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I have a JavaScript array of objects which looks like
var myarr = [
{'xx':'2023-01-01,,1'},
{'ss':'2023-01-01,2,1.2'},
{'dd':'2023-01-01,4,'},
{'rr':'2023-01-01,,'},
{'ff':'2023-01-01,,'},
{'gg':'2023-01-01,,'}
];
The array is actually much bigger than that, but I have cut it down for testing purposes, some of my arrays are thousands of lines long
Each object contains a date and two comma-separated values, although I have some rows which contain 3 or 4 comma separate values
What I need to do, is if any blank comma-separated value is found on any row then get the previous comma separated value from that position to a maximum of 2 times going back, although I may need to change that to a bigger number in the future
So with my example, I would get the following output
var myarr = [
{'xx':'2023-01-01,,1.6'},
{'ss':'2023-01-01,2,1.2'},
{'dd':'2023-01-01,4,1.2'},
{'rr':'2023-01-01,4,1.2'},
{'ff':'2023-01-01,4,'},
{'gg':'2023-01-01,,'}
];
I have tried to solve this with
var myarr = [
{'xx':'2023-01-01,,1'},
{'ss':'2023-01-01,2,1.2'},
{'dd':'2023-01-01,4,'},
{'rr':'2023-01-01,,'},
{'ff':'2023-01-01,,'},
{'gg':'2023-01-01,,'}
];
var maxAttempts = 3;
for (var i = 0; i < myarr.length; i++) {
var obj = myarr[i];
var values = Object.values(obj)[0].split(",");
var date = values[0];
var value1 = values[1];
var value2 = values[2];
for (var j = 1; j <= maxAttempts; j++) {
if (!value1) {
value1 = (myarr[i-j] && Object.values(myarr[i-j])[0].split(",")[1]) || " ";
}
if (!value2) {
value2 = (myarr[i-j] && Object.values(myarr[i-j])[0].split(",")[2]) || " ";
}
if (value1 && value2) {
break;
}
}
console.log(date, value1, value2);
for (var k = 3; k < values.length; k++) {
var value = values[k];
console.log(value);
}
}
but it doesn't seem to provide the expected output.
Can someone help me with what might be wrong?
Maybe you can use something like this.
const myarr = [
{ "xx": "2023-01-01,,1" },
{ "ss": "2023-01-01,2,1.2" },
{ "dd": "2023-01-01,4," },
{ "rr": "2023-01-01,," },
{ "ff": "2023-01-01,," },
{ "gg": "2023-01-01,," }
]
function fillInBlanks(arr, maxLookBack) {
return arr.map((obj, index) => {
const key = Object.keys(obj)[0]
const value = Object.values(obj)[0]
.split(",")
.map((x, n) => {
if (x === "" && index > 0) {
for (let i = index - 1; i >= Math.max(0, index - maxLookBack); --i) {
const prev = Object.values(arr[i])[0].split(",")
if (prev[n] !== "") return prev[n]
}
} else return x
})
return Object.fromEntries([
[key, value.join(",")]
])
})
}
fillInBlanks(myarr, 2).forEach(x => console.log(x))
Here's my attempt. This will also work with any number of values per row.
const maxAttempts = 2;
myarr.reduce((modifiedAccumulation, currentObject, index) => {
const [key, csv] = Object.entries(currentObject)[0];
const splitCsv = csv.split(",");
const modifiedCsv = splitCsv
.reduce((fixedArray, currentElement, csvPos) => {
let numberToUse =
currentElement === ""
? myarr
.slice(Math.max(index - maxAttempts, 0), index)
.reduceRight((proposedNum, currentPastObj) => {
if (proposedNum !== "") return proposedNum;
let candidate =
Object.entries(currentPastObj)[0][1].split(",")[csvPos];
return candidate !== "" ? candidate : "";
}, "")
: currentElement;
return [...fixedArray, numberToUse];
}, [])
.join(",");
return [...modifiedAccumulation, { [key]: modifiedCsv }];
}, []);
This approach creates a 'window' array containing the last few entries, which is used to look up prior column values.
const myarr = [{"xx":"2023-01-01,,1"},{"ss":"2023-01-01,2,1.2"},{"dd":"2023-01-01,4,"},{"rr":"2023-01-01,,"},{"ff":"2023-01-01,,"},{"gg":"2023-01-01,,"}]
const windowSize = 2
const w = [], r =
myarr.map(e=>Object.entries(e).flatMap(([k,v])=>[k,...v.split(',')]))
.map(a=>(
w.unshift(a) > windowSize+1 && w.pop(),
a.map((_,i)=>w.find(x=>x[i])?.[i])
)).map(([k,...v])=>[k,v.join()]
).map(i=>Object.fromEntries([i]))
console.log(r)
I want to write a function to get all of the permutations of the array elements.
