Develop Reference

Javascript function returning 'undefined'

I've written a a function which takes score as parameter and should return the letter grade.
There are some conditions to be followed while writing the code. ie: return 'A' if 25 < score <= 30 return 'B' if 20 < score <= 25 and so on. So I wanted to do this by omitting a whole lot of if-else's. As I'm new to javascript this is all I could come up with:
// This function takes Nested arrays and a single number,
// which checks its availability in
// the inside array and then return the index of the array
function my_index(arr, score) {
for (const [index, elem] of arr.entries()) {
if (elem.includes(score)) {
return index;
}
}
}
// function to get letter grade
function getGrade(score) {
let grade;
var gradeDict = {
'A': [26, 27, 28, 29, 30],
'B': [21, 22, 23, 24, 25],
'C': [16, 17, 18, 19, 20],
'D': [11, 12, 13, 14, 15],
'E': [6, 7, 8, 9, 10],
'F': [0, 1, 2, 3, 4, 5]
}
var keys = Object.keys(gradeDict);
var values = [Object.values(gradeDict)]
grade = keys[my_index(values, score)]
return grade;
}
The first function works fine. It returns the index of nested array. But the main function getGrade happens to return 'Undefined'. Can't think of a better solution than this to reduce a bunch of ugly if-elses.
var question = {
'1st': 'Can anybody help me get this done?',
'2nd': 'Is there any better way to do this?'
}

Is there a better way to write this?
I'd do:
function getLetterGrade(score) {
return ['F', 'F', 'E', 'D', 'C', 'B', 'A'][Math.ceil(score / 5)];
}
(F occurs twice because more scores map to F than to other grades)
It may be a bit cryptic, but is easier to tune should the possible score ever change.

Remove the outer [] array of the Object.values. Object.values already returns values in array.
from
var values = [Object.values(gradeDict)];
to
var values = Object.values(gradeDict);
working example:
function my_index(arr, score) {
for (const [index, elem] of arr.entries()) {
if (elem.includes(score)) {
return index;
}
}
}
function getGrade(score) {
let grade;
var gradeDict = {
A: [26, 27, 28, 29, 30],
B: [21, 22, 23, 24, 25],
C: [16, 17, 18, 19, 20],
D: [11, 12, 13, 14, 15],
E: [6, 7, 8, 9, 10],
F: [0, 1, 2, 3, 4, 5],
};
var keys = Object.keys(gradeDict);
var values = Object.values(gradeDict);
grade = keys[my_index(values, score)];
return grade;
}
console.log(getGrade(5));
console.log(getGrade(25));
Alternate solution
function getGrade(score) {
let grade;
var gradeDict = {
A: [26, 27, 28, 29, 30],
B: [21, 22, 23, 24, 25],
C: [16, 17, 18, 19, 20],
D: [11, 12, 13, 14, 15],
E: [6, 7, 8, 9, 10],
F: [0, 1, 2, 3, 4, 5],
};
for (let key in gradeDict) {
if (gradeDict[key].includes(score)) return key;
}
return "Not found";
}
console.log(getGrade(5));
console.log(getGrade(25));

I like the ceil solution proposed earlier, but here is another general solution in case it's helpful:
function grade(score) {
if (score < 0 || score > 30) throw RangeError(`Score ${score} out of range`);
for (let ii = 5; ii >= 0; ii--) {
if (score > 5*ii) return String.fromCharCode(70 - ii);
}
return 'F';
}
console.log(0, '=>', grade(0)) // F
console.log(4, '=>', grade(4)) // F
console.log(6, '=>', grade(6)) // E
console.log(10, '=>', grade(10)) // E
console.log(27, '=>', grade(27)) // A
console.log(30, '=>', grade(30)) // A

