As title. I tried the following javascript.
This will console.log() the same random number 20 times, but how do I go about 20 random characters? Are we using callback function?
var letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
var insert = letters.charAt(Math.floor(Math.random() * letters.length));
var str = "0";
for (i = 0; i < 20; i++) {
setTimeout(function() {
var newStr = str.replace(/./, insert);
console.log(newStr)
}, 50 * i)
}
This line:
var insert = letters.charAt( Math.floor(Math.random()*letters.length) );
runs once and once only. It does not re-run the random part every time you ask for the value of insert.
You could rerun it manually every loop:
var letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
var str = "0";
for(i=0; i<20; i++) {
setTimeout(function(){
var insert = letters.charAt( Math.floor(Math.random()*letters.length) );
var newStr = str.replace(/./, insert);
console.log(newStr)
}, 50*i)
}
But keep in mind that you might get the same character more than once, as by definition it is (pseudo) random - and therefore could pick the same character as has been previously picked.
To ensure you get a distinct random character each time you would have to remove a picked character from the list. Easier to do by converting the characters to an array and using splice to remove it once selected:
var letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789".split("");
var str = "0";
for(i=0; i<20; i++) {
setTimeout(function(){
var insert = Math.floor(Math.random()*letters.length);
var newStr = str.replace(/./, letters[insert]);
console.log(newStr)
letters.splice(insert,1);
}, 50*i)
}
Related
I'm beginner in JS. I've tried to understand Caesar Cipher ROT13, but it was too complicated for me. So I've tried to write my own code. Here it is below:
function encrip() {
var alphabet = ["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"];
var str = "Ni Hao";
var string = str.toUpperCase();
for (var i = 0; i < string.length; i++) {
for (var k = 0; k < alphabet.length; k++) {
if(string.charAt(i) == alphabet[k]) {
/* console.log(string.charAt(i) + ' ' + alphabet.indexOf(alphabet[k])); */
}
}
}
}
encrip();
But I am stuck. How to do:
1. Get value from var str and then access to var alphabet , after change each letter from var str value to next 3 from alphabet (var str each element's current position would be changed) For example: Input: Ni Hao ==> output: QL KDR
2. Create universal code, I mean, not only for changing position by 3, but when I give value '5', each element would be changed by next 5 positions from alphabet. So output can be changed when I change its' value
I hope I explained everything clearly. Thanks everyone in advance for help!!
you can use the following function to encrypt english words, the 1st parameter is the string to encrypt and the 2nd for shifting
function encryp(str,pos){
var alpha="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
var strUC=str.toUpperCase();
var enc="";
for(var i=0;i<strUC.length;i++){
if(strUC.charAt(i)!=" "){
enc+=alpha.charAt((alpha.indexOf(strUC.charAt(i))+pos)%26)
}
else{
enc+=" "
}
// in your case pos=3
}
return enc;
}
console.log(encryp("NiHao",3));
You don't need two for loops to do this. Iterate over the input string and find the index of each character in the alphabet array, if found add the shift to it to get the encrypted character.
To handle overflow use the modulus operator to cycle through the array.
Also I assume that you are not going use any special symbols to do the encryption.
function encrip(string, shift) {
var alphabet = ["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"];
string = string.toUpperCase();
let arr = [];
for (var i = 0; i < string.length; i++) {
let char = alphabet.indexOf(string[i]) !== -1 ? alphabet[(alphabet.indexOf(string[i]) %26) + shift] : " ";
arr.push(char);
}
let encryp = arr.join("");
console.log(encryp);
return encryp;
}
encrip("Ni Hao", 3);
First of all, instead of your inner for loop scanning the whole alphabet array, you can use the built-in function indexOf:
alphabet.indexOf('K') // returns 10
Secondly, you'll want to build up your enciphered string in a separate variable. For each letter, get the index of that letter in the alphabet, add your cipher offset parameter to that index and add the resulting letter from the alphabet to your new string. An important step is that when you add to the index of the letter, you want to make sure the resulting index is within range for the alphabet array. You can do that using the % (modulo) operator, which will wrap high values back round to the start of the array. In full:
function encipher(input, offset) {
var alphabet = ["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"];
var str = input.toUpperCase();
var result = '';
for (var i = 0; i < str.length; i++) {
letterIndex = alphabet.indexOf(str.charAt(i));
if (letterIndex === -1) {
result += str[i]; // if the letter isn't found in the alphabet, add it to the result unchanged
continue;
}
cipheredIndex = (letterIndex + offset) % alphabet.length; // wrap index to length of alphabet
result += alphabet[cipheredIndex];
}
console.log(result);
}
encipher('Ni Hao', 5); // output: 'SN MFT'
i have a question that seems basic but i can't seem to figure it out.