I do not want you to write the function for me! I want to work through it myself. Please do me the favor of letting me work through it.
Input: [1,2,3]
Output: 123, 132, 213, 231, 312, 321.
I believe the output should be an array of length factorial(input.length). So if the input is a three element array, the output should contain 3*2 elements. A four element input array would result in an array length of 24 (4*3*2) elements, with each element of the input array being the first element of a six element array.
Input: ['a','bo']
Output: ['abo', 'boa']
Input: [1,2,3,4]
Output:
[
1234 1243 1324 1342 1423 1432
2134 2143 2314 2341 2413 2431
3124 3142 3214 3241 3412 3421
4123 4132 4213 4231 4312 4321
]
(commas omitted from the output pseudocode).
Here is what I have so far. It isn't working. I think I need a nested loop.
function getWordPermutations(words) {
const len = words.length;
const factorial = n => !(n > 1) ? 1 : factorial(n - 1) * n;
let r = [words.join("")];
for(let i = 0; i < words.length; i++) {
let tmp = words[i];
let nextIndex = words[i+1] ? i+1 : words.length-1 - i;
words[i] = words[nextIndex];
words[nextIndex] = tmp;
r.push(words.join(""))
}
console.log(r);
return r;
}
getWordPermutations([1,2,3]); // Result: ["123", "213", "231", "132"]
It doesn't complete all of the permutations. Can you ask me some questions to get me to think about it.
Taken from, https://github.com/mission-peace/interview/blob/master/src/com/interview/recursion/StringPermutation.java
and re-implemented in Javascript.
function permute(input) {
let countMap = new Map();
for (ch of input.split("")) {
//console.log(ch, countMap.has(ch));
if (countMap.has(ch)) {
let inc = countMap.get(ch) + 1;
countMap.set(ch, inc);
} else {
countMap.set(ch, 1);
}
}
//console.log(countMap);
str = new Array(countMap.size); //char[countMap.size()];
count = new Array(countMap.size); //int[countMap.size];
index = 0;
for (let [key, val] of countMap.entries()) {
//console.log(key, val);
str[index] = key;
count[index] = val;
index++;
}
//console.log(str, count);
resultList = new Array();
result = new Array(input.length); //char[input.length]
permuteUtil(str, count, result, 0, resultList);
return resultList;
}
function permuteUtil(str, count, result, level, resultList) {
if (level == result.length) {
resultList.push(result.join("")); //resultList.add(new String(result));
return;
}
for (let i = 0; i < str.length; i++) {
if (count[i] == 0) {
continue;
}
result[level] = str[i];
count[i]--;
permuteUtil(str, count, result, level + 1, resultList);
count[i]++;
}
}
permute("AABC").forEach((s) => console.log(s));
.as-console-wrapper { max-height: 100% !important; top: 0; }
The output is as expected:
AABC
AACB
ABAC
ABCA
ACAB
ACBA
BAAC
BACA
BCAA
CAAB
CABA
CBAA
If you want a dynamic input and output via HTML and to allow more than just single characters then (https://codepen.io/Alexander9111/pen/abOMpgz):
For your specific examples, we just need to enter a comma-separated list like "1,2,3" into the HTML input tag:
function permute(input) {
let countMap = new Map();
const input_arr = input.split(",");
for (ch of input_arr) {
//console.log(ch, countMap.has(ch));
if (countMap.has(ch)) {
let inc = countMap.get(ch) + 1;
countMap.set(ch, inc);
} else {
countMap.set(ch, 1);
}
}
//console.log(countMap);
str = new Array(countMap.size); //char[countMap.size()];
count = new Array(countMap.size); //int[countMap.size];
index = 0;
for (let [key, val] of countMap.entries()) {
//console.log(key, val);
str[index] = key;
count[index] = val;
index++;
}
//console.log(str, count);
resultList = new Array();
result = new Array(input_arr.length); //char[input.length]
permuteUtil(str, count, result, 0, resultList);
return resultList;
}
function permuteUtil(str, count, result, level, resultList) {
if (level == result.length) {
