Simple modulo tester - javascript

I have a simple, modulo based script, which runs for 3 and 6 digits to else. There are also cases for these numbers, which condition should fit also to these numbers.
function caffeineBuzz(n){
var returnvalue;
if (n % 3 == 0)
returnvalue = "Java";
if (n % 3 == 0 && n % 4 == 0)
returnvalue = "Coffee";
if (n % 3 == 0 && n % 2 == 0)
returnvalue = "Java" + "Script"
if (n % 4 == 0 && n % 2 == 0)
returnvalue = "Coffee" + "Script"
else
returnvalue = "mocha_missing!"
return returnvalue;
}
n stands for input, that is an integer and returnvalue should be a string.
Update:
Most specific -> less specific approach helped me, but there are cases, when it returns with wrong value.
function caffeineBuzz(n){
var returnvalue;
if (n % 4 == 0)
returnvalue = "Coffee" + "Script"
else if (n % 3 == 0 && n % 4 == 0)
returnvalue = "Coffee";
else if (n % 3 == 0 && n % 2 == 0)
returnvalue = "Java" + "Script"
else if (n % 3 == 0)
returnvalue = "Java";
else
returnvalue = "mocha_missing!"
return returnvalue;
}

This function is the guesstimation of the answer based on comments.
function caffeineBuzz(n){
//Storing n's modulos to not calculate them multiple times
var mod3 = (n % 3 == 0)
var mod4 = (n % 4 == 0);
var mod2 = mod4 || (n % 2 == 0);
//Maybe: return (mod3 ? ("Java" + (mod4 ? "Coffee" : "")) + (mod2 ? "Script" : "") : "mocha_missing!");
return (mod3 ? ((mod4 ? "Coffee" : "Java") + (mod2 ? "Script" : "")) : ("mocha_missing!"));
}

Related

How could I make this code more effective - js?

function checkValue(val) {
if (val === 1 || val === 4 || val === 7) {
return val - 2
}
if (val === 2 || val === 5 || val === 8) {
return val - 1
}
if (val === 3 || val === 6 || val === 9) {
return val
}
}
console.log(6 - checkValue(6))
how to make this code simple and dynamic to prevent repetitive code writing
function checkValue(val){
const reminder = val % 3;
return reminder ? val - (3 - reminder) : val;
}

Can a Javascript condition be between numbers?