Write a program that takes the value of a variable called “input” (declared as any whole number at the top of your program) and outputs a square made of asterisks () as large as the number (input). For example, if the “input” is declared with the value 5, your program would display a square made of 25 asterisks() – ie ; 5 asterisks () high, by 5 asterisks () long.
The code i've come up with so far is below. I don't really understand how to make a string continuously print. If i did star = i then it turns into numbers and will print the numbers. So how do i make it so they connect? I also can't figure out where i should put the new line. console.log(star "\n"); gives me an error. Please help :)
var input = 2;
var star = "*";
var i = 0;
do {
console.log(star);
i++;
} while (i < input);
You can use String.repeat() (ES6 only) along with \r\n to add new line
var input = 5,
star = "*",
str = [],
i = 0;
do {
str.push( Array(input).join(star) ); // use array(length).join
i++;
} while (i < input);
str = str.join("\r\n"); // add breaklines
console.log(str);
console.log Will output a single line to the console containing whatever you pass it as an argument. You are trying to print a line of n asterisks n times.
The first step you should take is constructing the string of asterisks. You can concatenate a string to another with the + operator:
var input = 2;
var star = "*";
var line = "";
for(var i = 0; i < input; i++) {
line = line + star;
}
Once you have constructed line you can then print it n times:
for(var i = 0; i < input; i++) {
console.log(line);
}
Hint: You could create an empty array and then create a loop ending at your wanted number of asterisks after which you will join all the members of the array together. (Writing the code here wouldn't help you much since you mentioned it's an homework).
You could approach this in two ways. If we call your input value n, then we can log either n strings each consisting of n stars, or we can log a single string, containing (n * n) stars, with line breaks after every nth star.
Below is an example of a function that could do this task.
function stars (input) {
var output = ''
for (var i = 0; i < input; i++) {
for (var j = 0; j < input; j++) {
output += '*'
}
output += '\n'
}
return output
}
You can use the repeat-function to print a character multiple times.
var input = 2;
var star = "*";
var i = 0;
while(i++ < input){
console.log(star.repeat(input));
}
This repeats the * character input times in input lines.
I wrote a simple program to analyze a string to find the word with the greatest amount of duplicate letters within it. It essentially takes a given string, breaks it up into an array of separated words, and then breaks up each separate word into alphabetically sorted groups of individual letters (which are then compared as prev and next, 2 at a time, as the containing array is iterated through). Any two adjacent and matching values found adds one tally to the hash-file next to the word in question, and the word with the most tallied pairs of duplicate letters is returned at the end as greatest. No matching pairs found in any word returns -1. This is what it's supposed to do.
Below, I've run into a problem: If I don't use a REGEXP to replace one of my matched characters, then my code gives false positives as it will count triplicates (eg, "EEE"), as two separate pairs, (eg, "EEE" = "EE & EE", instead of being viewed as "EE, E"). However, if I DO use the REGEXP below to prevent triplicate counts, then doing so breaks my loop mid-stride, and skips to the next word. Is there no way to make this way work? If not, would it be better to employ a REGEXP which deletes all chars EXCEPT the duplicate characters in question, and then perhaps I could divide the .length of each word by 2 to get the number of pairs remaining? Any ideas as to how to solve this would greatly help.
var str = "Helloo aplpplpp pie";
//var str = "no repting letrs";
//var str = "ceoderbyte";
function LetterCountI(str) {
var input = str.split(" ");
console.log(input);
console.log("\n")
var hashObject = {};
var word = "";
var count = 0;
for(var i = 0; i<input.length; i++) {
var currentItem = input[i];
var currentWordIntoChars = currentItem.split("").sort();
console.log(currentWordIntoChars);
var counter = 0;
for(var j=1; j<currentWordIntoChars.length; j++) {
console.log(currentWordIntoChars[j-1] + "=currentChar j-1");
console.log(currentWordIntoChars[j] + "=prev j");
console.log("-");
var final = currentItem;
if(currentWordIntoChars[j-1] == currentWordIntoChars[j]) {
counter++;
hashObject[final] = counter;
//currentWordIntoChars = currentWordIntoChars[j-1].replace(/[a-z]/gi, String.fromCharCode(currentItem.charCodeAt(0)+1));
//HERE REPLACE j-1 with random# or something
//to avoid 3 in a row being counted as 2 pair
//OR use regexp to remove all but pairs, and
//then divide .length/2 to get pairs.
console.log(counter + " === # total char pairs");
}
if(count<hashObject[currentItem]) {
word = final;
count = hashObject[currentItem];
}
}
}
console.log(hashObject);
console.log("\n");
for (var o in hashObject) if (o) return word;
return -1;
}
console.log(LetterCountI(str));
An other way to do it, consists to replace duplicate characters in a sorted word:
var str = "Helloo aplpplpp pie";
function LetterCountI(str) {
var input = str.split(" ");
var count = 0;
var result = -1;
for(var i = 0; i<input.length; i++) {
var nb = 0;
var sortedItem = input[i].split("").sort().join("");
sortedItem.replace(/(.)\1/g, function (_) { nb++ });
if (nb > count) {
count = nb;
result = input[i];
}
}
return result;
}
console.log(LetterCountI(str));
Notes: The replace method is only a way to increment nb using a callback function. You can do the same using the match method and counting results.
if two words have the same number of duplicates, the first word will be returned by default. You can easily change this behaviour with the condition of the if statement.
