Suppose I have the string : "((a,(b,c)),(d,(e,(f,g))))"
How would I go about extracting each pair separately such as splitting the first pair and extracting (a,(b,c)) and (d,(e,(f,g))).
I am kind of lost as to how I should approach this. Since the pairs can vary as the example I can't exactly look for a set pattern.
I believe an approach to this would be identifying where the "," is in the outer most parentheses. such as finding it in ( (set of pairs 1) , (set of pairs 2)).
so I can then be able to take everything left of it and right of it. But I do not know how to do this. Using str.Indexof() will take the first occurrence of "," which is not the one I am interested in.
I would loop through the string's characters keeping track of how nested the parentheses are, to find the first comma that isn't nested, and then (as you said) take the parts to the left and right of that:
function getPairs(input) {
// remove outer parentheses, if present
if (input[0] === "(")
input = input.slice(1,-1);
// find first comma that isn't inside parentheses
var parenNestLevel = 0;
for (var i = 0; i < input.length; i++) {
if (parenNestLevel === 0 && input[i] === ",")
return [input.slice(0, i), input.slice(i+1)];
else if (input[i] === "(")
parenNestLevel++;
else if (input[i] === ")")
parenNestLevel--;
}
// note: returns undefined if the input couldn't be parsed
}
var input = "((a,(b,c)),(d,(e,(f,g))))";
var pairs = getPairs(input);
console.log(pairs);
console.log(getPairs(pairs[0]));
For your input, that would return the array ["(a,(b,c))", "(d,(e,(f,g)))"], and you could then run getPairs() on the parts of the returned array, or make it recursive, or whatever - you don't really make it clear what the final output should be from your sample "((a,(b,c)),(d,(e,(f,g))))" input.
Here is a simpler solution. We first remove the first and last parenthesis, then split the resulting string with '),(', then iterate over the result and prepend/append the missing parenthesis to individual elements depending on their position:
var a = "((a,(b,c)),(d,(e,(f,g))))";
var b = a.substring(1,a.length-1); //remove first and last parenthesis
var c = b.split('),('); //get pairs
for(var i=0;i<c.length;i++){
if(i%2===0){
c[i] = c[i]+')';
}else{
c[i] = '('+c[i];
}
}
console.log(c); // ["(a,(b,c))", "(d,(e,(f,g)))"]
Related
Good evening, I attempting to detect duplicate characters in a string. More specifically, I am trying to find up to two different duplicates within an Array. If there is one duplicate, add a sub-string, and if there is another duplicate, add a different sub-string. Is there any way to do this?
Here is some example code I have so far:
var CodeFieldArray = ["Z80.0", "Z80.1", "Z80.0", "Z70.4"];
/* We have an array here used to create the final string at the end of the
code. It is a dummy array with similar variables in my actual code. For
reference sake, there may be only one object in the array, or 7 total,
depending on the user's input, which is where the duplicate detection should
come in, in case the user enters in multiples of the same code. */
var i, Index;
for (i = 0, L = 0; i < CodeFieldArray.length; i++) {
Index = CodeFieldArray[i].indexOf(CodeFieldArray[i]);
if(Index > -1) L += 1;
Extra0 = CodeFieldArray.indexOf("Z80.8");
Extra1 = CodeFieldArray.indexOf("Z80.9");
if(L >= 2 && Extra0 == -1) CodeFieldArray.push("Z80.8");
Extra0 = CodeFieldArray.indexOf("Z80.8");
if(L >= 4 && Extra0 != -1 && Extra1 == -1) CodeFieldArray.push("Z80.9");
console.println(Extra0);
}
/*^ we attempted to create arguments where if there are duplicates
'detected', it will push, "Z80.8" or, "Z80.9" to the end of the Array. They
get added, but only when there are enough objects in the Array... it is not
actually detecting for duplicates within the Array itself^*/
function UniqueCode(value, index, self) {
return self.indexOf(value) === index;
}
CodeFieldArray = CodeFieldArray.filter(UniqueCode);
FamilyCodes.value = CodeFieldArray.join(", ");
/* this is where we turn the Array into a string, separated by commas. The expected output would be "Z80.0, Z80.1, Z70.4, Z80.8"*/
I have it to where it will add "Z80.8" or "z80.9" if they are not present, but they are being added, only if there are enough objects in the Array. My for-loop isn't detecting specifically the duplicates themselves. If there was a way to detect specifically the duplicates, and create an argument based off of that, then we would be doing grand. The expected output would be "Z80.0, Z80.1, Z70.4, Z80.8"
You can use Set and forEach and includes
var CodeFieldArray = ["Z80.0", "Z80.1", "Z80.0", "Z70.4"];
let unique = [...new Set(CodeFieldArray)];
let match = ['Z80.8','Z80.9'];
let numOfDup = CodeFieldArray.length - unique.length;
if(numOfDup){
match.forEach(e=>{
if(!unique.includes(e) && numOfDup){
unique.push(e);
numOfDup--;
}
})
}
console.log(unique.join(','))
So the idea is
Use Set to get unique values.