Create a function that accepts a string and groups repeated values

Create a function that accepts a string and groups repeated values. The groups should have the following structure: [[value, first_index, last_index, times_repeated], ..., [value, first_index, last_index, times_repeated]].
value: Character being assessed.
first_index: Index of characters first appearance.
last_index: Index of characters last appearance.
times_repeated: Number of consecutive times character repeats.
Examples
findRepeating("a") ➞ [["a", 0, 0, 1]]
findRepeating("aabbb") ➞ [["a", 0, 1, 2], ["b", 2, 4, 3]]
findRepeating("1337") ➞ [["1", 0, 0, 1], ["3", 1, 2, 2], ["7", 3, 3, 1]]
findRepeating("aabbbaabbb") ➞ [["a", 0, 1, 2], ["b", 2, 4, 3], ["a", 5, 6, 2], ["b", 7, 9, 3]]
I am able to do it for unique characters.
But unable to do it for
Number of consecutive times character repeats
MY CODE
function findRepeating(str) {
let unique = [...new Set([...str])]
return unique.map(x=>[x,str.indexOf(x),str.lastIndexOf(x),[...str].filter(a=>a==x).length])
}
EXPECTED RESULT
Test.assertSimilar(findRepeating(''), [])
Test.assertSimilar(findRepeating('a'), [['a', 0, 0, 1]])
Test.assertSimilar(findRepeating('1337'), [['1', 0, 0, 1], ['3', 1, 2, 2], ['7', 3, 3, 1]])
Test.assertSimilar(findRepeating('aabbb'), [['a', 0, 1, 2], ['b', 2, 4, 3]])
Test.assertSimilar(findRepeating('addressee'), [['a', 0, 0, 1], ['d', 1, 2, 2], ['r', 3, 3, 1], ['e', 4, 4, 1], ['s', 5, 6, 2], ['e', 7, 8, 2]])
Test.assertSimilar(findRepeating('aabbbaabbb'), [['a', 0, 1, 2], ['b', 2, 4, 3], ['a', 5, 6, 2], ['b', 7, 9, 3]])
Test.assertSimilar(findRepeating('1111222233334444'), [['1', 0, 3, 4], ['2', 4, 7, 4], ['3', 8, 11, 4], ['4', 12, 15, 4]])
Test.assertSimilar(findRepeating('1000000000000066600000000000001'), [['1', 0, 0, 1], ['0', 1, 13, 13], ['6', 14, 16, 3], ['0', 17, 29, 13], ['1', 30, 30, 1]])
ACTUAL RESULT
Test Passed: Value == '[]'
Test Passed: Value == "[['a', 0, 0, 1]]"
Test Passed: Value == "[['1', 0, 0, 1], ['3', 1, 2, 2], ['7', 3, 3, 1]]"
Test Passed: Value == "[['a', 0, 1, 2], ['b', 2, 4, 3]]"
FAILED: Expected: "[['a', 0, 0, 1], ['d', 1, 2, 2], ['r', 3, 3, 1], ['e', 4, 4, 1], ['s', 5, 6, 2], ['e', 7, 8, 2]]", instead got: "[['a', 0, 0, 1], ['d', 1, 2, 2], ['r', 3, 3, 1], ['e', 4, 8, 3], ['s', 5, 6, 2]]"
FAILED: Expected: "[['a', 0, 1, 2], ['b', 2, 4, 3], ['a', 5, 6, 2], ['b', 7, 9, 3]]", instead got: "[['a', 0, 6, 4], ['b', 2, 9, 6]]"
Test Passed: Value == "[['1', 0, 3, 4], ['2', 4, 7, 4], ['3', 8, 11, 4], ['4', 12, 15, 4]]"
FAILED: Expected: "[['1', 0, 0, 1], ['0', 1, 13, 13], ['6', 14, 16, 3], ['0', 17, 29, 13], ['1', 30, 30, 1]]", instead got: "[['1', 0, 30, 2], ['0', 1, 29, 26], ['6', 14, 16, 3]]"
function findRepeating(str) {
let unique = [...new Set([...str])]
return unique.map(x=>[x,str.indexOf(x),str.lastIndexOf(x),[...str].filter(a=>a==x).length])
}
console.log("Fails ",JSON.stringify(findRepeating('addressee')),"\nexpected", `[['a',0,0,1],['d',1,2,2],['r',3,3,1],['e',4,4,1],['s',5,6,2],['e',7,8,2]]`)
console.log("Fails ",JSON.stringify(findRepeating('aabbbaabbb')),"\nexpected", `[['a',0,1,2],['b',2,4,3],['a',5,6,2],['b',7,9,3]]`)
console.log("Passes ",JSON.stringify(findRepeating('1111222233334444')),"\nexpected", `[['1',0,3,4],['2',4,7,4],['3',8,11,4],['4',12,15,4]]`)
console.log("Fails ",JSON.stringify(findRepeating('1000000000000066600000000000001')),"\nexpected", `[['1',0,0,1],['0',1,13,13],['6', 14,16,3],['0',17,29,13],['1',30,30,1]]`)

