What is the JavaScript equivalent of preg_match? [duplicate] - javascript

This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
How can i use preg_match in jQuery?
What is the jquery equivalent of the PHP preg_match feature?
In PHP it would be :
preg_match('/[^a-zA-Z0-9]/', $str);
Which checks if the string has anything other than letters and numbers.
I'd like to add some client sided validation to my site, but I've looked and looked and can't quite find the jQuery equivalent of this.
Thanks.

In plain JavaScript (no jQuery needed for this), you would just use the .match() method of the string object which will return null if no matches and an array if there are matches:
var str = "myteststring";
if (str.match(/[^a-zA-Z0-9]/)) {
// contains illegal characters
}

not jQuery but JavaScript
var myStr = "something";
/[^a-zA-Z0-9]/.test(myStr) // will return true or false.
or for clarity
var regEx=/[^a-zA-Z0-9]/;
regEx.test(myStr)
The test method is part of the RegEx object... Here is some reference
http://www.w3schools.com/jsref/jsref_regexp_test.asp

If you want to match on a string, you can do it with vanilla JS:
var str = "here's my string";
var matches = str.match('/[^a-zA-Z0-9]/');
If you're trying to do it on a selector, and using jQuery, you can use:
$("div:match('/[^a-zA-Z0-9]/')")

Related

Pattern check returning false javascript/typescript [duplicate]

This question already has answers here:
JavaScript RegExp objects
(5 answers)
Closed 6 years ago.
I am trying to validate if a string I entered matches the date format 'MM/yyyy'
Below is a sample of the code I am using for the same:
var date='05/2016'
var patt= new RegExp('^((0[1-9])|(1[0-2])|[1-9])\/(\d{4})$');
patt.test(date);
However the above code is returning false.
I tried running it with the regex checker:
https://regex101.com/
The pattern seems to be working fine.
Could someone please let me know what is missing.
https://jsfiddle.net/ymj6o8La/
You have to escape the string that is passed to RegExp (the backslashes).
var patt= new RegExp('^((0[1-9])|(1[0-2])|[1-9])\\/(\\d{4})$');
Even better, in your case, it's not dynamic, so you should use the literal RegExp instead
var patt = /^((0[1-9])|(1[0-2])|[1-9])\/(\d{4})$/
You should escape your backslashes. To represent \d or even \ you should another backslash behind it (e.g: \\) :
var date = '05/2016'
var patt = new RegExp('^((0[1-9])|(1[0-2])|[1-9])\\/(\\d{4})$');
console.log(patt.test(date));
Try using a pattern like this
patt= /^((0[1-9])|(1[0-2]))\/(\d{4})$/;

Spliting numbers out of a string contain characters and numbers [duplicate]

This question already has answers here:
Extract numbers from a string using javascript
(4 answers)
Closed 6 years ago.
I want to split the numbers out of a string and put them in an array using Regex.
For example, I have a string
23a43b3843c9293k234nm5g%>and using regex I need to get [23,43,3843,9293,234,5]
in an array
how can i achieve this?
Use String.prototype.match()
The match() method retrieves the matches when matching a string against a regular expression
Edit: As suggested by Tushar, Use Array.prototype.map and argument as Number to cast it as Number.
Try this:
var exp = /[0-9]+/g;
var input = "23a43b3843c9293k234nm5g%>";
var op = input.match(exp).map(Number);
console.log(op);
var text = "23a43b3843c9293k234nm5g%>";
var regex = /(\d+)/g;
alert(text.match(regex));
You get a match object with all of your numbers.
The script above correctly alerts 23,43,3843,9293,234,5.
see Fiddle http://jsfiddle.net/5WJ9v/307/

RegEx: Extract GET variable from URL [duplicate]

This question already has answers here:
How can I get query string values in JavaScript?
(73 answers)
Closed 9 years ago.
RegExp gurus, heed my call!
This is probably super simple, but I've painted myself in a mental corner.
Taking a regular URL, split after the ?, which gives a string like variable=val&interesting=something&notinteresting=somethingelse I want to extract the value of interesting.
The name of the variable I'm interested in can be a substring of another variable.
So the match should be
either beginning of string or "&" character
followed by "interesting="
followed by the string I want to capture
followed by either another "&" or end of string
I tried something along the lines of
[\^&]interesting=(.*)[&$]
but I got nothing...
Update
This is to be run in a Firefox addon on every get request, meaning that jQuery is not available and if possible I would like to avoid the extra string manipulation caused by writing a function.
To me this feels like a generic "extract part of a string with regex" but maybe I'm wrong (RegEx clearly isn't my strong side)
simple solution
var arr = "variable=val&interesting=something&notinteresting=somethingelse".split("&");
for(i in arr) {
var splits = arr[i].split("=");
if(splits[0]=="interesting") alert(splits[1]);
}
also single line match
"variable=val&interesting=something&notinteresting=somethingelse".match(/(?:[&]|^)interesting=((?:[^&]|$)+)/)[1]
function getValue(query)
{
var obj=location.search.slice(1),
array=obj.split('&'),
len=array.length;
for(var k=0;k<len;k++)
{
var elm=array[k].split('=');
if(elm[0]==query)return elm[1];
}
}
This function directly extract the query URL and return the corresponding value if present.
//usage
var get=getValue('interesting');
console.log(get);//something
If you're using the Add-on SDK for Firefox, you can use the url module:
https://addons.mozilla.org/en-US/developers/docs/sdk/latest/modules/sdk/url.html
This is much better than using regex.

Removing any character besides 0-9 + - / * and ^ [duplicate]

This question already has answers here:
Replace method doesn't work
(4 answers)
Closed 4 years ago.
I'm trying to further my understanding of regular expressions in JavaScript.
So I have a form that allows a user to provide any string of characters. I'd like to take that string and remove any character that isn't a number, parenthesis, +, -, *, /, or ^. I'm trying to write a negating regex to grab anything that isn't valid and remove it. So far the code concerning this issue looks like this:
var pattern = /[^-\+\(\)\*\/\^0-9]*/g;
function validate (form) {
var string = form.input.value;
string.replace(pattern, '');
alert(string);
};
This regex works as intended on http://www.infobyip.com/regularexpressioncalculator.php regex tester, but always alerts with the exact string I supply without making any changes in the calculator. Any advice or pointers would be greatly appreciated.
The replace method doesn't modify the string. It creates a new string with the result of the replacement and returns it. You need to assign the result of the replacement back to the variable:
string = string.replace(pattern, '');

how to replace all %s string in javascript [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
JavaScript equivalent to printf/string.format
replace all occurrences in a string
see title. see the following variable, how can i replace all '%s' with other string?
var s = 'qwer%sqwer%s';
please advice
Use .replace method.
var s = 'qwer%sqwer%s';
s = s.replace(/%s/g, 'other');
Try this:
s.replace(/%s/g,'x')
You can Use replace() function for replacing string
Ex.
var getnewstring = s.replace("%s","YOUR STRING");
Use the .replace method
var s = 'qwer%sqwer%s';
s=s.replace('%s','your string')
document.write(s);

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