Javascript array length through user input - javascript

I have a problem in Javascript I want to make a form which have one input text field and one button when I click on the button window.prompt is called.
It will prompt depend upon my array length but I want array length get through input text field when I write 10 it will prompt 10 times when I write 2 it will prompt 2 times.
How can i write this type of query?
I tried this code but its not working.
words = new Array (4);
function a() {
for ( k = 0 ; k < words.length ; k = k + 1 ) {
words[ k ] = window.prompt( "Enter word # " + k, "" ) ;
}
}

Maybe you forgot to call your function a().
Some remarks about your code:
You don't have to specify an initial array size, e.g. words = [] or words = new Array() is enough.
Also k=k+1 is usually written as k++.
A remark about asking questions:
Use punctuation to make sentences! Your whole question is one sentence.

Hopefully it's just the snippet of code but I hope you are using var somewhere to declare all those variables.
Otherwise this should do the trick, however not sure what you are trying to achieve but this sounds like a bad user experience.
Here is the jsffidle http://jsfiddle.net/R2bCz/1/
function Handler(event) {
var count = event.target.value;
var i = 0;
var words = [];
var word;
for (; i < count; i++) {
word = window.prompt("Enter word # " + i, "");
words.push(word);
}
}
$("#multi").on("change", Handler);

Related

Passing a string through an array looking for regEx

I'm currently making a chatbox in JQuery. I've been using indexOf but I think it might be more efficient to use regExp.
my current code is
function ai(message){
if (username.length<3){
username = message;
send_message("Nice, to meet you " + username + ", how are you doing?");
}
if(message.indexOf("how are you?")>=0) {
send_message("I'm feeling great!");
}
if(message.indexOf("weather")>=0 ){
send_message("In England it is shitty");
}
var n = message.search(/\b(cat|cats|kitten|feline)\b/i);
if (n !== -1) {
send_message("i hate cats");
}
else {
for (i=0; i <= botChat.length; i++) {
var re = new RegExp (botChat[i][0], 'i');
if (re.test(message)) {
var length = botChat[i].length - 1;
var index = Math.ceil( length * Math.random());
var reply = (botChat[i][index]);
send_message(reply);
}
}
}
}
and a typical line from my array is
new Array ("I need (.*)\." , "Why do you need $1?", "Would it really help you to get $1?" , "Are you sure you need $1?"),
i'm trying to demonstrate the ways of creating a chatbot. The first four responses work perfectly
it takes a name, comments on the weather and can search for cats. What it can't do is perform the loop. Has anyone any suggestions?

Regex not matching properly

Ive been working on this regex for days now and I cant get it figured out. It either passes everything I put in there or it kicks everything out and I cannot seem to make it function. Admittedly I am new to doing this complex of stuff with Javascript so It may be that you realy cant do this.
I want to check onkeypress what was entered into the input and then validate it to x, y, or z. Then from there send it on about its way to do other neat stuff.
So the question is what the heck am I not understanding about RegExp?
Here is a FIDDLE for it.
function val() {
var gradeIn = document.querySelectorAll("#letGrade input[type=text]");
var checkGrade = new RegExp(/[xyz]/gi);
for (var i = 0; i < gradeIn.length; i++) {
if (!checkGrade.test(gradeIn.value)) {
alert ("This must be X, Y, or Z");
return false;
} else {
return true;
}
}
};
EDIT/UPDATE:
I was trying to do this on keypress and validate each text input individualy however this was realy kinda squishy in the grand scheme of things and not working out exactly correct. I decided to validate all text inputs onsubmit and have everything go all at once. Updated code is below.
function calcGPA() {
var grades = document.querySelectorAll("#letGrade input[type=text]");
var contacts = document.querySelectorAll("#conHours input[type=text]");
var gVals = [];
var cVals = [];
var failGrade = "The Letter Grade input may only be A, B, C, D or F";
var failHours = "The Contact Hours input may only be 1, 2, 3, 4 or 5";
var checkGrade = /^[ABCDF]/;
var checkhours = /^[12345]/;
for (var i = 0; i < grades.length; i++) {
if (!checkGrade.test(grades[i].value)) {
alert(failGrade);
return false;
}
if (!checkhours.test(contacts[i].value)) {
alert(failHours);
return false;
}
gVals.push(grades[i].value);
cVals.push(contacts[i].value);
}
//Other cool stuff happens here
};
Now to just finish the conversion piece for the letters to numbers and the math piece. Thank you for your help on this!
The problem's not only with your regular expression.
if (!checkGrade.test(gradeIn[i].value)) {
You weren't checking each grade. Now if you want it to only be those characters, you have to extend the regular expression a bit. Also, there's no point calling new RegExp if you're using native syntax.
var checkGrade = /^[xyz]+$/;
That means that you're OK with the fields being like "xxyyz" or "zzy". If it should just be one character, that'd be
var checkGrade = /^[xyz]$/;