I'm looking to identify a category based on this table:
I have an if statement that seems to work for some conditions, but not others. R, P, and Q are working, but conditions that go between numbers aren't returning the right category.
If statement:
function getCategory(featureFunctionalScore, featureDysfunctionalScore) {
if (featureFunctionalScore == 4 && featureDysfunctionalScore == -2) {
return "Performance";
} else if (featureFunctionalScore == 4 && featureDysfunctionalScore <= -1 && featureDysfunctionalScore > 4) {
return "Attractive"
} else if (featureFunctionalScore <= -1 && featureFunctionalScore > 4 && featureDysfunctionalScore == 4) {
return "Expected"
} else if ((featureFunctionalScore >= -2 && featureFunctionalScore <= 2 && featureDysfunctionalScore == -2) || (featureFunctionalScore == -2 && featureDysfunctionalScore >= -2 && featureDysfunctionalScore <= 2)) {
return "Reverse"
} else if ((featureFunctionalScore == 4 && featureDysfunctionalScore == -2) || (featureFunctionalScore == 2 && featureDysfunctionalScore == -1) || (featureFunctionalScore == -1 && featureDysfunctionalScore == 2) || (featureFunctionalScore == -2 && featureDysfunctionalScore == 4)) {
return "Questionable"
} else {
return "Indifferent"
};
};
Am I missing something important?
Update
This statement works in Excel, but I'm struggling to get it to work in JS:
=IF(OR(AND(C3 <= 2, B3 <= -1), AND(C3 <= -1, B3 <= 2)), "R", IF(AND(C3 <= 2, C3 >= -1, B3 <= 2, B3 >= -1), "I", IF(AND(C3 >= 2,B3 >= -1, B3 <= 2),"A", IF(AND(C3 <= 2, B3 <= 4, B3 >= 2), "M", IF(AND(C3 >= 2, B3 >= 2), "P", "Q")))))
This should be what you're looking for. I'm sure it could be optimized, but it works. JSFiddle: https://jsfiddle.net/yxb7tr9n/
function getCategory(x,y){
var answer = -999;
if (x == 4 && y == 4){
answer = "p";
}else if([-1,0,2].indexOf(x) >= 0 && y == 4){
answer = "A";
}else if((x == -2 && y == 4) || (x == -1 && y == 2) || (x == 4, y == -2)){
answer = "Q";
}else if(x == 4 && [-1,0,2].indexOf(y) >= 0) {
answer = "M";
}else if((x == -1 && [-1,0].indexOf(y) >= 0) || (x == 0 && [-1,0,2].indexOf(y) >= 0) || (x == 2 && [0,2].indexOf(y) >= 0)){
answer = "I";
}else if ((x == -2 && [-2,-1,0,2].indexOf(y) >= 0) || (y == -2 && [-2,-1,0,2].indexOf(x) >= 0)) {
answer = "R";
}else{
answer = "??";
}
return answer;
}
UPDATE: Alternate version using a coordinate mapping system. JSFiddle: https://jsfiddle.net/g2d6p4rL/4/
function indexOfCustom (parentArray, searchElement) {
for ( var i = 0; i < parentArray.length; i++ ) {
if ( parentArray[i][0] == searchElement[0] && parentArray[i][1] == searchElement[1] ) {
return i;
}
}
return -1;
}
function getCategory2(x,y){
var p = [[4,4]];
var q = [[-2,4],[-1,2],[2,-1],[4,-2]];
var a = [[-1,4],[0,4],[2,4]];
var m = [[4,2],[4,0],[4,-1]];
var i = [[0,2],[2,2],[-1,0],[0,0],[2,0],[-1,-1],[0,-1]];
var r = [[-2,2],[-2,0],[-2,-1],[-2,-2],[-1,-2],[0,-2],[2,-2]];
coord = [x,y];
if (indexOfCustom(p,coord) >= 0){
return "p";
} else if (indexOfCustom(q,coord) >= 0){
return "Q";
} else if (indexOfCustom(a,coord) >= 0){
return "A";
} else if (indexOfCustom(m,coord) >= 0){
return "M";
} else if (indexOfCustom(i,coord) >= 0){
return "I";
} else if (indexOfCustom(r,coord) >= 0){
return "R";
}else{
return "??";
}
}
Output of all answers:
[-2,-2] = R
[-2,-1] = R
[-2,0] = R
[-2,2] = R
[-2,4] = Q
[-1,-2] = R
[-1,-1] = I
[-1,0] = I
[-1,2] = Q
[-1,4] = A
[0,-2] = R
[0,-1] = I
[0,0] = I
[0,2] = I
[0,4] = A
[2,-2] = R
[2,-1] = Q
[2,0] = I
[2,2] = I
[2,4] = A
[4,-2] = Q
[4,-1] = M
[4,0] = M
[4,2] = M
[4,4] = p

How to reduce the number of if

Is there a way to reduce the number of "if" in this code?
function test(input) {
if ((input % 3 == 0) && (input % 5 == 0)) {
return 'fizzbuzz';
} else if (input % 3 == 0) {
return 'fizz';
} else if (input % 5 == 0) {
return 'buzz';
} else {
return '' + input;
}
}
for (var i = 1; i < 100; i++) {
console.log(test(i));
}
You can avoid that by storing the comparison values:
var mod3 = input % 3 == 0;
var mod5 = input % 5 == 0;
... creating a lookup table ...
var outs = [input, "fizz", "buzz", "fizzbuzz"];
... and indexing it ...
return outs[(+mod3) + 2 * (+mod5)];
... no ifs!
You can use the ternary operator:
return ((input%3==0)&&(input%5==0)) ? 'fizz buzz'
: (input%3==0) ? 'fizz'
: (input%5==0) ? 'buzz'
: '' + input;
If you don't want to use if's why not try case syntax?
http://www.w3schools.com/js/js_switch.asp
Alternatively use the JS shorthand for if
so that:
var something;
if (2 + 2 === 4){
something = "Yup!"
} else {
something = "Nope"
}
becomes
var something = 2 + 2 === 4 ? "Yup!" : "Nope";
You can get rid of the first "if" altogether, because 3 and 5 and "fizz" and "buzz" are used in the later ones. You can also wait to return until the end. Something like:
var str = "";
if (input % 3 === 0){
str +="fizz";
}
if (input % 5 === 0 ){
str +="buzz";
} else {
str = input;
}
return str;

