I have an simple javascript array that may contain duplicates or maynot contain duplicates.
var names = [
['aaa','pin/test1.html'],
['bbb','pin/test2.html'],
['ttt','test.html'],
['ggg','test.html'],
['yyy','un/777.html'],
['ggg','test3.html'],
['nnn','test3.html'],
['eee','n/777.html'],
['sss','pin/test1.html'],
['xxx','pin/test2.html'],
['ppp','pin/test1.html'],
];
I need to find the duplicate filepath and put their name into new array. If there is no duplicate then assign its name in first and then assign '' after two values. I could point all the codes that I have tried but it doesnt work. I accept jquery solution also. The expected outcome is this.
var outcome = [
[['aaa','sss','ppp'], 'pin/test1.html'],
[['bbb','eee','xxx'], 'pin/test2.html'],
[['ttt','ggg',''], 'test.html'],
[['yyy','',''], 'un/777.html'],
[['ggg','nnn',''], 'test3.html'],
];
What I have tried is this
for (var i = 0; i < arr.length; i++) {
var uniqueNames = [];
$.each(arr[i], function (i, el) {
if ($.inArray(el, uniqueNames) === -1) uniqueNames.push(el);
});
console.log(uniqueNames);
}
You could take a hash table and an array of empty strings and find the next slot for the value.
The array is reduced by taking an object as accumulator and a destructure array as value (the first part of the array) and key (the second part, aka filepath).
Inside of Array#reduce, a property check with the key is made and if undefined, an array with the wanted structure (array with two items, the first is an array with three emty spaces and the key) is being assigned by using a logical nullish assignment ??=.
The next line assigns the value to the next free slot, an item with an empty string.
Finally the accumulator is returned.
To get only an array as result, a conversion of the values of the object takes place.
let names = [['aaa','pin/test1.html'], ['bbb','pin/test2.html'], ['ttt','test.html'], ['ggg','test.html'], ['yyy','un/777.html'], ['ggg','test3.html'], ['nnn','test3.html'], ['eee','n/777.html'], ['sss','pin/test1.html'], ['xxx','pin/test2.html'], ['ppp','pin/test1.html']],
grouped = Object.values(names.reduce((r, [v, k]) => {
r[k] ??= [Array(3).fill(''), k];
r[k][0][r[k][0].indexOf('')] = v;
return r;
}, {}));
console.log(grouped);
.as-console-wrapper { max-height: 100% !important; top: 0; }
const aux = (names) => {
const hash = {};
let max = 0;
names.forEach(ele => {
if (!hash[ele[1]]) hash[ele[1]] = [];
hash[ele[1]].push(ele[0]);
max = Math.max(hash[ele[1]].length, max);
});
return Object.keys(hash).map(ele => [[...hash[ele], ...Array(max -hash[ele].length).fill("")], ele]);
}
var names = [
['aaa','pin/test1.html'],
['bbb','pin/test2.html'],
['ttt','test.html'],
['ggg','test.html'],
['yyy','un/777.html'],
['ggg','test3.html'],
['nnn','test3.html'],
['eee','n/777.html'],
['sss','pin/test1.html'],
['xxx','pin/test2.html'],
['ppp','pin/test1.html'],
];
console.log(aux(names))
This might help
You do not need jQuery for dealing with regular JS structure, you can achieve what you want with a simple code like this:
var names = [['aaa','pin/test1.html'],['bbb','pin/test2.html'],['ttt','test.html'],['ggg','test.html'],['yyy','un/777.html'],['ggg','test3.html'],['nnn','test3.html'],['eee','n/777.html'],['sss','pin/test1.html'],['xxx','pin/test2.html'],['ppp','pin/test1.html'],];
let lengthToFill = 0;
// collecting all the duplicates into a map
const pathMap = {};
names.forEach(name => {
// just in case if you're not familiar with array destructuring
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment
const [pathName, path] = name;
// make sure we have an array to deal with
// just in case you're not familiar with Nullish coalescing operator (??)
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Nullish_coalescing_operator
pathMap[path] = pathMap[path] ?? [];
pathMap[path].push(pathName);
// tracking the max number of elements we're adding into a single entry
lengthToFill = Math.max(lengthToFill, pathMap[path].length);
});
const result = Object.entries(pathMap).map(entry => {
// constructing new array entry based on the data we've collected so far
return [
entry[1].concat(Array(lengthToFill - entry[1].length).fill('')),
entry[0],
];
});
console.log(result);
This solution will work for any number of elements that you'd like to fill the array with ''. It makes sure that the length of final listing is the same for all entries.