Whenever you find a match within a word, increment j by 1 to skip comparing the next letter.
var str = "Helloo aplpplpp pie";
//var str = "no repting letrs";
//var str = "ceoderbyte";
function LetterCountI(str)
{
var input = str.split(" ");
console.log(input);
console.log("\n")
var hashObject = {};
var word = "";
var count = 0;
for(var i = 0; i<input.length; i++)
{
var currentItem = input[i];
var currentWordIntoChars = currentItem.split("").sort();
console.log(currentWordIntoChars);
var counter = 0;
for(var j=1; j<currentWordIntoChars.length; j++)
{
console.log(currentWordIntoChars[j-1] + "=currentChar j-1");
console.log(currentWordIntoChars[j] + "=prev j");
console.log("-");
var final = currentItem;
if(currentWordIntoChars[j-1] == currentWordIntoChars[j])
{
counter++;
hashObject[final] = counter;
j++; // ADD HERE
console.log(counter + " === # total char pairs");
}
if(count<hashObject[currentItem])
{
word = final;
count = hashObject[currentItem];
}
}
}
console.log(hashObject);
console.log("\n");
for (var o in hashObject) if (o) return word;
return -1;
}
console.log(LetterCountI(str));
I am very, very new at JS with no programming experience and I am struggling with creating a script that counts words in a text box. I have the following code and I can't get anything to populate:
var myTextareaElement = document.getElementById("myWordsToCount");
myTextareaElement.onkeyup = function(){
var wordsCounted = myTextareaElement.value;
var i = 0;
var str = wordsCounted;
var words = str.split('');
for (var i = words.length; i++) {if (words[i].length > 0; i++) { words[i] };
}
And for the Span Id in my HTML, I put the following:
<span id="wordsCounted"></span>
Any direction I where I am royally messing up would be great. I have tried it in JS fiddle and can't get it to populate.
The split method needs a proper character, you can use an space " " or a regex to indicate any whitespace character: "My name is XXX".split(/\s+/) will show ["My", "name", "is", "XXX"].
If you just want the number of words you can do "My name is XXX".split(/\s+/).length, which will return 4.
Try this, this may do what you want. Instead of doing a for loop, just count how many words are there and display the length of the array.
var myTextareaElement = document.getElementById("myWordsToCount");
myTextareaElement.onkeyup = function(){
var wordsCounted = myTextareaElement.value;
var i = 0;
var str = wordsCounted;
var words = str.split('');
if (words.length > 0){
document.getElementById('wordsCounted').innerHTML = words.length;
}
}
I want to generate a string of random letters say 10 letters from a-z one after the other i.e. the next letter should be displayed after the previous letter after a certain delay, later, I want to calculate the number of times each letter has been generated, unlike what I have done previously, i.e. I have taken a predefined array of letters and generated them accordingly.
Shorter way to generate such a string using String.fromCharCode:
for (var i = 0, letter; i < 10; i++) {
setTimeout(function() {
letter = String.fromCharCode(97 + Math.floor(Math.random() * 26));
out.appendChild(document.createTextNode(letter)); // append somewhere
}, 2000 * i);
}
And complete demo covering all the problems in this question: http://jsfiddle.net/p8Pjq/
Use the setInterval method to run code at an interval. Set up an array for counting each character from the start, then you can count them when you create them instead of afterwards:
var text = '';
var chars = 'abcdefghijklmnopqrstuvwxyz';
var cnt = new Array(chars.length);
for (var i = 0; i < cnt.length; i++) cnt[i] = 0;
var handle = window.setInterval(function(){
var ch = Math.floor(Math.random() * chars.length);
cnt[ch]++;
text += chars.charAt(ch);
$('#display').text(text);
if (text.length == 20) {
window.clearInterval(handle);
// now all characrers are created and counted
}
}, 2000);
Demo: http://jsfiddle.net/R8rDH/
I am stealing this answer, but look here: Generate random string/characters in JavaScript
function makeid()
{
var text = "";
var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
for( var i=0; i < 5; i++ )
text += possible.charAt(Math.floor(Math.random() * possible.length));
return text;
}