Matching anagrams and pushing to an array - javascript

I have a given word, that I want to match against a given list of words, mainList, and establish which words of that given list are anagrams of the given word, and add them to another list, subList.
I feel like my method to do this is fine, but it returns an unexpected result.
For example...
var word = 'master';
var mainList = ['stream', 'pidgeon', 'maters'];
var subList = [];
Then I take the word, split to an array of letters, alphabetise, and join back into a string. With this string I should be able match against any possible anagrams (which I will covert in the same way).
var mainSorted = [];
for (i = 0; i < word.length; i++) {
mainSorted = word.split('').sort().join();
}
This is where it goes wrong. I loop through the mainList array trying to establish if a given item, when converted, matches the original. If so, I want to push the word to the subList array.
for (var i = 0; i < mainList.length; i++) {
var subSorted = mainList[i].split('').sort().join;
if (mainSorted === subSorted) {
subList.push(mainList[i])
}
}
return subList;
...and the value I expect to see for subList is: ['stream', 'maters']
Yet I am returned an empty array instead.
I've gone through this so many times and I cannot see what's going wrong, would really appreciate some help!
Also, I'm aware there's probably more eloquent methods to do this (and I welcome any suggestions) but primarily I want to see where this is going wrong.
Thanks in advance.

You forgot () at the end of join
var subSorted = mainList[i].split('').sort().join;
should be
var subSorted = mainList[i].split('').sort().join();
One non-issue is
for (i = 0; i < word.length; i++) {
mainSorted = word.split('').sort().join();
}
doesnt need to be in a loop
mainSorted = word.split('').sort().join();
alone suffices
as a bonus, here's a tidier way of doing what you are doing
var word = 'master';
var mainList = ['stream', 'pidgeon', 'maters'];
var mainSorted = word.split('').sort().join();
return mainList.filter(function(sub) {
return sub.split('').sort().join() == mainSorted;
});

Related

Google scripts. TypeError: Cannot call method "replace" of undefined

First post please go easy on me.
I have an array that looks something like this [BTC-LTC, BTC-DOGE, BTC-VTC] I am trying to change all the "-" with "_". But am having trouble with using the .replace() method. Here is my code.
var array = [BTC-LTC, BTC-DOGE, BTC-VTC];
var fixedArray = [];
for(var i=0; i <= array.length; i++){
var str = JSON.stringify(array[i]);
var res = str.replace("-","_");
fixedArray.push(res);
};
I tried without using the JSON.stringify but that didn't work either. I have also tried to first create var str = String(); this also did not work. Is it possible that the method .replace() is not available in google scripts?
In your example var array = [BTC-LTC, BTC-DOGE, BTC-VTC];
should be
var array = ["BTC-LTC", "BTC-DOGE", "BTC-VTC"];
However I gather from the comments that this is just a typo in your initial example.
var str = JSON.stringify(array[i]); is redundant. You can just do var str = array[i]; Since the value in the array is already a string, there's no need to turn it into one again - the "stringify" method expects to be given an object or array to work on.
However the main problem is that your for loop goes on one too many iterations. Arrays are zero-based, so you need to stop looping when the index is 1 less than the length of the array, not equal to it. e.g. if array.length is 10 then there are 10 indices, but they start at 0, so the indices are 0,1,2,3,4,5,6,7,8,9. If your loop goes on to equal to array.length, then on the last loop array[10] will be out of bounds, and it's only this last iteration which is giving you the undefined error.
var array = ["BTC-LTC", "BTC-DOGE", "BTC-VTC"];
var fixedArray = [];
for (var i = 0; i < array.length; i++) {
var str = array[i];
var res = str.replace("-","_");
fixedArray.push(res);
}
If I understood correctly, you're trying to edit strings, not variables, so you need quotes in your array, and a g in your replace in case you have multiple things to replace :
var array = ['BTC-LTC', 'BTC-DOGE', 'BTC-VTC'];
var fixedArray = [];
for(var i=0; i <= array.length; i++){
fixedArray.push(array[i].replace(/-/g, '_'));
};
code is working fine if we change as below:
var array = ['BTC-LTC', 'BTC-DOGE', 'BTC-VTC'];

