I'm trying to use classList.replace() with regular expression. My goal is replacing an expression like badge-something with an other value like badge-success.
I've tried this:
element.classList.replace(/badge-*/i, 'badge-success')
But it returns false and doesn't change nothing. What am I missing?
Element.classList is a DOMTokenList (not a string).
DOMTokenList.replace takes two strings, not a regex. The first argument is the exact class name you want to replace. Patterns are not supported.
If you want to use regexes, you need a string:
element.className = element.className.replace(/(^|\s)badge-\S+/g, '$1badge-success');
classList.replace took string as an argument, so i think that is why it is not working.
But you can achieve your goal by twisting your code little bit,
repeat these steps
first took all className of that element(using element.className)
split those classes in array (using split function--- classname.split(' '))
apply forEach loop on array and by using str.search('badge-') > -1, replace that className using element.classList.replace..........Simple little long but code will work definitly
.
Thank you
Related
I think this is a very basic question, but I really can't understand the concept. I have the following regular expression:
var t = '11:59 am';
t.match(/^(\d+)/);
Now, according to my understanding when I print the value I should just get 11 since I am just checking for digits. However, I get 11,11. I have to use 0th element to pick the required value like t.match(/^(\d+)/)[0].
This is because you are using a capture group, (), around the digits. Try replacing this with:
t.match(/^\d+/);
Note: this will still return an array, because that's just what .match() does.
match() always returns an array if there are any matches. Element [0] is the whole match, and element [1] is what is inside the first set of parentheses.
I want to know how can I get a regular expression for matching number, ., and - only.
I am using this:
/^[0-9\.'S]+$/
by this it working fine but not working for symbol "-".
You simply haven't used the literal dash - (or minus) in the regex. Try:
/^[0-9\.-]+$/
But if you want a proper number, you might want to use a more proper regex:
/^-?[0-9]+(?:\.[0-9]+)?$/
The first regex can accept things such as 3987----.... while the second will not accept it, but will accept things like -87.983274.
That's because - is not part of your character class. You are only using - in the class range (which only includes digits). Also, I don't know what the S and the ' are doing there:
/^[0-9.-]+$/
Also, I can promise you that after taking the time to read through this tutorial regular expressions will seem a lot less confusing to you.
Try the below regex.
/^-?[0-9\.]+$/
I am trying to get just a part of a string with a regex
this is the string i am testing
class1 container _box _box_CEC493
the string is a series of classes applied to an element.
what i would like to get is just CEC493 which changes since the regex will be applied to a bunch of different elements (therefore string like the one above)
the regex i am using now is
/\s_box_([0-9a-zA-Z]+)/
which returns
_box_CEC493, CEC493
How can i modify it in order to get just the second value (CEC493)?
Thank you
You could probably just split the string:
var str = "class1 container _box _box_CEC493";
var match = str.split('_').pop();
alert(match);
DEMO
The standard way regexes come back is like this:
[0]: Whole result
[1]: First parentheses capture group
etc
So the standard way that people access these is with result[1]. Does that cause any issues in your case?
[updated]
instead of selecting all characters, select until an unwanted character,, and since you are selecting from a number of classes, it is possible that you have the _box_.. class alone without a space before it, so don't use space at the beginning of your regex selector.
str.match(/_box_([^\s]*)/)[1]
jsfiddle
Say I have a string "&something=variable&something_else=var2"
I want to match between &something= and &, so I'll write a regular expression that looks like:
/(&something=).*?(&)/
And the result of .match() will be an array:
["&something=variable&", "&something=", "&"]
I've always solved this by just replacing the start and end elements manually but is there a way to not include them in the match results at all?
You're using the wrong capturing groups. You should be using this:
/&something=(.*?)&/
This means that instead of capturing the stuff you don't want (the delimiters), you capture what you do want (the data).
You can't avoid them showing up in your match results at all, but you can change how they show up and make it more useful for you.
If you change your match pattern to /&something=(.+?)&/ then using your test string of "&something=variable&something_else=var2" the match result array is ["&something=variable&", "variable"]
The first element is always the entire match, but the second one, will be the captured portion from the parentheses, which is much more useful, generally.
I hope this helps.
If you are trying to get variable out of the string, using replace with backreferences will get you what you want:
"&something=variable&something_else=var2".replace(/^.*&something=(.*?)&.*$/, '$1')
gives you
"variable"
I am trying to find a way to check if a string contains a specific sequence of characters in JScript.
In my case, I am trying to see if the string is "DPObject" followed by a number. Such as "DPObject3" or "DPObject14".
Thank you!
if (/DPObject\d+/.test(string)) {....}
Javascript String has an indexOf method you can use to check if a String contains a particular substring .
If you need to test for patterns , like "DPObject" followed by an integer , probably you need to use Regexes . ( http://www.regular-expressions.info )
It's javascript , or js for short - not JScript .
Then you should use a regular expression. I think this would be something like :
var re = new RegExp("^DPObject([0-9]+)$");
re.test(someString);
This ensures there is at least only one digit after DPObject.
The "^" at the beginning is to ensure the string starts with DPObject. Check references on regexps for this kind of problems :)
edit: added "$" to mark the end of the string, the updated should be more "solid"
There are a couple of ways:
Use Javascripts indexOf method
Use Javascript Regular Expressions
Use JQuery's contains function
Regular expressions are the most powerful and elegant way of doing it. They syntax makes sense after a while (honestly). ;-)
Good luck.