JS/jQuery: how many character occurance in textarea - javascript

Assuming:
str value = 'This is some text';
I want to count how many 't' occurrences, how to do that?

It is much easier with regex
var regex = new RegExp("t", "gi")
var count = "This is some text".match(regex).length;
Will give you counts of t in the given string(ignore case).
You can test it here.
Further reference
RegExp 1
RegExp 2
String
String.match()

var sValue = 'This is some text';
var tCount = sValue.split("t").length - 1;
alert("t appears " + tCount + " times");
If you want to count occurrences of all letters, you better use one loop as shown in the other answers.

An easy solution is to loop
var count = 0;
for(var i = 0; i < str.length; i ++) {
if(str.charAt(i) === 't')
++count;
}
You might also want to use str.toLowerCase(); if you don't want to be case sensitive.

I think you all make it more complicated than it needs to be. Use regex. This is also case insensitive. If you want case sensitive, remove the i after g.
var str = "This is some text";
var pattern = /t/gi;
alert(str.match(pattern).length);
Make it shorter.
var str = "This is some text";
alert(str.match(/t/gi).length);

Several ways to do this...
function countChar(str, searchChar) {
var num=0;
for (var i=0; i<str.length; ++i) {
if (str[i] == searchChar)
++num;
}
return num;
}
use like:
numt = countChar('This is some text', 't');

May be can help you here
.replace().length
with regards
Wazzy

<button onclick="alert(countCharacter('abcdea', 'a'));"> Test! </button>
<script type="text/javascript">
function countCharacter(sample, characterToFind) {
var result = 0;
for(i = 0;i<sample.length;i++) {
if(sample[i] === characterToFind) {
result++;
}
}
return result;
}
</script>

Related

How to replace all same charter/string in text with different outcomes?

For example let's say I want to attach the index number of each 's' in a string to the 's's.
var str = "This is a simple string to test regex.";
var rm = str.match(/s/g);
for (let i = 0;i < rm.length ;i++) {
str = str.replace(rm[i],rm[i]+i);
}
console.log(str);
Output: This43210 is a simple string to test regex.
Expected output: This0 is1 a s2imple s3tring to tes4t regex.
I'd suggest, using replace():
let i = 0,
str = "This is a simple string to test regex.",
// result holds the resulting string after modification
// by String.prototype.replace(); here we use the
// anonymous callback function, with Arrow function
// syntax, and return the match (the 's' character)
// along with the index of that found character:
result = str.replace(/s/g, (match) => {
return match + i++;
});
console.log(result);
Corrected the code with the suggestion — in comments — from Ezra.
References:
Arrow functions.
"Regular expressions," from MDN.
String.prototype.replace().
For something like this, I would personally go with the split and test method. For example:
var str = "This is a simple string to test regex.";
var split = str.split(""); //Split out every char
var recombinedStr = "";
var count = 0;
for(let i = 0; i < split.length; i++) {
if(split[i] == "s") {
recombinedStr += split[i] + count;
count++;
} else {
recombinedStr += split[i];
}
}
console.log(recombinedStr);
A bit clunky, but works. It forgoes using regex statements though, so probably not exactly what you're looking for.

Get all text from a Div after a '-' up until the first character

I'm trying to write a function that will find an instance of text within a div and console.log all text that is after the '-' character. After the '-' character there are sometimes spaces and tabs, so I want to remove these up until the first text character. Here's what I have so far (that is not working at all):
var countryData = $(".countries-title").next().text();
//var regex = /(?<= - ).*/g;
let stringArray = countryData.replace(/\t/g, '').split('\r\n');
console.log(stringArray);
Any help is appreciated. Thanks
console.log('here is a - whole bunch of text'.match(/-\s*(.*)$/)[1]) will log out "whole bunch of text". Is that along the lines of what you are looking for? Let me know if you want me to elaborate.
Assuming you want to maintain all hyphens and formatting after the first hyphen and subsequent spaces you could use:
let textAfterHyphen = countryData.replace(/\s*-\s*/, '');
I am not sure if I understood all but here you have my solution:
$(document).ready(function returnString() {
$("#click-target").on("click",function(){
var newString = [];
var resultString = [];
var onlyChar =$(".target").text();
newString = onlyChar.split("");
for(var i = 0; i < newString.length; i++){
if(newString[i] == "-"){
resultString = newString.slice(i+1,newString.length).join("");
}
}
var k = 0;
for(var j = 0; j < resultString.length; j++){
if(resultString.charCodeAt(j) > 64 && resultString.charCodeAt(j) < 91){
k += j;
}
}
console.log(resultString.slice(k,resultString.length));
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="target">Text- *^^^***Text to display</div>
<button id ="click-target">Click</button>

