Develop Reference

What is the best way to get a part of a string from a given string using javascript

I have a string in JavaScript like this:
var str = "1:A;2:B;3:A;4:c;5:D";
How to retreive option in front of 2, that is B.
Presently am getting this using for loop by splitting the string every ;,
but I want to know if there is any better way to achieve this without using looping concept.

You can use the split function, as below;
var str = "1:A;2:B;3:A;4:c;5:D";
var result = str.split(":");
document.getElementById("Location").innerHTML = res[2];

If you know that this will be a pattern you can use something like:
var str = "1:A;2:B;3:A;4:c;5:D";
var i = 2;
console.log(str[str.indexOf(i)+2]);
//Output "B"

If you wanted to get the option in front of 2 you could use either:
a loop (preferred in my option)
indexOf
Javascript:
function getAnswer(str) {
var position = str.indexOf(';2:')
// not found in string, or '2' is the first answer
if(position === -1) {
return;
}
return str.substring(position - 1, position)
}

Might be recursive approach help you.
var str = "1:A;2:B;3:A;4:c;5:D",
arr = str.split(";"),
len = arr.length;
function getVal(len){
if(len !== 0){
getVal(len-1);
if(arr[len-1].indexOf(2) === 0){
console.log(arr[len-1].split(":")[1])
};
};
};
getVal(len);

RegExp
var num = '2';
"1:A;2:B;3:A;4:c;5:D".match((new RegExp(num+"\\:([\\S\\s]+?)\\;", "")))[1];
Fiddle
This uses RegExp (Regular Expressions) What this does is it will look for a '2' in the string, then get the option associated with it
Substring
I couldn't think of a better word so forgive me. You can use substring and .indexOf()
var num = '2',
string = "1:A;2:B;3:A;4:c;5:D",
index = string.indexOf(num+':');
string.substring(index+num.length+1,index+num.length+2);
Fiddle
Similar
The substring answer is a little easier to understand but the following does the sameish
var num = '2',
string = "1:A;2:B;3:A;4:c;5:D";
string[string.indexOf(num+':')+num.length+1];
Fiddle
Foolproof
This should work in most situations. This will also get the option if it is more than one letter long
var string = "1:A;2:B;3:A;4:c;5:D",
num = '2',
result;
if (string.indexOf(';'+num+':') < 0) {
result = string.match(new RegExp(num+"\\:([\\S\\s]+?)\\;", ""))[1];
} else {
result = string.match((new RegExp('\\;'+num+"\\:([\\S\\s]+?)\\;", "")))[1];
}
Shorter:
var string = "1:A;2:B;3:A;4:c;5:D", num = '2', result = string.indexOf(";"+num+":") < 0? string.match(new RegExp(num+"\\:([\\S\\s]+?)\\;",""))[1] : string.match(new RegExp("\\;"+num+"\\:([\\S\\s]+?)\\;",""))[1];
alert(result);
Fiddle (I have made it a one-liner)

Regex remove repeated characters from a string by javascript

I have found a way to remove repeated characters from a string using regular expressions.
function RemoveDuplicates() {
var str = "aaabbbccc";
var filtered = str.replace(/[^\w\s]|(.)\1/gi, "");
alert(filtered);
}
Output: abc
this is working fine.
But if str = "aaabbbccccabbbbcccccc" then output is abcabc.
Is there any way to get only unique characters or remove all duplicates one?
Please let me know if there is any way.

A lookahead like "this, followed by something and this":
var str = "aaabbbccccabbbbcccccc";
console.log(str.replace(/(.)(?=.*\1)/g, "")); // "abc"
Note that this preserves the last occurrence of each character:
var str = "aabbccxccbbaa";
console.log(str.replace(/(.)(?=.*\1)/g, "")); // "xcba"
Without regexes, preserving order:
var str = "aabbccxccbbaa";
console.log(str.split("").filter(function(x, n, s) {
return s.indexOf(x) == n
}).join("")); // "abcx"

This is an old question, but in ES6 we can use Sets. The code looks like this:
var test = 'aaabbbcccaabbbcccaaaaaaaasa';
var result = Array.from(new Set(test)).join('');
console.log(result);

Remove character from string using javascript

i have comma separated string like
var test = 1,3,4,5,6,
i want to remove particular character from this string using java script
can anyone suggests me?