resultList.push(result.join(',')); //resultList.add(new String(result));
return;
}
for (let i = 0; i < str.length; i++) {
if (count[i] == 0) {
continue;
}
result[level] = str[i];
count[i]--;
permuteUtil(str, count, result, level + 1, resultList);
count[i]++;
}
}
//permute("1,2,3").forEach((s) => console.log(s));
const output_tag = document.getElementById("output");
const input_tag = document.getElementById("input");
const go = document.getElementById("go");
go.addEventListener("click", (e) => {
output_tag.innerText = permute(String(input_tag.value)).join("\n");
});
output_tag.innerText = permute(String(input_tag.value)).join("\n");
<h3>Input (comma separated):</h3>
<input id="input" value="1,2,3">
<br /><br />
<button id="go">Go</button>
<br>
<h3>Output:</h3>
<div id="output"></div>
my question is actually similar to: Extracting the most duplicate value from an array in JavaScript (with jQuery)
I Found this but it always return one value only which is 200.
var arr = [100,100,200,200,200,300,300,300,400,400,400];
var counts = {}, max = 0, res;
for (var v in arr) {
counts[arr[v]] = (counts[arr[v]] || 0) + 1;
if (counts[arr[v]] > max) {
max = counts[arr[v]];
res = arr[v];
}
}
console.log(res + " occurs " + counts[res] + " times");
pls help me to return values not just one...
The result is should like this:
200,300,400
.
pls help thank you!
You have to iterate your counts to find the max occurred result.
var arr = [100,100,200,200,200,300,300,300,400,400,400];
var counts = {}, max = 0, res;
for (var v in arr) {
counts[arr[v]] = (counts[arr[v]] || 0) + 1;
if (counts[arr[v]] > max) {
max = counts[arr[v]];
res = arr[v];
}
}
var results = [];
for (var k in counts){
if (counts[k] == max){
//console.log(k + " occurs " + counts[k] + " times");
results.push(k);
}
}
console.log(results);
Create a Object iterating the arry containing the indexes of most repeated values, like below
var arr = [100,100,200,200,200,300,300,300,400,400,400];
valObj = {}, max_length = 0, rep_arr = [];
arr.forEach(function(el,i){
if(valObj.hasOwnProperty(el)){
valObj[el] += 1;
max_length = (valObj[el] > max_length) ? valObj[el] : max_length
}
else{
valObj[el] = 1;
}
});
Object.keys(valObj).forEach(function(val){
(valObj[val] >= max_length) && (rep_arr.push(val))
});
console.log(rep_arr);
After the object is created with key as array value and value as array indexes of that value, you can play/parse that. Hope this helps.
Iterating an array using for..in is not a good idea. Check this link for more information.
Hopefully below snippet will be useful
var arr = [100, 100, 200, 200, 200, 300, 300, 300, 400, 400, 400];
//Use a reduce fuction to create an object where 100,200,300
// will be keys and its value will the number of times it has
//repeated
var m = arr.reduce(function(i, v) {
if (i[v] === undefined) {
i[v] = 1
} else {
i[v] = i[v] + 1;
}
return i;
}, {});
// Now get the maximum value from that object,
//getMaxRepeated will be 3 in this case
var getMaxRepeated = Math.max(...Object.values(m));
//An array to hold elements which are repeated 'getMaxRepeated' times
var duplicateItems = [];
// now iterate that object and push the keys which are repeated
//getMaxRepeated times
for (var keys in m) {
if (m[keys] === getMaxRepeated) {
duplicateItems.push(keys)
}
}
console.log(duplicateItems)
The following would do the trick assuming that all items in arr are numbers:
//added some numbers assuming numbers are not sorted
var arr = [300,400,200,100,100,200,200,200,300,300,300,400,400,400];
var obj = arr.reduce(//reduce arr to object of: {"100":2,"200":4,"300":4,"400":4}
(o,key)=>{//key is 100,200, ... o is {"100":numberOfOccurrences,"200":numberOf...}
o[key] = (o[key])?o[key]+1:1;
return o;
},
{}
);
// obj is now: {"100":2,"200":4,"300":4,"400":4}
//create an array of [{key:100,occurs:2},{key:200,occurs:4}...