How to use a regexp to replace each item in an array using javascript

I'm a beginner with javascript, and after searching I am still running into an error with this part of my code.
I have an array:
var choices = [ '$5/hr', '$6/hr', '$7/hr', '$10/hr' ];
And I want to use a regular expression to return the array as integers so I can use it for further calculations. I know that replace only works on strings and not an array so I have tried the following:
// Strip other characters and return only integers.
for (var i = 0; i < choices.length; i++) {
choices[i] = choices[i].replace(/[^0-9.]/g, '');
}
EDIT: Apparently the issue is somewhere else in my code. Maybe this needs to be wrapped in another function?
Here is the function that this resides in. This function receives an array as a value and will calculate an average using the array received and the choices array which I cannot convert to integers.
// Choice values
var ul = document.getElementById('Results');
var choices = [];
// Get li element choices
for (var i = 0; i < ul.childNodes.length; i++) {
if (ul.childNodes[i].nodeName == "LI") {
choices.push(ul.childNodes[i]);
}
}
// Strip the last element in array since it is the result container.
choices.splice(-1,1);
// Strip other characters and return only integers.
for (var i = 0; i < choices.length; i++) {
choices[i] = choices[i].replace(/[^0-9.]/g, '');
}
Thanks!
The issue is that you are pushing the nodes in your array, not their text content. Try this instead:
choices.push(ul.childNodes[i].textContent)
or:
choices.push(ul.childNodes[i].childNodes[0].nodeValue)

How to split a URL string with parameters into an array using JavaScript

I'm trying to break up a string like this one:
fname=bill&mname=&lname=jones&addr1=This%20House&...
I want to end up with an array indexed like this
myarray[0][0] = fname
myarray[0][1] = bill
myarray[1][0] = mname
myarray[1][1] =
myarray[2][0] = lname
myarray[2][1] = jones
myarray[3][0] = addr
myarray[3][1] = This House
The url is quite a bit longer than the example. This is what I've tried:
var
fArray = [],
nv = [],
myarray = [];
fArray = fields.split('&');
// split it into fArray[i]['name']="value"
for (i=0; i < fArray.length; i++) {
nv = fArray[i].split('=');
myarray.push(nv[0],nv[1]);
nv.length = 0;
}
The final product is intended to be in 'myarray' and it is, except that I'm getting a one dimensional array instead of a 2 dimensional one.
The next process is intended to search for (for example) 'lname' and returning the index of it, so that if it returned '3' I can then access the actual last name with myarray[3][1].
Does this make sense or am I over complicating things?
Your line myarray.push(nv[0],nv[1]); pushes two elements to the array myarray, not a single cell with two elements as you expect (ref: array.push). What you want is myarray.push( [nv[0],nv[1]] ) (note the brackets), or myarray.push(nv.slice(0, 2)) (ref: array.slice).
To simplify your code, may I suggest using Array.map:
var q = "foo=bar&baz=quux&lorem=ipsum";
// PS. If you're parsing from a-tag nodes, they have a property
// node.search which contains the query string, but note that
// it has a leading ? so you want node.search.substr(1)
var vars = q.split("&").map(function (kv) {
return kv.split("=", 2);
});
For searching, I would suggest using array.filter:
var srchkey = "foo";
var matches = vars.filter(function (v) { return v[0] === srchkey; });
NB. array.filter will always return an array. If you always want just a single value, you could use array.some or a bespoke searching algorithm.
for (var i = 0; i < fArray.length; i++) {
nv = fArray[i].split('=');
myarray.push([nv[0],nv[1]]);
}
nv.length = 0; is not required, since you're setting nv in each iteration of the for loop.
Also, use var i in the for-loop, otherwise, you're using / assigning a global variable i, that's asking for interference.

JavaScript - Search for first character in an Array

I'm trying to find the first character in an Array in JavaScript.
I have this a random function (not the best, but I am going to improve it):
function random() {
var Rand = Math.floor(Math.random()*myArray.length);
document.getElementById('tr').innerHTML = myArray[Rand];
}
And here's my Array list.
myArray = ["where", "to", "get", "under", "over", "why"];
If the user only wants arrays with W's, only words with a W in the first letter is shown. (Like "where" or "why")
I do not have a lot of experience with JavaScript from before and I have been sitting with this problem for ages.
There's indexOf() method of an array/string which can provide you with a position of a letter. First letter has a position of 0(zero), so
function filter(letter) {
var results = [];
var len = myArray.length;
for (var i = 0; i < len; i++) {
if (myArray[i].indexOf(letter) == 0) results.push(myArray[i]);
}
return results;
}
Here is a jsFiddle for it. Before running open the console(Chrome: ctrl+shift+i, or console in FireBug) to see resulting arrays.
You can filter the array to contain only specific values, such as the ones starting with 'w'
var words = ["where", "to", "get", "under", "over", "why"];
var wordsWithW = words.filter(function(word) {
return word[0] == 'w';
});
var randomWordWithW = wordsWithW[Math.floor(Math.random() * wordsWithW.length];
... // operate on the filtered array afterwards
If you plan to support the aged browsers you might want to consider using underscore.js or Prototype
When using underscore you could simply write this:
var randomWordWithW = _.chain(words).filter(function(word) {
return word[0] == 'w';
}).shuffle().first().value()