JavaScript strings provide you with replace method which takes as a parameter a string of which the first instance is replaced or a RegEx, which if being global, replaces all instances.
Example:
var str = 'aba';
str.replace('a', ''); // results in 'ba'
str.replace(/a/g, ''); // results in 'b'
If you alert str - you will get back the same original string cause strings are immutable.
You will need to assign it back to the string :
str = str.replace('a', '');

Use replace and if you want to remove multiple occurrence of the character use
replace like this
var test = "1,3,4,5,6,";
var newTest = test.replace(/,/g, '-');
here newTest will became "1-3-4-5-6-"

you can make use of JavaScript replace() Method
var str="Visit Microsoft!";
var n=str.replace("Microsoft","My Blog");

var test = '1,3,4,5,6';​​
//to remove character
document.write(test.replace(/,/g, ''));
//to remove number
function removeNum(string, val){
var arr = string.split(',');
for(var i in arr){
if(arr[i] == val){
arr.splice(i, 1);
i--;
}
}
return arr.join(',');
}
var str = removeNum(test,3);
document.write(str); // output 1,4,5,6

You can also
var test1 = test.split(',');
delete test1[2];
var test2 = test1.toString();
Have fun :)

you can split the string by comma into an array and then remove the particular element [character or number or even string] from that array. once the element(s) removed, you can join the elements in the array into a string again
// Array Remove - By John Resig (MIT Licensed)
Array.prototype.remove = function(from, to) {
var rest = this.slice((to || from) + 1 || this.length);
this.length = from < 0 ? this.length + from : from;
return this.push.apply(this, rest);
};

You can use this function
function removeComma(inputNumber,char='') {
return inputNumber.replace(/,/g, char);
}
Update
function removeComma(inputNumber) {
inputNumber = inputNumber.toString();
return Number(inputNumber.replace(/,/g, ''));
}

Separate by comma (,) and check if any of the values is = "something"

How can I somehow split/separate my JavaScript variable by comma (,).
And then check if value-of-any-of-the-separated-strings = "something"
For example, my variable has the value 1,2,3,4,5,6,7,8,9,10,2212312, and I want to check if any of the numbers are = 7 in a IF-Statement.
Does anyone have any ideas how this can be done?

First, split the string by ",". Then, use indexOf on the split-string array to see if the target string is found (-1 means it wasn't found in the array). For example:
var str = "1,2,3,4,5,6,7,8,9,10,10,2212312";
var split_str = str.split(",");
if (split_str.indexOf("7") !== -1) {
// Original string contains 7
}
References:
String.prototype.split - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split
Array.prototype.indexOf - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf

This is a simple application of Array.prototype.some:
var yourVar = '1,2,3,4,5,6,7,8,9,10,2212312';
function isSeven(val) {
return val === '7';
}
if (yourVar.split(',').some(isSeven)) {
//do stuff
}
Another common way this could be written is:
if (~yourVar.split(',').indexOf('7')) {
//do stuff
}
Or if Array.prototype.contains has been defined:
if (yourVar.split(',').contains('7')) {
//do stuff
}
Or if you want to use a regular expression:
if (/(?:^|,)7(?:,|$)/.test(yourVar)) {
//do stuff
}
Note: Array.prototype.some, Array.prototype.indexOf and Array.prototype.contains all require polyfills to work correctly cross browser.

Split it into an Array, then use indexOf to see if it's there. If it returns -1, it isn't.
"1,2,3,4,5,6,7,8,9,10,2212312".split(",").indexOf("7")

man i hope it will help you.
var yourValues = '1,2,3,4,5,6,7,8,9,10,2212312';
var array = yourValues.split(",");
boolean isValue = false;
for(i in array)
{
if(array[i]=='7')
{
isValue=true;
}
}
if(isValue)
alert("your number is in the string");
else
alert("your number is in the string");

You could use Array.filter, something like:
var values = '1,2,3,4,5,6,7,8,9,10,2212312'.split(','), find = 7;
if ( values.filter(function(a){return +a === find;}).length ) { /* ... */ }