var sorted = Object.keys(obj).map(
key=>({key:parseInt(key),occurs:obj[key]})
)//sort the [{key:100,occurs:2},... by highest occurrences then lowest key
.sort(
(a,b)=>
(b.occurs-a.occurs===0)
? a.key - b.key
: b.occurs - a.occurs
);
console.log(
sorted.filter(//only the highest occurrences
item=>item.occurs===sorted[0].occurs
).map(//only the number; not the occurrences
item=>item.key
)
);
Try as following ==>
function getDuplicate( arr ){
let obj = {}, dup = [];
for(let i = 0, l = arr.length; i < l; i++){
let val = arr[i];
if( obj[val] /**[hasOwnProperty]*/ ) {
/**[is exists]*/
if(dup.find(a => a == val) ) continue;
/**[put Unique One]*/
dup.push(val);
continue;
};
/**[hold for further use]*/
obj[val] = true;
}
return dup;
};
Use ==>
getDuplicate([100,100,200,200,200,300,300,300,400,400,400]);
Try the following:
var candles = [100,100,200,200,200,300,300,300,400,400,400];
let tempArray = {}
for (let index = 0; index <= (candles.length - 1); index++) {
let valueToCompare = candles[index];
if (tempArray[valueToCompare]) {
tempArray[valueToCompare] = tempArray[valueToCompare] + 1;
} else {
tempArray[valueToCompare] = 1;
}
}
let highestValue;
Object.values(tempArray).forEach(item => {
if (highestValue === undefined) highestValue = item;
if (highestValue < item) highestValue = item;
});
console.log(highestValue);
I have a string
var stringIHave = "Java$$Java$$jQuery$$Java$$jQuery$$Java$$Java$$Java$$Hibernate$$Java$$Java$$Spring$$Instagram$$jQuery$$jQuery$$";
How to get the count of the number of occurrences of each entry, The occurrence I get, is from a JSON like Java = 8 and etc...
First of all you need to split your srting to array:
var keywordsArr = stringIHave.split( '$$' );
then you need to have an object for example to store counts:
var occur = {};
and then just create simple for loop to count all occurrences:
for( var i = 0; i < keywordsArr.length; i++ ) {
occur[ keywordsArr[ i ] ] = ( occur[ keywordsArr[ i ] ] || 0 ) + 1;
}
now your object occur will have names as keys and count as values.
See jsFiddle demo.
Also as you have at end of your string $$ you maybe will need to remove last item from keywordsArr so just do after split function call:
keywordsArr.pop();
See demo without last element.
So final code will be like:
var stringIHave = "Java$$Java$$jQuery$$Java$$jQuery$$Java$$Java$$Java$$Hibernate$$Java$$Java$$Spring$$Instagram$$jQuery$$jQuery$$",
keywordsArr = stringIHave.split( '$$' ),
occur = {};
keywordsArr.pop();
for( var i = 0; i < keywordsArr.length; i++ ) {
occur[ keywordsArr[ i ] ] = ( occur[ keywordsArr[ i ] ] || 0 ) + 1;
}
for( var key in occur ) {
document.write( key + ' - ' + occur[key] + '<br/>' );
}
I'd suggest the following:
function stringCount(haystack, needle) {
if (!needle || !haystack) {
return false;
}
else {
var words = haystack.split(needle),
count = {};
for (var i = 0, len = words.length; i < len; i++) {
if (count.hasOwnProperty(words[i])) {
count[words[i]] = parseInt(count[words[i]], 10) + 1;
}
else {
count[words[i]] = 1;
}
}
return count;
}
}
console.log(stringCount("Java$$Java$$jQuery$$Java$$jQuery$$Java$$Java$$Java$$Hibernate$$Java$$Java$$Spring$$Instagram$$jQuery$$jQuery$$", '$$'));
JS Fiddle demo.
References:
Object.hasOwnProperty().
parseInt().
String.split().