Javascript Fizzbuzz Issue

I'm trying to do some simple tests to help further my javascript knowledge (which is quite fresh). Goal 1 is to print numbers from 1-100 that aren't divisible by 5 or 3.
I tried the following:
for (var i = 1; i <= 100; i ++)
{
if (i%3 !== 0 || i%5 !== 0){
console.log(i);
}
}
This logs EVERY number from 1-100, and I can't tell why. Probably the simplest simplest questions here but it's doing my head in!
I think you mean &&, not ||. With ||, you're basically testing to see if the number is not divisible by 3 or by 5 - only if a number is divisible by both do you reject it (in other words, multiples of 15).
The typical answer to FizzBuzz is:
if( i%3 == 0 && i%5 == 0) FizzBuzz
elseif( i % 3 == 0) Fizz
elseif( i % 5 == 0) Buzz
else number
So to get directly to the number you need for i%3==0 to be false AND i%5==0 to be false. Therefore, you want if( i%3 !== 0 && i%5 !== 0)
Here's a quite simple FizzBuzz function that accepts a range of numbers.
function fizzBuzz(from, to) {
for(let i = from; i <= to; i++) {
let msg = ''
if(i % 3 == 0) msg += 'Fizz'
if(i % 5 == 0) msg += 'Buzz'
if(msg.length == 0) msg = i
console.log(msg)
}
}
fizzBuzz(1, 25)
As for a more complex solution, that's one way you could define a higher order function which generates customized FizzBuzz functions (with additional divisors and keywords)
function fizzBuzzFactory(keywords) {
return (from, to) => {
for(let i = from; i <= to; i++) {
let msg = ''
Reflect.ownKeys(keywords).forEach((keyword) => {
let divisor = keywords[keyword]
if(i % divisor == 0) msg += keyword
})
if(msg.length == 0) msg = i
console.log(msg)
}
}
}
// generates a new function
const classicFizzBuzz = fizzBuzzFactory({ Fizz: 3, Buzz: 5 })
// accepts a range of numbers
classicFizzBuzz(1, 25)
const extendedFizzBuzz = fizzBuzzFactory({ Fizz: 3, Buzz: 5, Bazz: 7, Fuzz: 11 })
extendedFizzBuzz(1, 25)
I attacked this the same was as Niet the Dark Absol:
for (var n = 1; n <= 100; n++) {
if (n % 3 == 0 && n % 5 == 0)
console.log("FizzBuzz");
else if (n % 3 == 0)
console.log("Fizz");
else if (n % 5 == 0)
console.log("Buzz");
else
console.log(n);
}
However, you can also do it this way:
for (var n = 1; n <= 100; n++) {
var output = "";
if (n % 3 == 0)
output += "Fizz";
if (n % 5 == 0)
output += "Buzz";
console.log(output || n);
}
One of the hardest parts of learning JavaScript - or any language - for me is understanding solutions can come in many ways. I like the first example more, but it's always good to keep thinking and look at other options.

JavaScript if statement test for one or the other but not both

Hello fellow StackOverflowers. I'm have a brain fart right now, and I cannot seem to figure this out.
I have the following code
if ((n % 3 === 0 || n % 5 === 0) &&( n % 3 !== 0 && n % 5 !== 0))
{
return true;
}
else {
return false;
}
Basically I need to test if the number is a multiple of 3 || 5 but not a multiple of both.
However when I enter any number I enter (whether it is multiple of 3 || 5 || both) the test always fails. I would have thought this was able to be performed in one statement.
This code though does work fine.
if (n % 3 === 0 || n % 5 === 0)
{
if( n % 3 === 0 && n % 5 === 0)
{
return false;
}
else {
return true;
}
}
else {
return false;
}
But I'm wondering what I am missing in the first test. I'd like all the test to be in one like, but like I said I'm having a brain fart and cannot figure out what I'm missing.
You can use the XOR operator, alternatively
return (n % 3 === 0 ^ n % 5 === 0);
If it is divisible by both 3 and 5, it'll be divisible by 15.
Please try the following condition
if ((n % 3 === 0 || n % 5 === 0) && ( n % 15 !== 0))
change
if ((n % 3 === 0 || n % 5 === 0) &&( n % 3 !== 0 && n % 5 !== 0))
to
if ((n % 3 === 0 || n % 5 === 0) && !(n % 3 === 0 && n % 5 === 0))
The first part of your logic is to determine if the number in question is a multiple of 3 or 5 whereas the second SHOULD be about wether only one of them is. So... I changed the second part to see if both match it and then I NOT'ed that.
It should be: if ((n % 3 === 0 || n % 5 === 0) &&( n % 3 !== 0 || n % 5 !== 0))
return (n % 3 === 0 && !(n % 5 === 0)) || (n % 5 === 0 && !(n % 3 === 0));
(untested)
Your second check is wrong:
if ((n % 3 === 0 || n % 5 === 0) &&**( n % 3 !== 0 && n % 5 !== 0)**)
Change it to:
(! (n%3 === 0 && n % 5 === 0 ) )
This is a short version of XOR implementation using conditional statement in javascript
if((n % 3 === 0)? (n % 5 !== 0) : (n % 5 === 0)) {
...
}
or you can also compare in this way, checking when the two conditions, when evaluated as boolean, return different values (one is true and other is false or vice-versa)
if( (n % 3 === 0) !== (n % 5 === 0)) {
...
}
so this code can be written really short

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