Letters to predefined numbers conversion in one window

)
I have searched high and low, but i can´t find what i need. Or i´m to stupid to get it right ;-)
I need a page with several input boxes where i can type some text, and then an output area below each input, that shows the text converted to some predefined numbers.
example:
input: abcde fghi æøå (i need all kinds of characters like .,/: etc.)
output: 064 065 066 067 068 032
So it needs to convert like this:
"a"="064 "
"b"="065 "
"space"="032 "
(and yes, each number in output needs to be separated, or a space added after each number)
I have tried some different cipher guides in both php and javascript, but can´t get it to work. I did do an Excel document that could do some of it, but it had a limited amount of characters it could convert, then it started behaving weird. So i thought maybe PHP was the answer!
Any help is very appreciated
/Rasmus
In the spirit of elclanrs deleted answer, and for posterity:
<script>
// Using standard for loop
function stringToCharcodes(s) {
var result = [];
function pad(n){ return (n<10? '00' : n<100? '0' : 0) + n;}
for (var i=0, iLen=s.length; i<iLen; i++) {
result.push(pad(s.charCodeAt(i)));
}
return result.join(' ');
}
// Using ES5 forEach
function stringToCharcodes2(s) {
var result = [];
function pad(n){ return (n<10? '00' : n<100? '0' : 0) + n;}
s.split('').forEach(function(a){result.push(pad(a.charCodeAt(0)))});
return result.join(' ');
}
</script>
<input onkeyup="document.getElementById('s0').innerHTML = stringToCharcodes(this.value);"><br>
<span id="s0"></span>
Edit
If you want a custom mapping, use an object (I've only included 2 characters, you can add as many as you want):
var mapChars = (function() {
var mapping = {'198':'019', '230':'018'};
return function (s) {
var c, result = [];
for (var i=0, iLen=s.length; i<iLen; i++) {
c = s.charCodeAt(i);
result.push(c in mapping? mapping[c] : c);
}
return result.join(' ');
}
}());
alert(mapChars('Ææ')); //
Using the character code for mapping seems to be a reasonable solution, using the actual character may be subject to different page character encoding.

Javascript for Variations with Repetition (combinatorics) of missing string characters

My question is similar to THIS question that hasn't been answered yet.
How can I make my code (or any javascript code that might be suggested?) find all possible solutions of a known string length with multiple missing characters in variation with repetition?
I'm trying to take a string of known character lengths and find missing characters from that string. For example:
var missing_string = "ov!rf!ow"; //where "!" are the missing characters
I'm hoping to run a script with a specific array such as:
var r = new Array("A","B","C","D","E","F","G","H","I","J","K",
"L","M","N","O","P","Q","R","S","T","U","V",
"W","X","Y","Z",0,1,2,3,4,5,6,7,8,9);
To find all the possible variations with repetition of those missing characters to get a result of:
ovArfAow
ovBrfAow
ovCrfAow
...
ovBrfBow
ovBrfCow
...
etc //ignore the case insensitive, just to emphasize the example
and of course, eventually find ovErfLow within all the variations with repetition.
I've been able to make it work with 1 (single) missing character. However, when I put 2 missing characters with my code it obviously repeats the same array character for both missing characters which is GREAT for repition but I also need to find without repetition as well and might need to have 3-4 missing characters as well which may or may not be repeated. Here's what I have so far:
var r = new Array("A","B","C","D","E","F","G","H","I","J","K",
"L","M","N","O","P","Q","R","S","T","U","V",
"W","X","Y","Z",0,1,2,3,4,5,6,7,8,9);
var missing_string = "he!!ow!r!d";
var bt_lng = missing_string.length;
var bruted="";
for (z=0; z<r.length; z++) {
for(var x=0;x<bt_lng;x++){
for(var y=0;y<r.length;y++){
if(missing_string.charAt(x) == "!"){
bruted += r[z];
break;
}
else if(missing_string.charAt(x) == r[y]){
bruted += r[y];
}
}
}
console.log("br: " + bruted);
bruted="";
}
This works GREAT with just ONE "!":
helloworAd
helloworBd
helloworCd
...
helloworLd
However with 2 or more "!", I get:
heAAowArAd
heBBowBrBd
heCCowCrCd
...
heLLowLrLd
which is good for the repetition part but I also need to test all possible array M characters in each missing character spot.
Maybe the following function in pure javascript is a possible solution for you. It uses Array.prototype.reduce to create the cartesian product c of the given alphabet x, whereby its power n depends on the count of the exclamation marks in your word w.
function combinations(w) {
var x = new Array(
"A","B","C","D","E","F","G","H","I","J","K",
"L","M","N","O","P","Q","R","S","T","U","V",
"W","X","Y","Z",0,1,2,3,4,5,6,7,8,9
),
n = w.match(/\!/g).length,
x_n = new Array(),
r = new Array(),
c = null;
for (var i = n; i > 0; i--) {
x_n.push(x);
}
c = x_n.reduce(function(a, b) {
var c = [];
a.forEach(function(a) {
b.forEach(function(b) {
c.push(a.concat([b]));
});
});
return c;
}, [[]]);
for (var i = 0, j = 0; i < c.length; i++, j = 0) {
r.push(w.replace(/\!/g, function(s, k) {
return c[i][j++];
}));
}
return r;
}
Call it like this console.log(combinations("ov!rf!ow")) in your browser console.