Related
I have two lists:
lista_source: 'B10L-A2,AABan38711$B10L-A2,AABan38811$B12A-A,AABan38912$B14-A2,AABan39314$B16B-A,AABan39616$B12A-A,AABan39818$B16L-B,AABan39919$B16L-B,AABan40019$B12A-A,AABan41112'
second_list: 'B10L-A2,B12A-A,B16L-B'
As a result I would like to get the following list (or similar one):
result = [B10L-A2:AABan38711,AABan38811],[B12A-A:AABan38912,AABan41112,AABan39818],[B16L-B:AABan39919,AABan40019]
In short, I'm looking for multiple values for the 2nd lists items.
I tried the filter function and write it to csv file but does not really work.
const first_list_object= first_list.split('$');
const second_list_object= second_list.split(',');
for (let i = 0; i < second_list_object.length; i++) {
let results= first_list_object.filter(x => x.includes(second_list_object[i]));
console.log(results);
writer = csvWriter({ sendHeaders: false });
writer.pipe(fs.createWriteStream(__dirname + '/lista.csv', { flags: 'a' }));
writer.write({
results
});
}
How should I solve it? Is there any better solution than filter?
A javascript object as output. If you need, I can convert this to .csv too.
const lista_source = 'B10L-A2,AABan38711$B10L-A2,AABan38811$B12A-A,AABan38912$B14-A2,AABan39314$B16B-A,AABan39616$B12A-A,AABan39818$B16L-B,AABan39919$B16L-B,AABan40019$B12A-A,AABan41112'
const second_list = 'B10L-A2,B12A-A,B16L-B'
// convert data to arrays
const source = lista_source.split(",")
const second = second_list.split(",")
// filter out source list items (into seperate object value) for each second list item
const res = second.reduce((obj, sec_key) => {
// get item, if string is not exact key name and string includes key name
const filtered = source.filter(key => key !== sec_key && key.includes(sec_key))
return ({...obj, [sec_key]: filtered })
}, {})
console.log(res)
Assuming that structure of the strings are gonna be like in question, I wrote same basic regex to split on and then add them accordingly to object. See if that's what you want.
Edit:
After rereading your question, I realized that comma actually doesn't separate values in your string but dolar sign instead (kinda weird but ok). I also added an if to take only values present in second list.
const lista_source = 'B10L-A2,AABan38711$B10L-A2,AABan38811$B12A-A,AABan38912$B14-A2,AABan39314$B16B-A,AABan39616$B12A-A,AABan39818$B16L-B,AABan39919$B16L-B,AABan40019$B12A-A,AABan41112'
const second_list = 'B10L-A2,B12A-A,B16L-B'.split(',')
const array = lista_source.match(/B[0-9]{2}[A-Z]-[A-Z][0-9]?,[A-Za-z0-9_]{10}/g)
let result = {}
for (let value of array) {
let [key, s] = value.split(',')
// only take keys form contained in second list
if(!second_list.includes(key)){
continue
}
key in result ? result[key] = [s, ...result[key]] : result[key] = [s]
}
console.log(result)
so I want to find unique values from an array.
so for example I have this array:
const mainArr = ['shape-10983', 'size-2364', 'size-7800', 'size-4602', 'shape-11073', 'size-15027', 'size-15030', 'size-15033', 'height-3399', 'height-5884']
so I want to find the first matching value for each unique item.
for example, in the array, I have two strings with the shape prefix, six items with the size prefix, and two items with the height prefix.
so I want to output to be something like
const requiredVal = ["shape-10983", "size-2364", "height-3399"]
I want only the first value from any set of different values.
the simplest solution will be to iterate on the list and storing what you got in a dictionary
function removeSimilars(input) {
let values = {};
for (let value of input) {//iterate on the array
let key = value.splitOnLast('-')[0];//get the prefix
if (!(key in values))//if we haven't encounter the prefix yet
values[key] = value;//store that the first encounter with the prefix is with 'value'
}
return Object.values(values);//return all the values of the map 'values'
}
a shorter version will be this:
function removeSimilars(input) {
let values = {};
for (let value of input)
values[value.splitOnLast('-')[0]] ??= value;
return Object.values(values);
}
You could split the string and get the type and use it aks key for an object along with the original string as value. At result take only the values from the object.