You could take an array of same characters with a regular expression which looks for a character and same following onces as a group and map the wanted information.
function findRepeating(string) {
var i = -1;
return (string.match(/(.)\1*/g) || []).map(s => [s[0], ++i, i += s.length - 1, s.length]);
}
console.log(findRepeating("")); // []
console.log(findRepeating("a")); // [["a", 0, 0, 1]]
console.log(findRepeating("aabbb")); // [["a", 0, 1, 2], ["b", 2, 4, 3]]
console.log(findRepeating("1337")); // [["1", 0, 0, 1], ["3", 1, 2, 2], ["7", 3, 3, 1]]
console.log(findRepeating("aabbbaabbb")); // [["a", 0, 1, 2], ["b", 2, 4, 3], ["a", 5, 6, 2], ["b", 7, 9, 3]]

Your code assumes that each group is about a different character. As soon as you have two groups with the same character, things like lastIndex will give the wrong result.
Just use a plain for-loop.
function findRepeating(str) {
let result = [];
let start = 0;
for (let i = 0; i < str.length; i++) {
if (str[i] !== str[i+1]) {
result.push([str[i], start, i, i-start+1]);
start = i+1;
}
}
return result;
}
console.log(findRepeating(''), [])
console.log(findRepeating('a'), [['a', 0, 0, 1]])
console.log(findRepeating('1337'), [['1', 0, 0, 1], ['3', 1, 2, 2], ['7', 3, 3, 1]])
console.log(findRepeating('aabbb'), [['a', 0, 1, 2], ['b', 2, 4, 3]])
console.log(findRepeating('addressee'), [['a', 0, 0, 1], ['d', 1, 2, 2], ['r', 3, 3, 1], ['e', 4, 4, 1], ['s', 5, 6, 2], ['e', 7, 8, 2]])

check even number in mutidimensional array

Hi i have a problem when code, I want to check an even number in multidimensional array and then change to 'X' if there are even numbers in row or column more than equals to 3 times appear but I change it all to 'X' eventhough it's less than 3. my code like this :
function evenNumbers(numbers){
for(var i = 0; i < numbers.length; i++){
for(var j = 0; j < numbers[i].length; j++){
if(numbers[i][j] % 2 == 0){
numbers[i][j] = 'X'
}
}
}
return numbers
}
console.log(evenNumbers([
[1, 2, 4, 6, 5],
[6, 17, 8, 11, 10],
[8, 11, 10, 18, 16],
[18, 12, 19, 27, 21],
[22, 10, 12, 22, 12]
]));
expected output :
[1, 'X', 'X', 'X', 5],
['X', 17, 'X', 11, 10],
['X', 11, 'X', 'X', 'X'],
['X', 12, 19, 27 , 21],
[''X, 'X', 'X', 'X', 'X']
what I got :
[ [ 1, 'X', 'X', 'X', 5 ],
[ 'X', 17, 'X', 11, 'X' ],
[ 'X', 11, 'X', 'X', 'X' ],
[ 'X', 'X', 19, 27, 21 ],
[ 'X', 'X', 'X', 'X', 'X' ] ]
Thanks, in advance
Help me with no ES6 built-in just regular JS, please. Thanks again