JavaScript filtering an array of <input> values by character count

This should be a quickie, but I'm scratching my head as to why this bit of JavaScript isn't working for me. The goal is to take the value of an input box (string of words separated by spaces), list these words as items in an array, and remove those which are fewer than 3 characters:
var typed = $('input').val();
var query = typed.split(" ");
var i=0;
for (i=0; i<query.length; i++) {
if (query[i].length < 3) {
query.splice(i,1);
}
}
Have this running onkeyup for the input box and it seems to work, but only about 50% of the time (strings of 1 and 2 characters somehow find their way into the array on occasion). Any suggestions would be hugely appreciated.
The problem is that you are iterating while removing the elements. Consider this array:
["he", "l", "lo world"]
Initially your loop starts at index 0 and removes "he" from the array. Now the new array is
["l", "lo world"]
In the next iteration i will be 1, and you will check "lo world"'s length, thus ignoring the "l" string altogether.
Use the filter method in Array to remove the unwanted elements.
var biggerWords = query.filter(function(word) {
return word.length >= 3;
});
Besides the iterating problem, you may also see unexpected entries if you type multiple spaces
try
var query = typed.split(/\s+/);
This way it will split on any number of spaces, instead of each individual one
The problem is that you're slicing the array while counting forward. Think about it...if you take an index point out of the array, thereby shortening it by one, incrementing i and moving on to the next one actually moves one further than you want, completely missing the next index. Increment i--, start at query.length-1, and make the condition that i>=0. For an example of this in action, check it out here:
http://jsfiddle.net/kcwjs/
CSS:
input {
width:300px;
}​
HTML:
<input id="textbox" type="text" />
<div id="message"></div>​
Javascript:
$(document).ready(function() {
$('#textbox').keyup(checkStrings);
});
function checkStrings(e) {
var typed = $('#textbox').val();
if (typed == "") return false;
var query = typed.split(" ");
var querylen = query.length;
var acceptedWords = '';
var badWords = '';
for (var i = querylen-1; i >= 0; i--) {
if (query[i].length < 3) {
badWords += query[i] + " ";
} else {
acceptedWords += query.splice(i,1) + " ";
}
}
$('#message').html("<div>Bad words are: " + badWords + "</div>" +
"<div>Good words are: " + acceptedWords + "</div>");
}
Try this code, it get's rid of any 3 character words, as well as making sure no empty array elements are created.
typed.replace(/(\b)\w{1,3}\b/g,"$1");
var query = typed.split(/\s+/);
hey i think you should use a new array for the result. since you are removing the element in array. the length is changed. here is my solution
var typed = "dacda cdac cd k foorar";
var query = typed.split(" ");
var i=0;
var result = [];
for (i=0; i<query.length; i++) {
if (query[i].length >= 3) {
result.push(query[i]);
}
}

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