Splitting a string at special character with JavaScript - javascript

I am trying to "intelligently" pre-fill a form, I want to prefill the firstname and lastname inputs based on a user email address, so for example,
jon.doe#email.com RETURNS Jon Doe
jon_doe#email.com RETURN Jon Doe
jon-doe#email.com RETURNS Jon Doe
I have managed to get the string before the #,
var email = letters.substr(0, letters.indexOf('#'));
But cant work out how to split() when the separator can be multiple values, I can do this,
email.split("_")
but how can I split on other email address valid special characters?

JavaScript's string split method can take a regex.
For example the following will split on ., -, and _.
"i-am_john.doe".split(/[.\-_]/)
Returning the following.
["i", "am", "john", "doe"]

You can use a regular expression for what you want to split on. You can for example split on anything that isn't a letter:
var parts = email.split(/[^A-Za-z]/);
Demo: http://jsfiddle.net/Guffa/xt3Lb9e6/

You can split a string using a regular expression. To match ., _ or -, you can use a character class, for example [.\-_]. The syntax for regular expressions in JavaScript is /expression/, so your example would look like:
email.split(/[\.\-_]/);
Note that the backslashes are to prevent . and - being interpreted as special characters. . is a special character class representing any character. In a character class, - can be used to specify ranges, such as [a-z].
If you require a dynamic list of characters to split on, you can build a regular expression using the RegExp constructor. For example:
var specialChars = ['.', '\\-', '_'];
var specialRegex = new RegExp('[' + specialChars.join('') + ']');
email.split(specialRegex);
More information on regular expressions in JavaScript can be found on MDN.

Regular Expressions --
email.split(/[_\.-]/)
This one matches (therefore splits at) any of (a character set, indicated by []) _, ., or -.
Here's a good resource for learning regular expressions: http://qntm.org/files/re/re.html

You can use regex to do it, just provide a list of the characters in square brackets and escape if necessary.
email.split("[_-\.]");
Is that what you mean?

You are correct that you need to use the split function.
Split function works by taking an argument to split the string on. Multiple values can be split via regular expression. For you usage, try something like
var re = /[\._\-]/;
var split = email.split(re, 2);
This should result in an array with two values, first/second name. The second argument is the number of elements returned.

I created a jsFiddle to show how this could be done :
function printName(email){
var name = email.split('#')[0];
// source : http://stackoverflow.com/questions/650022/how-do-i-split-a-string-with-multiple-separators-in-javascript
var returnVal = name.split(/[._-]/g);
return returnVal;
}
http://jsfiddle.net/ts6nx9tt/1/

If you define your seperators, below code can return all alternatives for you.
var arr = ["_",".","-"];
var email = letters.substr(0, letters.indexOf('#'));
arr.map(function(val,index,rest){
var r = email.split(val);
if(r.length > 1){
return r.join(' ');
}
return "";
}
);

Related

javascript regex replace all occurrences, using variables & dynamic strings [duplicate]

I am trying to search a single whole word through a textbox. Say I search "me", I should find all occurrences of the word "me" in the text, but not "memmm" per say.
I am using JavaScript's search('my regex expression') to perform the current search (with no success).
After several proposals to use the \b switches (which don't seem to work) I am posting a revised explanation of my problem:
For some reason this doesn't seem to do the trick. Assume the following JavaScript search text:
var lookup = '\n\n\n\n\n\n2 PC Games \n\n\n\n';
lookup = lookup.trim() ;
alert(lookup );
var tttt = 'tttt';
alert((/\b(lookup)\b/g).test(2));
Moving lines is essential
To use a dynamic regular expression see my updated code:
new RegExp("\\b" + lookup + "\\b").test(textbox.value)
Your specific example is backwards:
alert((/\b(2)\b/g).test(lookup));
Regexpal
Regex Object
Use the word boundary assertion \b:
/\bme\b/
You may use the following code:
var stringTosearch ="test ,string, test"; //true
var stringTosearch ="test string test"; //true
var stringTosearch ="test stringtest"; //false
var stringTosearch ="teststring test"; //false
if (new RegExp("\\b"+"string"+"\\b").test(stringTosearch)) {
console.log('string found');
return true;
} else {
return false;
}
<script type='text/javascript'>
var lookup = '\n\n\n\n\n\n2 PC Games \n\n\n\n';
lookup = lookup.trim() ;
alert(lookup );
var tttt = 'tttt';
alert((/\b(lookup)\b/g).test(2));
</script>
It's a bit hard to tell what you're trying to do here. What is the tttt variable supposed to do?
Which string are you trying to search in? Are you trying to look for 2 within the string lookup? Then you would want:
/\b2\b/.test(lookup)
The following, from your regular expression, constructs a regular expression that consists of a word boundary, followed by the string "lookup" (not the value contained in the variable lookup), followed by a word boundary. It then tries to match this regular expression against the string "2", obtained by converting the number 2 to a string:
(/\b(lookup)\b/g).test(2)
For instance, the following returns true:
(/\b(lookup)\b/g).test("something to lookup somewhere")