fastest way to loop through an array

I want to return an array when one of the elements matches an item within an array.
Is the below code the fastest way to loop through an array when a value matches in a javascript array of arrays?
Note : Welcome any suggestions to modify the variable relatedVideosArray to make it a different data structure for better performance.
var relatedVideosArray = [
["1047694110001"],
["1047694111001", "1019385098001","1020367665001","1020367662001", "1019385097001", "1020367667001"],
["1040885813001"],
["1019385094001", "1019385096001"],
["952541791001", "952544511001", "952544512001", "952544508001", "952541790001","952580933001", "952580934001", "1051906367001"]
]
function getRelatedVideos(videoClicked){
var tempStoreArray = [];
var getCurrentId = videoClicked;
var relVideoslen = relatedVideosArray.length;
for(var i in relatedVideosArray) {
tempStoreArray = relatedVideosArray[i];
for(var j in tempStoreArray){
if(tempStoreArray[j] == getCurrentId){
return relatedVideosArray[i];
}
}
}
}
Update: I initially thought of making a key of video ids and values as all the related ids, but I want to display the key as well as all the related ids if any of the ids within the value array are clicked. Hope this helps to explain the constraint I have.
Modern day browsers support Array indexOf.
For the people saying the array indexOf is slower, basic tests on speed.
var values = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20];
console.time("for");
for(var i=0;i<1000;i++){
for(var j=0;j<=values.length;j++){
if(values[j]===20) break;
}
}
console.timeEnd("for");
console.time("reverse for");
for(i=0;i<1000;i++){
for(var j=values.length-1;j>=0;j--){
if(values[j]===1) break;
}
}
console.timeEnd("reverse for");
console.time("while");
for(i=0;i<1000;i++){
var j=0;
while (j<values.length){
if(values[j]===20) break;
j++;
}
}
console.timeEnd("while");
console.time("reverse while");
for(i=0;i<1000;i++){
var j=values.length-1;
while (j>=0){
if(values[j]===1) break;
j--;
}
}
console.timeEnd("reverse while");
console.time("indexOf");
for(var i=0;i<1000;i++){
var x = values.indexOf(20);
}
console.timeEnd("indexOf");
console.time("toString reg exp");
for(var i=0;i<1000;i++){
var x = (/(,|^)20(,|$)/).test(values.toString);
}
console.timeEnd("toString reg exp");
Two possible solutions:
var relatedVideosArray = [
["1047694110001"],
["1047694111001", "1019385098001","1020367665001","1020367662001", "1019385097001", "1020367667001"],
["1040885813001"],
["1019385094001", "1019385096001"],
["952541791001", "952544511001", "952544512001", "952544508001", "952541790001","952580933001", "952580934001", "1051906367001"]
]
//var getCurrentId = "1019385098001";
var getCurrentId = "1040885813001";
console.time("indexOf");
var tempStoreArray = [];
for(var i = relatedVideosArray.length-1; i>=0; i--){
var subArr = relatedVideosArray[i];
if(subArr.indexOf(getCurrentId)!==-1){
tempStoreArray.push(subArr);
}
}
console.timeEnd("indexOf");
console.log(tempStoreArray);
console.time("toString reg exp");
var tempStoreArray = [];
var re = new RegExp("(,|^)" + getCurrentId + "(,|$)");
for(var i = relatedVideosArray.length-1; i>=0; i--){
var subArr = relatedVideosArray[i];
if(re.test(subArr.toString())){
tempStoreArray.push(subArr);
}
}
console.timeEnd("toString reg exp");
console.log(tempStoreArray);
I believe so if you keep your current structure. Unless you have a way of 'flattening' the array first, so that rather than being nested, there is simply one array with all the values. If this is out of your control or impractical, then you have no other choice than to iterate over every element and its elements.
Otherwise, would you be able to add the values to a map? The current video id would be the key, and the value would be the list of related videos.
If you have control over the data structure then I highly recommend changing it to something more amenable to the type of searches you are performing. First thing that comes to mind is an array of associative arrays. Each of your video arrays would be keyed with the video id ( set the value to anything you want ). That would make your search O(n), where n = the total number of video lists you have.
I'll post some code for this when I get in front of the computer.

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