Now see the difference between length of original array and Set to get number of duplicates.
Now will loop through match array and each time we push item from match array into unique we reduce numOfDup by so ( to handle case where we have only one duplicate or no duplicate ).
In the end join by ,
You could do something like this:
var uniqueArray = function(arrArg) {
return arrArg.filter(function(elem, pos,arr) {
return arr.indexOf(elem) == pos;
});
};
uniqueArray ( CodeFieldArray )
I am looping through various cells and want to add their string content do an array, if the content is not already in the array. It works perfectly fine when I do it manually like so, trying to add 'eJobs' to the array (see below "var item = 'eJobs') which already containts 'eJobs':
var divisionarray = ['eJobs']
for (var i = 0; i < cells_users.length-1; ++i) {
var row_users = cells_users[i];
if (row_users[0] == user_ldap) {
var podarray = row_users[1].split(', ')
for (j = 0; j < podarray.length; j++) {
for (var k = 0; k < cells_edit.length; ++k) {
var row_edit = cells_edit[k]
if (podarray[j] === row_edit[0]) {
var item = 'eJobs'
if (!(divisionarray.indexOf(item) >= 0)) {
divisionarray.push(item)
}
}
}
}
Logger.log(divisionarray)
As expected, the log file shows [17-10-08 19:11:04:111 BST] [eJobs], illustrating that the code works and 'eJobs' has not been added to the array as it is already in the array.
Now, when I change var item='eJobs' to values of a range
var item = sheet_pods_edit.getRange(startRow+k, startColumn+1).getValue();
the code does not work anylonger, as the log file shows:
[17-10-08 19:14:03:770 BST] [eJobs, eJobs, BestJobs, Vivre Deco, ...
Note I have a range of thousands of cells, so I get alot of duplicates added. What am I missing? Note the cells of the defined range are indeed just strings with a single word (e.g. 'eJobs').
The code is working and the log file is indicating what the problem is..
[eJobs, eJobs, BestJobs, Vivre Deco,
In the second eJobs there is a white space before eJobs, so the first value and the second value don't match.
Without seeing your data and going by the 'just strings with a single word' I would say that using a .replace(" ", "") on the text string should work, this will find the first " " in the string and remove it. I.e. " eJobs" would become "eJobs".
2.
Is this line of code just for testing? You should never use a method like this in a script. It will be extremely inefficient
var item = sheet_pods_edit.getRange(startRow+k, startColumn+1).getValue();
Instead get the full range using .getValues()and iterate over it then.
3.
Is there a reason you are using === in if (podarray[j] === row_edit[0]) unless you need to check for type always use ==
I have seen several answers on Stackoverflow but none have helped me. I have a huge array of nearly 100,000 words, of which I am trying to remove all words that contain a number. I am using the following to do that:
for(var i = 0; i < words.length; i++){
if (hasNumbers(words[i]) {
words.splice(i, 1);
}
function hasNumbers(t)
{ return /\d/.test(t); }
It seems to work, but not all the time because I am still getting words that contain numbers. What can I change to make this remove all words that contain any number at all?
(I am using p5.js with my js)
That is because when you delete a word at index i, the next word will have index i, yet you still increase i, thereby skipping a word which you never inspect.
To solve this you can go backwards through your array:
for(var i = words.length - 1; i >= 0; i--){
// etc.
Here is a shorter way to remove words with digits:
words = words.filter(a => !hasNumbers(a));
Finally, you really should call your second function hasDigits instead of hasNumbers. The words "digit" and "number" have a slightly different meaning.