You could use some to make the check, then map
const arr = [
[1, 2, 4, 6, 5],
[6, 17, 8, 11, 10],
[8, 11, 10, 18, 16],
[18, 12, 19, 27, 21],
[22, 10, 12, 22, 12]
];
function xEvens(arr) {
return arr.map(row => {
let i = 0;
let shouldChange = row.some(n => n % 2 === 0 && ++i >= 3);
return shouldChange ? row.map(n => n % 2 === 0 ? 'X' : n) : row;
});
}
console.log(xEvens(arr));
Pre es6 version
var arr = [
[1, 2, 4, 6, 5],
[6, 17, 8, 11, 10],
[8, 11, 10, 18, 16],
[18, 12, 19, 27, 21],
[22, 10, 12, 22, 12]
];
function xEvens(arr) {
return arr.map(function(row) {
var i = 0;
var shouldChange = row.some(function(n) {
return n % 2 === 0 && ++i >= 3;
});
return shouldChange ? row.map(function(n) {
return n % 2 === 0 ? 'X' : n
}) : row;
});
}
console.log(xEvens(arr));

You can try following approach:
Idea:
Loop on array and return an array where X is replaced for even numbers.
Keep a track of count of replacements.
If count matches the threshold, return this new array.
If not, return the original array.
This way you will not need an extra loop just to check the validity for replacement.
function replaceEvensWithCondition(arr, minCount, replaceChar) {
return arr.map(function(row) {
var count = 0;
var updatedArray = row.map(function(n) {
var isEven = n % 2 === 0;
count += +isEven;
return isEven ? replaceChar : n;
});
return count >= minCount ? updatedArray : row
});
}
var arr = [ [1, 2, 4, 6, 5], [6, 17, 8, 11, 10], [8, 11, 10, 18, 16], [18, 12, 19, 27, 21], [22, 10, 12, 22, 12] ];
console.log(replaceEvensWithCondition(arr, 3, 'X'));

I'm having trouble trying to splice an array

Hell:
I have been pulling my hair out over this. I'm trying to splice a multidimensional array I want to delete the index that of row that has a 0 and then push zero to the end. I'm able to push zero to the end but the 0 in index column 2 position 2 won't delete. I've tried every thing and thought I could ask for help to point me in the right direction. I really need to get this' Here is my code and I appreciate any help.
(function() {
'use strict';
var data = [
['e', 0, 1, 2, 3, 4],
['a', 54312, 235, 5, 15, 4],
['a', 6, 7, 8, 9, 232],
['a', 54, 11235, 345, 5, 6],
['b', 0, 1, 2, 3, 4],
['b', 54312, 235, 5, 15, 4],
['c', 62, 15, 754, 93, 323],
['d', 27, 11235, 425, 18, 78],
['d', 0, 1, 2, 3, 4],
['d', 54312, 235, 5, 15, 4],
['e', 6, 7, 8, 9, 232],
['e', 54, 11235, 345, 5, 6],
['e', 0, 1, 2, 3, 4],
['e', 54312, 235, 5, 15, 4],
['e', 62, 15, 754, 93, 323],
['e', 27, 11235, 425, 18, 78]
];
//Create a HTML Table element.
var table = document.createElement("TABLE");
var somedata = document.createElement("TD");
//Get the count of columns.
var columnCount = data[0].length;
var count = 0;
//Add the data rows.
for (var i = 0; i < data.length; i++) {
var row = table.insertRow(-1);
for (var j = 0; j < columnCount; j++) {
var cell = row.insertCell(-1);
cell.innerHTML = data[i][j];
cell.innerHtml = myZero;
var myZero = data[i][j]
if (myZero === 0) {
console.log(i, j, cell);
console.log("is equal");
console.log(data[myZero].splice(2, 1));
data[myZero].push(0);
}
}
}
var dvTable = document.getElementById("dvTable");
dvTable.innerHTML = "";
dvTable.appendChild(table);
})();
table {
border-collapse: collapse;
border-left: 1px solid #999999;
border-top: 1px solid #999999;
}
td {
border-right: 1px solid #999999;
border-bottom: 1px solid #999999;
}
<div id="dvTable"></div>
Thanking you in advance
PHD