Reverse string to find palindromes in JavaScript

I have two strings. The first is normal string, the second I want to be a reversed string like first one, but in the console I didn't get the look of like first one listed by commas. How can I fix that ?
Normal string -
Revered string -
window.onload = function(){
inputBox = document.getElementById("myText");
btn = document.getElementById('sub');
btn.addEventListener("click",function(event){
event.preventDefault();
findPalindromes(inputBox.value);
});
str = inputBox.value;
function findPalindromes(str) {
var words = str.split(" ");
for (var i = 0; i < words.length - 1; i++) {
words[i] += " ";
}
console.log(words);
var newString = "";
for (var i = words.length - 1; i >= 0; i--) {
newString += words[i];
}
console.log(newString);
}
}
If you really just want to find out if a string is a palindrome, you can do something as simple as this:
function isPalindrome(str) {
return str.toLowerCase() === str.toLowerCase().split('').reverse().join('');
}
The first for loop is not necessary. You do not need to concatenate a space character " " to the element of the array, where the variable assignment i
var i = 0;
and condition
i < words.length - 1;
stops before reaching last element of array.
var newString = "";
for (var i = words.length - 1; i >= 0; i--) {
newString += words[i] + " ";
}
console.log(newString);
In your "normal" string example, you're printing words to the console. Let's first look at what words is: var words = str.split(" ");
The String.split() function returns an array of strings. So your "normal" string is actually an array of strings (The brackets [] and comma separated strings in the console output indicate this).
In the second example, you're logging newString. Let's look at where it comes from: var newString = "";
newString is a String. If you want it to be an array of strings like words, you would declare it with var newString = [];. Arrays do not support += so newString += words[i]; would become newString.push(words[i]);
The above explains how to get newString to behave like words, the code you've written is not looking for a palindrome word, but rather a palindrome sentence: "Bob is Bob" is not a palindrome (reversed it is "boB si boB") but it could be a Palindrome sentence (if such a thing exists).
Thanks to all, I wrote this solution for the problem. I hope this is the right answer.
window.onload = function(){
inputBox = document.getElementById("myText");
btn = document.getElementById('sub');
btn.addEventListener("click",function(event){
event.preventDefault();
findPalindromes(inputBox.value);
});
str = inputBox.value;
function findPalindromes(str) {
var words = str.split(" "),
newString = [];
for (var i = 0; i < words.length - 1; i++) {
if ((words[i] === words[i].split('').reverse().join('')) === true) {
newString.push(words[i]);
}
}
console.log(newString);
}
}
var words = " ";
function reverse_arr(arr){
var i = arr.length - 1;
while(i >= 0){
words += a[i] + " ";
i--;
}
return words;
}