Here is a snippet, using ES6 syntax, that defines the opposite function hasNoDigits and applies it to some sample data:
let words = ['abcd', 'ab0d', '4444', '-)#', '&9ยต*'];
let hasNoDigits = s => /^\D*$/.test(s);
console.log(words.filter(hasNoDigits));
words = words.filter(a => !hasNumbers(a));
I had started writing this and then trincot answered. His answer is correct, though with the popular and widespread usage of ES5 array functions, I feel like you could simplify this down quite a bit.
window.addEventListener('load', function() {
var data = [
'w3.org',
'google.com',
'00011118.com'
]; //This is supposed to be your data, I didn't have it so I made it up.
var no_nums = data.filter(function(item) {
//Tests each string against the regex, inverts the value (false becomes true, true becomes false)
return !/\d/.test(item);
});
var results = document.getElementById('results');
no_nums.forEach(function(item) {
results.innerHTML += item + '<br />';
//Loops through each of our new array to add the item so we can see it.
});
});
<div id="results">
</div>
This question already has answers here:
How could I manipulate this array in Javascript for this kind of error checking?
(4 answers)
Closed 8 years ago.
How can I make sure that two commas are not entered in an Array .. this is for a web application that generates an array from user input and it's a text field .. I cant change it to anything else.
example .. var names=["Kim",,"Andrew","Ashley"];
in this array , we have two consecutive commas, instead of one .. how can i make sure that if the user enters any character that wouldn't be good , I just take it out .. like comma , dot, etc .. for the example of the extra comma , how would this be achieved considering that I have no other option but deal with a text field generating an array like this
Run the array through a function (see below) to remove the invalid values in your array. In your case, the values are undefined for the second element in ["Kim",,"Andrew","Ashley"].
var stripEmpty = function (ary) {
var result = [];
for (var i = 0; i < ary.length; i++) {
if (ary[i] !== undefined) {
result.push(ary[i]);
}
}
return result;
};
Then you can do this:
var names = ["Kim",,"Andrew","Ashley"];
var strippedNames = stripEmpty(names); // ["Kim","Andrew","Ashley"]
See working fiddle: http://jsfiddle.net/amyamy86/LymAZ/
Two consecutive commas (or a leading comma) is an elision, it increments the index of the next member. The elided member doesn't exist as a property of the array. To find such members, you can use the in operator:
var a = [,0,1,, , ,2,3,, ,];
var i = a.length;
while (i--) {
if (!(i in a)) { // returns true if a has no index i
a.splice(i, 1);
}
}
alert(a); // 0,1,2,3
This also deals with extra spaces in the array literal.
This isn't a bug per say, it's just that you are having null entries from your form being added to your array. try this:
//assume your array has been filled up
var mod_names = names.join("#"); // you can use any delimeter apart from '#'
if(mode_names.indexOf(" ") > -1){
mode_names.replace(/\s+/gi, "");
}
mode_names.replace(/#/gi, " ");
mod_names = mod_names.split(); // the default is a space char
names = mode_names;
Situation
I'm currently writing a javascript widget that displays a random quote into a html element. the quotes are stored in a javascript array as well as how many times they've been displayed into the html element. A quote to be displayed cannot be the same quote as was previously displayed. Furthermore the chance for a quote to be selected is based on it's previous occurences in the html element. ( less occurrences should result in a higher chance compared to the other quotes to be selected for display.
Current solution
I've currently made it work ( with my severely lacking javascript knowledge ) by using a lot of looping through various arrays. while this currently works ( !! ) I find this solution rather expensive for what I want to achieve.