Use split and Array.indexOf()
var str = "1,2,3,4,5,6,7,8,9,10,2212312";
var num = 7;
var pieces = str.split(",");
var index = pieces.indexOf(num.toString());
It can be done with regular expressions too
var str = "1,2,3,4,5,6,7,8,9,10,2212312";
var num = 7;
var re = new RegExp("(^|,)" + num + "($|,)");
alert(re.test(str));
jsFiddle example

use split along with indexOf:
var someString = '1,2,3,4,5,6,7,8,9,10,2212312';
var splitArray = someString.split(',');
var sevenPosition = splitArray.indexOf('7');
http://jsfiddle.net/jbabey/f4NLY/

Are you looking for the "contains" function. You can use jQuery for this.
if ($.inArray(7, value-of-any-of-the-seperated-strings))
{
console.log("there is a 7!")
}

Remove a letter(:) from a string

I have strings like Name:, Call:, Phone:....and so on in my table. I am learning jQuery and was able to access the text. My tutorial has used trim() to remove any whitespaces. But I want o remove ":" from the end of each string (and yes, it always lies in the end after calling trim() method). So how to achieve it.
Its my code:
<script type="text/javascript">
$(function ()
{
$(':input[type=text], textarea').each
(
function ()
{
var newText = 'Please enter your ' +
$(this).parent().prev().text().toLowerCase().trim();
$(this).attr('value', newText);
}).one('focus', function ()
{
this.value = '', this.className = ''
}).addClass('Watermark').css('width', '300px');
});
</script>
trim(":") did not help...

You can replace all : characters:
var str = '::a:sd:';
str = str.replace(/:/g,''); // str = 'asd';
Or use a handy rtrim() function:
String.prototype.rtrim = function(character) {
var re = new RegExp(character + '*$', 'g');
return this.replace(re, '');
};
var str = '::a:sd:';
str = str.rtrim(':'); // str = '::a:sd';

In this case just use the plain old JavaScript replace or substr methods.
You can also use a regular expression that looks for colon as the last character (the character preceding the regexp end-of-string anchor "$").
"hi:".replace(/:$/, "")
hi
"hi".replace(/:$/, "")
hi
"h:i".replace(/:$/, "")
h:i
This is a simplified, inline version of the rtrim function in Blender's answer.
EDIT: Here is a test fiddle for Blender's corrected rtrim function. Note that his RegExp will delete multiple occurrences of the specified character if the string ends with multiple instances of it consecutively (example bolded below).
http://jsfiddle.net/fGrPb/5/
input = '::a:sd:' output = '::a:sd'; input = 'hi:' output = 'hi'; input = 'hi:::' output = 'hi'; input = 'hi' output = 'hi'; input = 'h:i' output = 'h:i'

To chop the last character of a string use string.slice(0,-1)

You can use a regular expression to remove the colon (:).
Replace one instance:
var with_colon = 'Stuff:';
var regex = /([^:]*):/;
var without_colon = regex.exec(with_colon)[1];
alert(without_colon);
Result: Stuff
Replace all instances:
var with_colon = 'Stuff: Things:';
var without_colon = with_colon.replace(/([^:]*):/g,'$1');
alert(without_colon);
Result: Stuff Things

var myStr = "something:";
myStr = myStr.slice(0, -1);

var a="name:";
var b=a.split(":");
alert(b[0]);

one way is to use lastIndexOf
var str='Name:, Call:, Phone:';
var index=str.lastIndexOf(":");
alert(index);
var s=str.substring(0,index);
alert(s);
DEMO

This checks if the last character is a colon. If it is, the last character is removed.
if (str[str.length - 1] === ":") {
str = str.slice(0, -1);
}
If there can be multiple trailing colons, you can replace if with while, like this:
while (str[str.length - 1] === ":") {
str = str.slice(0, -1);
}
You could even make a generic trim function that accepts a string and a character and trims trailing instances of that character:
var trim = function(str, chr) {
while (str[str.length - 1] === ":") {
str = str.slice(0, -1);
}
return str;
}

function trim(str) {
str = str.replace(/^:*/,"");
return str.replace(/:*$/,"");
}

str = str.substring(0,str.lastIndexOf(":"));
Note that this removes everything from the last : to the end of the string (for example, any whitespace after the :).