Get replaced characters with javascript regex replace

I am currently replacing all non-letter characters using
var stringwithoutspecialCharacter = "testwordwithpunctiuation.".replace(/[^\w\s!?]/g, '');
The problem is that I do not know which special character will appear (that needs removing). However I do need to be able to access the removed special character after I've run some code with the word without the special character.
Example inputs:
"test".
(temporary)
foo,
Desired output:
['"','test','"',"."]
['(','temporary',')']
['foo',',']
How could this be achieved in javascript?
Edit: To get both valid and invalid characters, change the regular expression
Quick solution is to define an array to collect the matches.
Then pass in a function into your replace() call
var matches = [];
var matcher = function(match, offset, string) {
matches.push(match);
return '';
}
var stringwithoutspecialCharacter = "testwordwithpunctiuation.".replace(/[^\w\s!?]|[\w\s!?]+/g, matcher);
console.log("Matches: " + matches);

How to remove the special characters from a string using javascript

I have the below String value to be displayed in text area and i want to remove the first characters ##*n|n from the string .
The string is as follows :
Symbol-001
##*n|nClaimant Name
##*n|nTransaction
I have used the below code to deal with removing the special characters
var paramVal1 = parent.noteText; //paramVal1 will have the string now
var pattern = /[##*n|n]/g;
var paramVal1 = paramVal1.replace(pattern,'');
document.getElementById("txtNoteArea").value = paramval1;//appending the refined string to text area
For the above used code am getting the out put string as below
Symbol-001
|Claimat Name //here 'n' is missing and i have an extra '|' character
|Transactio //'n' is missing here too and an extra '|' character
Kindly help to remove the characters ##*n|n without affecting the other values
What your regex is saying is "remove any of the following characters: #|*n". Clearly this isn't what you want!
Try this instead: /##\*n\|n/g
This says "remove the literal string ##*n|n". The backslashes remove the special meaning from * and |.
You are using regular expression reserved chars in your pattern, you need to escape them
You can use this expression:
var pattern = /[\#\#\*n\|n]/g;
i think use this /[##*n\|n]/g regEx
If you want to replace the first occurrence as you say on your question, you don't need to use regex. A simple string will do, as long as you escape the asterisk:
var str = "Symbol-001 ##*n|nClaimant Name ##*n|nTransaction";
var str2 = str.replace("##\*n|n", ""); //output: "Symbol-001 Claimant Name ##*n|nTransaction"
If you want to replace all the occurrences, you can use regex, escaping all the characters that have a special meaning:
var str3 = str.replace(/\#\#\*n\|n/g, ""); //output: "Symbol-001 Claimant Name Transaction"
Have a look at this regex builder, might come in handy - http://gskinner.com/RegExr/

Split each string from any given paragraph in javascript

I have a textArea. I am trying to split each string from a paragraph, which has proper grammar based punctuation delimiters like ,.!? or more if any.
I am trying to achieve this using Javascript. I am trying to get all such strings in that using the regular expression as in this answer
But here, in javascript for me it's not working. Here's my code snippet for more clarity
$('#split').click(function(){
var textAreaContent = $('#textArea').val();
//split the string i.e.., textArea content
var splittedArray = textAreaContent.split("\\W+");
alert("Splitted Array is "+splittedArray);
var lengthOfsplittedArray = splittedArray.length;
alert('lengthOfText '+lengthOfsplittedArray);
});
Since its unable to split, its always showing length as 1. What could be the apt regular expression here.
The regular expression shouldn't differ between Java and JavaScript, but the .split() method in Java accepts a regular expression string. If you want to use a regular expression in JavaScript, you need to create one...like so:
.split(/\W+/)
DEMO: http://jsfiddle.net/s3B5J/
Notice the / and / to create a regular expression literal. The Java version needed two "\" because it was enclosed in a string.
Reference:
https://developer.mozilla.org/en-US/docs/JavaScript/Guide/Regular_Expressions
You can try this
textAreaContent.split(/\W+/);
\W+ : Matches any character that is not a word character (alphanumeric & underscore).
so it counts except alphanumerics and underscore! if you dont need to split " " (space) then you can use;
var splittedArray = textAreaContent.split("/\n+/");

How do I make a regular expression that matches everything on a line after a given character?

If I have a String in JavaScript
key=value
How do I make a RegEx that matches key excluding =?
In other words:
var regex = //Regular Expression goes here
regex.exec("key=value")[0]//Should be "key"
How do I make a RegEx that matches value excluding =?
I am using this code to define a language for the Prism syntax highlighter so I do not control the JavaScript code doing the Regular Expression matching nor can I use split.
Well, you could do this:
/^[^=]*/ // anything not containing = at the start of a line
/[^=]*$/ // anything not containing = at the end of a line
It might be better to look into Prism's lookbehind property, and use something like this:
{
'pattern': /(=).*$/,
'lookbehind': true
}
According to the documentation this would cause the = character not to be part of the token this pattern matches.
use this regex (^.+?)=(.+?$)
group 1 contain key
group 2 contain value
but split is better solution
.*=(.*)
This will match anything after =
(.*)=.*
This will match anything before =
Look into greedy vs ungreedy quantifiers if you expect more than one = character.
Edit: as OP has clarified they're using javascript:
var str = "key=value";
var n=str.match(/(.*)=/i)[1]; // before =
var n=str.match(/=(.*)/i)[1]; // after =
var regex = /^[^=]*/;
regex.exec("key=value");

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