It's not entirely clear what final objective is. Following creates an object from string that looks like
Object created:
{
"Java": 8,
"jQuery": 4,
"Hibernate": 1,
"Spring": 1,
"Instagram": 1
}
JS:
var str = 'Java$$Java$$jQuery$$Java$$jQuery$$Java$$Java$$Java$$Hibernate$$Java$$Java$$Spring$$Instagram$$jQuery$$jQuery$$';
var arr = str.split('$$')
var obj = {};
for (i = 0; i < arr.length; i++) {
if (arr[i] != '') {
if (!obj[arr[i]]) {
obj[arr[i]] = 0;
}
obj[arr[i]]++;
}
}
You can loop over the object to get all values or simply look up one value
var jQueryOccurences= obj['jQuery'];
DEMO: http://jsfiddle.net/25hBV/1/
Now a days you can do
const str = "Java$$Java$$jQuery$$Java$$jQuery$$Java$$Java$$Java$$Hibernate$$Java$$Java$$Spring$$Instagram$$jQuery$$jQuery$$";
var result = str.split("$$").reduce(function(acc, curr) {
curr && (acc[curr] = (acc[curr] + 1) || 1);
return acc
}, {});
console.log(result);
Split the string into an array, and putting the array into an object takes care of duplicates and counts occurences as key/value pairs in the object, see fiddle!
var stringIHave = "Java$$Java$$jQuery$$Java$$jQuery$$Java$$Java$$Java$$Hibernate$$Java$$Java$$Spring$$Instagram$$jQuery$$jQuery$$",
s = stringIHave.split('$$');
obj = {};
for (var i=s.length; i--;) {
obj[s[i]] = (s[i] in obj) ? obj[s[i]]+1 : 1;
}
// obj.Java == 8
FIDDLE
If you want it short and sweet:
// variable declarations
var arParts = stringIHave.match(/\w+/g),
result = {},
i = 0,
item;
// Copy the array to result object
while (item = arParts[i++]) result[item] = (result[item] || 0 ) + 1;
demo
So I have a multidimensional array like:
myArr = [["venue",2],["venue",16],["inning",2],["inning",4],["inning",32],["hithard", 4]]
I would like to add the similar values up. So in the end I just have:
"venue" = 18, "inning" = 38, and "hithard" = 4.
Can you give me an example of how to accomplish this? Either with Javascript and/or jQuery
Thanks!
I am not sure if you want an array or object. If object, stop it is 1st pass and tmp in below code should return you the object as Object { venue=18, inning=38, hithard=4}.
DEMO
var tmp = {}, keys;
for (var i = 0; i < myArr.length; i++) {
keys = myArr[i][0];
tmp[keys] = (tmp.hasOwnProperty(keys))?
(tmp[keys] + myArr[i][1]):myArr[i][1];
} //tmp - will return you a Object { venue=18, inning=38, hithard=4}
var output = [];
for (keys in tmp) {
output.push([keys, tmp[keys]]);
} //output will return you an array as [["venue", 18],["inning", 38],["hithard", 4]]
myArr = [["venue",2],["venue",16],["inning",2],["inning",4],["inning",32],["hithard", 4]];
values = {};
for (i=0;i<myArr.length;i++){
if ("undefined" == typeof values[myArr[i][0]]) {values[myArr[i][0]] = 0;}
values[myArr[i][0]] += myArr[i][1];
}
arr = [];
query_string = "";
for (i in values) {
// if you want it in an array:
arr.push('"' + i + '" = ' + values[i]);
query_string += (query_string.length ? "&" : "") + i + "=" + values[i];
}
console.log(arr);
DEMO: http://jsfiddle.net/Ta97E/2/
you can use values to create the query string
Check this code:
var final = {};
for (var i in myArr) {
var item = myArr[i];
final[item[0]] = (final[item[0]] || 0) + item[1];
}
console.log(final);
DEMO: http://jsfiddle.net/UVJEb/
Underscore solution:
sums = _.reduce(myArr, function (obj, item) {
obj[item[0]] = (obj[item[0]] || 0) + item[1];
return obj;
}, {});
// sums = {"venue":18,"inning":38,"hithard":4}
A little dirtier in jQuery
sums = {}
$.each(myArr, function (i, value) {
sums[value[0]] = (sums[value[0]] || 0) + value[1];
});
Edit: add jQuery version