You had some stuff out of order and your splice was referencing static values so i always spliced the third item in the array (position 2). you were also always pushing the 0 into the first array in the array of arrays (data[myZero].push(0););
(function() {
'use strict';
var data = [
['e', 0, 1, 2, 3, 4],
['a', 54312, 235, 5, 15, 4],
['a', 6, 7, 8, 9, 232],
['a', 54, 11235, 345, 5, 6],
['b', 0, 1, 2, 3, 4],
['b', 54312, 235, 5, 15, 4],
['c', 62, 15, 754, 93, 323],
['d', 27, 11235, 425, 18, 78],
['d', 0, 1, 2, 3, 4],
['d', 54312, 235, 5, 15, 4],
['e', 6, 7, 8, 9, 232],
['e', 54, 11235, 345, 5, 6],
['e', 0, 1, 2, 3, 4],
['e', 54312, 235, 5, 15, 4],
['e', 62, 15, 754, 93, 323],
['e', 27, 11235, 425, 18, 78]
];
//Create a HTML Table element.
var table = document.createElement("TABLE");
var somedata = document.createElement("TD");
//Get the count of columns.
var columnCount = data[0].length;
var count = 0;
//Add the data rows.
for (var i = 0; i < data.length; i++) {
var row = table.insertRow(-1);
for (var j = 0; j < columnCount; j++) {
var myZero = data[i][j]
if (myZero === 0) {
console.log(i, j, cell);
console.log("is equal");
console.log(data[i].splice(j, 1));
data[i].push(0);
}
var cell = row.insertCell(-1);
cell.innerHTML = data[i][j];
cell.innerHtml = myZero;
}
}
var dvTable = document.getElementById("dvTable");
dvTable.innerHTML = "";
dvTable.appendChild(table);
})();
<div id="dvTable"></div>

Output multi-dimensional arrays

I currently have the following array set up:
var TicketInfo =
{
t1: {
1: [7, 12, 35,39,41, 43],
2: [7, 15, 20,34,45, 48],
3: [3, 7, 10, 13, 22, 43],
4: [2, 4, 5,23,27, 33]
},
t2: {
1: [10, 12, 17,44,48, 49],
2: [13, 15, 17, 18, 32, 39],
3: [16, 17, 20, 45, 48, 49],
4: [6, 16, 18, 21, 32, 40]
}
}
What I want to do is iterate through these to bring back the arrays under.
As a test I've tried something like this:
for(t in TicketInfo["t1"])
{
i++;
Write(t.i);
}
But it's obviously not working how I want it to.
Any ideas?
I want to be able to output the arrays like [7, 12, 35,39,41, 43]
Thanks

var TicketInfo =
{
t1: {
1: [7, 12, 35,39,41, 43],
2: [7, 15, 20,34,45, 48],
3: [3, 7, 10, 13, 22, 43],
4: [2, 4, 5,23,27, 33]
},
t2: {
1: [10, 12, 17,44,48, 49],
2: [13, 15, 17, 18, 32, 39],
3: [16, 17, 20, 45, 48, 49],
4: [6, 16, 18, 21, 32, 40]
}
}
for(var j in TicketInfo )
{
for(var p in TicketInfo[j] )
{
for(var i = 0; i < TicketInfo[j][p].length; i++ )
{
console.log(TicketInfo[j][p][i]);
}
}
}​
http://jsfiddle.net/J6rTj/

