in much more optimal way, say in O(logn)
Baseline method (O(n)): Just comparing chars and narrowing in on both sides each cycle.
function findDiffChar(base, baseExtraChar) {
let extraLastIndex = base.length;
let lastIndex = extraLastIndex - 1;
for (let i = 0; i < extraLastIndex / 2; i++) {
console.log(`Loop: ${i}`);
if (base[i] !== baseExtraChar[i])
return baseExtraChar[i];
if (base[lastIndex - i] !== baseExtraChar[extraLastIndex - i])
return baseExtraChar[extraLastIndex - i];
}
return false;
}
console.log(findDiffChar('FOOOOOAR', 'FOOOOOBAR')); // B
Improved method using binary search (O(log n)): Compare halves until you've narrowed it down to one character.
function findDiffChar(base, baseExtraChar) {
if (baseExtraChar.length === 1) return baseExtraChar.charAt(0);
let halfBaseLen = Number.parseInt(base.length / 2) || 1;
let halfBase = base.substring(0,halfBaseLen);
let halfBaseExtra = baseExtraChar.substring(0,halfBaseLen);
return (halfBase !== halfBaseExtra)
? findDiffChar(halfBase, halfBaseExtra)
: findDiffChar(base.substring(halfBaseLen),baseExtraChar.substring(halfBaseLen));
}
console.log(findDiffChar('FOOOOAR', 'FOOOOBAR')); // B
console.log(findDiffChar('---------', '--------X')); // X
console.log(findDiffChar('-----------', '-----X-----')); // X
console.log(findDiffChar('------------', '---X--------')); // X
console.log(findDiffChar('----------', '-X--------')); // X
console.log(findDiffChar('----------', 'X---------')); // X