What I'm looking for
Alternative methods of removing an array element from an array, currently looping through the entire array to find the element I want removed and copy all other elements into a new array
Alternative method of calculating and selecting a element from an array based on it's occurence
Anything else you notice I should / could do different while still enforcing the stated business rules under Situation
The Code
var quoteElement = $("div#Quotes > q"),
quotes = [[" AAAAAAAAAAAA ", 1],
[" BBBBBBBBBBBB ", 1],
[" CCCCCCCCCCCC ", 1],
[" DDDDDDDDDDDD ", 1]],
fadeTimer = 600,
displayNewQuote = function () {
var currentQuote = quoteElement.text();
var eligibleQuotes = new Array();
var exclusionFound = false;
for (var i = 0; i < quotes.length; i++) {
var iteratedQuote = quotes[i];
if (exclusionFound === false) {
if (currentQuote == iteratedQuote[0].toString())
exclusionFound = true;
else
eligibleQuotes.push(iteratedQuote);
} else
eligibleQuotes.push(iteratedQuote);
}
eligibleQuotes.sort( function (current, next) {
return current[1] - next[1];
} );
var calculatePoint = eligibleQuotes[0][1];
var occurenceRelation = new Array();
var relationSum = 0;
for (var i = 0; i < eligibleQuotes.length; i++) {
if (i == 0)
occurenceRelation[i] = 1 / ((calculatePoint / calculatePoint) + (calculatePoint / eligibleQuotes[i+1][1]));
else
occurenceRelation[i] = occurenceRelation[0] * (calculatePoint / eligibleQuotes[i][1]);
relationSum = relationSum + (occurenceRelation[i] * 100);
}
var generatedNumber = Math.floor(relationSum * Math.random());
var newQuote;
for (var i = 0; i < occurenceRelation.length; i++) {
if (occurenceRelation[i] <= generatedNumber) {
newQuote = eligibleQuotes[i][0].toString();
i = occurenceRelation.length;
}
}
for (var i = 0; i < quotes.length; i++) {
var iteratedQuote = quotes[i][0].toString();
if (iteratedQuote == newQuote) {
quotes[i][1]++;
i = quotes.length;
}
}
quoteElement.stop(true, true)
.fadeOut(fadeTimer);
setTimeout( function () {
quoteElement.html(newQuote)
.fadeIn(fadeTimer);
}, fadeTimer);
}
if (quotes.length > 1)
setInterval(displayNewQuote, 10000);
Alternatives considered
Always chose the array element with the lowest occurence.
Decided against this as this would / could possibly reveal a too obvious pattern in the animation
combine several for loops to reduce the workload
Decided against this as this would make the code to esoteric, I'd probably wouldn't understand the code anymore next week
jsFiddle reference
http://jsfiddle.net/P5rk3/
Update
Rewrote my function with the techniques mentioned, while I fear that these techniques still loop through the entire array to find it's requirements, at least my code looks cleaner : )
References used after reading the answers here:
http://www.tutorialspoint.com/javascript/array_map.htm
http://www.tutorialspoint.com/javascript/array_filter.htm
http://api.jquery.com/jQuery.each/
I suggest array functions that are mostly supported (and easily added if not):
[].splice(index, howManyToDelete); // you can alternatively add extra parameters to slot into the place of deletion
[].indexOf(elementToSearchFor);
[].filter(function(){});
Other useful functions include forEach and map.
I agree that combining all the work into one giant loop is ugly (and not always possible), and you gain little by doing it, so readability is definitely the winner. Although you shouldn't need too many loops with these array functions.
The answer that you want:
Create an integer array that stores the number of uses of every quote. Also, a global variable Tot with the total number of quotes already used (i.e., the sum of that integer array). Find also Mean, as Tot / number of quotes.
Chose a random number between 0 and Tot - 1.
For each quote, add Mean * 2 - the number of uses(*1). When you get that that value has exceeded the random number generated, select that quote.
In case that quote is the one currently displayed, either select the next or the previous quote or just repeat the process.
The real answer:
Use a random quote, at the very maximum repeat if the quote is duplicated. The data usages are going to be lost when the user reloads/leaves the page. And, no matter how cleverly have you chosen them, most users do not care.
(*1) Check for limits, i.e. that the first or last quota will be eligible with this formula.
Alternative methods of removing an array element from an array
With ES5's Array.filter() method:
Array.prototype.without = function(v) {
return this.filter(function(x) {
return v !== x;
});
};
given an array a, a.without(v) will return a copy of a without the element v in it.
less occurrences should result in a higher chance compared to the other quotes to be selected for display
You shouldn't mess with chance - as my mathematician other-half says, "chance doesn't have a memory".
What you're suggesting is akin to the idea that numbers in the lottery that haven't come up yet must be "overdue" and therefore more likely to appear. It simply isn't true.
You can write functions that explicitly define what you're trying to do with the loop.
Your first loop is a filter.
Your second loop is a map + some side effect.
I don't know about the other loops, they're weird :P
A filter is something like:
function filter(array, condition) {
var i = 0, new_array = [];
for (; i < array.length; i += 1) {
if (condition(array[i], i)) {
new_array.push(array[i]);
}
}
return new_array;
}
var numbers = [1,2,3,4,5,6,7,8,9];
var even_numbers = filter(numbers, function (number, index) {
return number % 2 === 0;
});
alert(even_numbers); // [2,4,6,8]
You can't avoid the loop, but you can add more semantics to the code by making a function that explains what you're doing.
If, for some reason, you are not comfortable with splice or filter methods, there is a nice (outdated, but still working) method by John Resig: http://ejohn.org/blog/javascript-array-remove/