If you're here from google trying to find a way to do a quick print for debugging, here's a one liner for you:
console.log(myArray.join("\n"))
Example:
var myArray = [[1,2,3],[4,5,6],[7,8,9]];
console.log(myArray.join("\n"));
Output:
1,2,3
4,5,6
7,8,9
Example with proper brackets:
var myArray = [[1,2,3],[4,5,6],[7,8,9]];
console.log("[[" + myArray.join("],\n[") + "]]");
Output:
[[1,2,3],
[4,5,6],
[7,8,9]]
Answer to OP's question:
obj = {
1: [7, 12, 35,39,41, 43],
2: [7, 15, 20,34,45, 48],
3: [3, 7, 10, 13, 22, 43],
4: [2, 4, 5,23,27, 33],
}
var keys = Object.keys(obj);
keys.sort();
console.log(keys);
var listFromObj = []
for (var i = 0; i < keys.length; i++) {
if (obj.hasOwnProperty(keys[i])) listFromObj.push(obj[keys[i]]);
}
console.log("[" + listFromObj.join("]\n[") + "]");
Output:
[7,12,35,39,41,43]
[7,15,20,34,45,48]
[3,7,10,13,22,43]
[2,4,5,23,27,33]

The syntax is TicketInfo["t1"]["1"][0].
That example will give you 7.
TicketInfo["t1"]["1"] will give you the array you're after at the base of your question.

In your code t just represents the key.
Try following code:
var TicketInfo =
{
t1: {
1: [7, 12, 35,39,41, 43],
2: [7, 15, 20,34,45, 48],
3: [3, 7, 10, 13, 22, 43],
4: [2, 4, 5,23,27, 33]
},
t2: {
1: [10, 12, 17,44,48, 49],
2: [13, 15, 17, 18, 32, 39],
3: [16, 17, 20, 45, 48, 49],
4: [6, 16, 18, 21, 32, 40]
}
}
for(t in TicketInfo["t1"])
{
i++;
console.log(TicketInfo["t1"][t]);
}

Do I understand that you want to output entire table in order? Since you use objects on t1/t2 level, you'll have to do extra steps for that.
First, see if you can simply replace objects with real arrays:
var TicketInfoArrays = {
t1: [
[7, 12, 35,39,41, 43],
[7, 15, 20,34,45, 48],
[3, 7, 10, 13, 22, 43],
[2, 4, 5,23,27, 33]
]
}
var t1 = TicketInfoArrays.t1
for(var idx = 0, len = t1.length; idx<len; idx++){
var line = idx+": ["
var nested = t1[idx]
for(var idx2 = 0, len2 = nested.length; idx2<len2; idx2++){
line += ((idx2 > 0 ? ', ':'') + nested[idx2])
}
console.log(line + ']')
}
If that's somehow impossible, but you sure that keys in those objects always start at some specific number and go ascending without gaps, you can simply itreate over properties until you hit empty element:
var TicketInfo = {
t1: {
1: [7, 12, 35,39,41, 43],
2: [7, 15, 20,34,45, 48],
3: [3, 7, 10, 13, 22, 43],
4: [2, 4, 5,23,27, 33]
}
}
var t1 = TicketInfo.t1
var idx = 1
var nested
while(nested = t1[idx]){
var line = idx+": ["
var nested = t1[idx]
for(var idx2 = 0, len2 = nested.length; idx2<len2; idx2++){
line += ((idx2 > 0 ? ', ':'') + nested[idx2])
}
console.log(line + ']')
idx++
}
Finally, if you can't guarantee even that, you will have to manually collect all keys, sort them and then iterate over this sorted list.
var TicketInfoUnordered = {
t1: {
8: [7, 12, 35,39,41, 43],
20: [7, 15, 20,34,45, 48],
45: [3, 7, 10, 13, 22, 43],
3: [2, 4, 5,23,27, 33]
}
}
var t1 = TicketInfoUnordered.t1
var keys = []
for(key in t1){
if(t1.hasOwnProperty(key)){ keys.push(key) }
}
keys.sort(function(a, b){ return a - b })
for(var idx = 0, len = keys.length; idx<len; idx++){
var line = keys[idx]+": ["
var nested = t1[keys[idx]]
for(var idx2 = 0, len2 = nested.length; idx2<len2; idx2++){
line += ((idx2 > 0 ? ', ':'') + nested[idx2])
}
console.log(line + ']')
}