const
data = ['shape-10983', 'size-2364', 'size-7800', 'size-4602', 'shape-11073', 'size-15027', 'size-15030', 'size-15033', 'height-3399', 'height-5884'],
result = Object.values(data.reduce((r, s) => {
const [type] = s.split('-', 1);
r[type] ??= s;
return r;
}, {}));
console.log(result);
If, as you mentioned in the comments, you have the list of prefixes already available, then all you have to do is iterate over those, to find each first element that starts with that prefix in your full list of possible values:
const prefixes = ['shape', 'size', 'height'];
const list = ['shape-10983', 'size-2364', 'size-7800', 'size-4602', 'shape-11073', 'size-15027', 'size-15030', 'size-15033', 'height-3399', 'height-5884']
function reduceTheOptions(list = [], prefixes = [], uniques = []) {
prefixes.forEach(prefix =>
uniques.push(
list.find(e => e.startsWith(prefix))
)
);
return uniques;
}
console.log(reduceTheOptions(list, prefixes));
Try this:
function getRandomSet(arr, ...prefix)
{
// the final values are load into the array result variable
result = [];
const randomItem = (array) => array[Math.floor(Math.random() * array.length)];
prefix.forEach((pre) => {
result.push(randomItem(arr.filter((par) => String(par).startsWith(pre))));
});
return result;
}
const mainArr = ['shape-10983', 'size-2364', 'size-7800', 'size-4602', 'shape-11073', 'size-15027', 'size-15030', 'size-15033', 'height-3399', 'height-5884'];
console.log("Random values: ", getRandomSet(mainArr, "shape", "size", "height"));
I modified the #ofek 's answer a bit. cuz for some reason the ??= is not working in react project.
function removeSimilars(input) {
let values = {};
for (let value of input)
if (!values[value.split("-")[0]]) {
values[value.split("-")[0]] = value;
}
return Object.values(values);
}
create a new array and loop over the first array and check the existing of element before in each iteration if not push it to the new array
I'm working on a problem where I'm mapping through arrays returned from an API call to create an array of graph point objects, however the data returned is unreliable and contains null values. In order to simplify the question, here's a short version of what I have now:
const APITimestamps = ['123','124','125','126','127','128']
const APIPrices = ['22.34','22,45',NULL,NULL,'22.89','22.32']
const chartData = APITimestamps.map((timestamp, index) => {
let graphPoint = {}
graphPoint.timestamp = APITimestamps[index]
graphPoint.price = APIPrices[index]
return graphPoint
}
The map works as is, however I need to rid the chartData of the null values where the API does not have a price some of the timestamps. What I would like to do is backtrack through the indexes of APIPrices being mapped until a non-null value is found, which in the above case would be ['22.34','22,45','22,45','22,45','22.89','22.32']. Any pointers on how to achieve this?
You can use a for loop that iterates backwards from the current index and finds the first non-null value.
const APITimestamps = ['123','124','125','126','127','128']
const APIPrices = ['22.34','22,45',null,null,'22.89','22.32']
const chartData = APITimestamps.map((timestamp, index) => {
let graphPoint = {}
graphPoint.timestamp = APITimestamps[index]
for(let i = index; i >= 0; i--){
if(APIPrices[i] !== null){
graphPoint.price = APIPrices[i];
break;
}
}
return graphPoint
});
console.log(chartData);
I have an assignment which i need to sole but i am really stuck and can't make a progress. The assignment consist in an array of elements like this
const appleHolderLine = ['Rome', 'Ambrosia', 'Rome', 'RedDelicious', 'Akane','RedDelicious', 'SweeTango', 'RedDelicious', 'RedDelicious', 'Opal', 'Winesap', 'RedDelicious', 'Empire', 'RedDelicious', 'Liberty'];
Firstly it is needed to declare a variable lineCount which count for every element of the array and a reference to an object called appleMap.
Than the challenge consist in looping through the array and the elements of the array would be the object keys with no duplicates and the values would be an array of idexes of the specific element place of the array. To give an example how it should look like:
Example:
const appleHolderLine = ['GreenApples', 'RedDelicious','OrangeApples', 'PurpleApples', 'RedDelicious']
console.log (lineCount, appleMap)
Should Log:
5, {'GreenApples':[0], 'RedDelicious': [1,4], 'OrangeApples':[2], 'PurpleApples': [3]}
My progress so far
var lineCount = 0;
var appleMap = {};
for (let i = 0; i < appleHolderLine.length; i++){
lineCount++;
// if element in the array exist in the array
appleMap[appleHolderLine[i]] = [i];
}
Could you give me a hint of how to solve this, i am really stuck.
Basically you can create an empty array the first time and keep pushing like below
var lineCount = 0;
var appleMap = {};
for (let i = 0; i < appleHolderLine.length; i++){
lineCount++;
if(!appleMap[appleHolderLine[i]])
appleMap[appleHolderLine[i]] = []
appleMap[appleHolderLine[i]].push(i);
}
You could use Array.prototype.reduce which is a more advanced construct javascript provides. Please refer to answer by CodeManiac below for the same.
The above answer is to clarify the basic idea and hint on how you could think
Also, lineCount can be obtained by using appleHolderLine.length directly.