Retrieve substring between two characters

I have string like this
var str = "#it
itA
itB
_
#et
etA
etB
_
etC
etD"
How can I retrieve elements between # and _. As of now I am splitting the text with new line but unable to workout this. Please help me on this. Please use this fiddle http://jsfiddle.net/h728C/2/
IF you simply want the FIRST string BETWEEN you can use:
var mys= str.substring(str.indexOf('#')+1,str.indexOf("_"));
this returns: "it itA itB"
I've posted some solution in fidde. It uses the Regex
var str = $('#a').text();
var pattern = /#([\s\S]*?)(?=_)/g;
var result = str.match(pattern);
for (var i = 0; i < result.length; i++) {
if (result[i].length > 1) {
result[i] = result[i].substring(1, result[i].length);
}
alert(result[i]);
}
Strip the end and beginning.
Edit
I've updated the fiddle and the code. Now it strips the beginning # and ending _.
You can use either. Whichever is convenient.
​
​
I don't really get why but this works:
var str = $('#a').text();
var results = [];
$.each(str.split("_"), function(){
var a = this.toString().split("#");
if(a.length===2) results.push(a[1]);
});
console.log(results);​
You can use this kind of regex:
str.replace(/\s/g, "").match(/#(.*?)_/g, "$1");
See this fiddle.
one line solution to get the array
var arrStr = str.split(/[#_]/);
I would not recommend using regex here as it can be done more efficiently through other methods.
function extractString(template, initChar, finalChar) {
let i = 0;
let data = [];
do {
if (template[i] == initChar) {
for (let j = i + 1; j < template.length; j++) {
if (template[j] == finalChar) {
data[data.length] = template.slice(i + 1, j);
i = j + 1;
break;
}
}
}
}
while (++i < template.length);
console.log(data)
return data;
}
extractString("#adj#, #brown# fox jumps over the lazy #dog#.","#","#");

How can i match and replace a string and its before one letter in javascript?

var str="itss[BACK][BACK][BACK][BACK][BACK][BACK] it's a test stringgg[BACK][BACK]";
var word = '[BACK]';
var substrings = str.split(word);
var cnt= substrings.length - 1;
for(var i = 0;i<cnt;i++){
str = str.replace(/.{1}\[BACK\]{1}/i,""); //remove backspace and one character before it.
}
The above script returns something like "[BACK it's a test string" I need to get this result as "it's a test string" please help me....
It's easier to do this without a regex actually.
String.prototype.replaceFromIndex=function(index, length, replace) {
return this.substr(0, index) + replace + this.substr(index+length);
}
var search = '[BACK]';
var str="itss[BACK][BACK][BACK][BACK][BACK][BACK] it's a test stringgg[BACK][BACK]";
while((index = str.indexOf(search)) >= 0){
str = str.replaceFromIndex(index-1, search.length+1, '');
}
alert(str);
Check http://jsfiddle.net/fRThH/2/ for a working example.
Wrap it in a function and you are ready to go!
Courtesy to Cem Kalyoncu ( https://stackoverflow.com/a/1431113/187018 ) for a slightly modified version of String.prototype.replaceAt
My idea is to count all the backspaces [BACK] and then replace them with an empty string one by one:
var str="itss[BACK][BACK][BACK][BACK][BACK][BACK] it's a test stringgg[BACK][BACK]";
var backspaces = str.match(/\[BACK\]/g).length;
for(i=0; i<backspaces; i++)
{
str = str.replace(/.?\[BACK\]/, '');
}
document.write( str );
working example: jsFiddle
If I understood correctly
var dat = str.split('[BACK]').filter(function(e){return e})[1];
here is the working demo.
One of the problems that I found out was that you didn't set a condition in which you would not have to remove the first character when the string '[BACK]' is in position zero.
Well, the solution I am posting here first search for the position of the first '[BACK]' string, and then creates a substring of the characters that we want to remove, so, if there is a character before the string '[BACK]', it is included in the substring. Then, the substring is removed from the main string, and it continues looping until all the '[BACK]' s are removed.
var str = "itss[BACK][BACK][BACK][BACK][BACK][BACK] it's a test stringgg[BACK][BACK]";
var word = '[BACK]';
var substrings = str.split(word);
var cnt = substrings.length - 1;
for (i = 0; i < cnt; i++) {
pos = str.search("[BACK]");
if (pos - 1 > 0) {
str = str.replace(str.substring(pos - 2, pos + 5), '');
} else {
str = str.replace(str.substring(pos - 1, pos + 5), '');
}
}
Here is the code in jsfiddle:

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