You don't need an extra variable ( Line count ) here, simply loop over the value use, use the index to access value, check if there's nothing present for that key then just initialize it with empty array, push index to the key in each iteration
const appleHolderLine = ['GreenApples', 'RedDelicious','OrangeApples', 'PurpleApples', 'RedDelicious']
var appleMap = {};
for (let i = 0; i < appleHolderLine.length; i++){
if(!appleMap[appleHolderLine[i]]){
appleMap[appleHolderLine[i]] = []
}
appleMap[appleHolderLine[i]].push(i);
}
console.log(appleMap)
You can simply use reduce
const appleHolderLine = ['GreenApples', 'RedDelicious','OrangeApples', 'PurpleApples', 'RedDelicious']
let final = appleHolderLine.reduce((op,inp,i)=>{
op[inp] = op[inp] || []
op[inp].push(i)
return op
},{})
console.log(final)
Line count is simply same as length of array, let lineCount = appleHolderLine.length
I suppose, the shortest answer is the functional one.
const appleHolderLine = ['GreenApples', 'RedDelicious','OrangeApples', 'PurpleApples', 'RedDelicious']
result = appleHolderLine.reduce((a,c,i) => { if(a[c]) a[c].push(i); else a[c]=[i]; return a; }, {})
console.log(result)
But I am not sure that you are expected to deliver a functional solution. Still, you might find it useful. The idea is that the reduce method starts with an empty object and iterates through the array. In each iteration, it checks if the current element c is already a field of the accumulator a. If so adds its index i to the specific field, if not, initializes the field with the current element as name and the index as a single-element array as value.
I am trying to split an array of integers into an array of arrays by duplicate values. The original array is composed of a list of 6 digit integers, some of these integers come in pairs, others come in groups of 3 or 4s. I'd like to get these duplicates pushed to their own arrays and have all of these arrays of duplicates composed into an array of arrays that I can later loop through.
I've looked on in the lodash library for some method or combination of but can't quite find anything that seems to work. I've also tried a few different configurations with nested for loops but also am struggling with that.
const directory = "X/";
let files = fs.readdirSync(directory);
let first6Array = [ ];
for(i=0; i< files.length; i++){
let first6 = files[i].substring(0, 6);
first6Array.push(first6);
};
console.log(first6Array);
example output of first6Array:
[ '141848',
'141848',
'141848',
'142851',
'142851',
'143275',
'143275']
I'd like to end up with something like
let MasterArray = [[141848,141848,141848],[142851,142851],[143275,143275]];
You can use new Set() to filter out the duplicates.
Then you use the unique Array and filter for every value.
const firstArray = [ '141848', '141848', '141848', '142851', '142851', '143275', '143275'];
const numberArray = firstArray.map(Number);
const masterArray = [];
const unique = new Set (numberArray); // Set {141848, 142851, 143275}
unique.forEach(u => {
masterArray.push(numberArray.filter(e => e === u));
});
console.log(masterArray);
Using lodash, you can create a function with flow:
map the items by truncating them and converting to numbers.
groupBy the value (the default).
convert to an array of arrays using values.
const { flow, partialRight: pr, map, truncate, groupBy, values } = _;
const truncate6 = s => truncate(s, { length: 6, omission: '' });
const fn = flow(
pr(map, flow(truncate6, Number)),
groupBy,
values,
);
const firstArray = [ '141848abc', '141848efg', '141848hij', '142851klm', '142851opq', '143275rst', '143275uvw'];
const result = fn(firstArray);
console.log(result);
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>
Use reduce to create an object of arrays, indexed by number, and push to the associated array on each iteration (creating the array at the key first if needed), then get the values of the object:
const directory = "X/";
const files = fs.readdirSync(directory);
const output = Object.values(
files.reduce((a, file) => {
const num = Number(file.slice(0, 6));
if (!a[num]) a[num] = [];
a[num].push(num);
return a;
}, {})
);
It's pretty weird to have an array of identical values, though - you might consider a different data structure like
{
'141848': 3,
'142851': 2
}
to keep track of the number of occurrences of each number:
const output = files.reduce((a, file) => {
const num = file.slice(0, 6);
a[num] = (a[num] || 0) + 1;
return a;
}, {})
To obtain exactly the result you desire, you need a nested find, something like this should works:
const directory = "X/";
let files = fs.readdirSync(directory);
let first6Array = files.reduce((acc, value)=> {
let n = +value.substr(0, 6); // assumes it can't be NaN
let arr = acc.find(nested => nested.find(item => item === n));
if (arr) {
arr.push(n);
} else {
acc.push([n]);
}
return acc;
}, []);
console.log(first6Array);
Notice that an hashmap instead, with the value and the number of occurrence, would be better, also in term of performance, but I don't think it mind since you have really few elements.
Also, it assumes the first six characters are actually numbers, otherwise the conversion would fail and you'll get NaN.
It would be safer adding a check to skip this scenario:
let n = +value.substr(0, 6);
if (isNaN(n)) {
return acc;
}
// etc