I am doing it wrong. I know.
I want to assign the matched text that is the result of a regex to a string var.
basically the regex is supposed to pull out anything in between two colons
so blah:xx:blahdeeblah
would result in xx
var matchedString= $(current).match('[^.:]+):(.*?):([^.:]+');
alert(matchedString);
I am looking to get this to put the xx in my matchedString variable.
I checked the jquery docs and they say that match should return an array. (string char array?)
When I run this nothing happens, No errors in the console but I tested the regex and it works outside of js. I am starting to think I am just doing the regex wrong or I am completely not getting how the match function works altogether
I checked the jquery docs and they say that match should return an array.
No such method exists for jQuery. match is a standard javascript method of a string. So using your example, this might be
var str = "blah:xx:blahdeeblah";
var matchedString = str.match(/([^.:]+):(.*?):([^.:]+)/);
alert(matchedString[2]);
// -> "xx"
However, you really don't need a regular expression for this. You can use another string method, split() to divide the string into an array of strings using a separator:
var str = "blah:xx:blahdeeblah";
var matchedString = str.split(":"); // split on the : character
alert(matchedString[1]);
// -> "xx"
String.match
String.split
Related
I have this string that's. The &# substring is common but number after it changes in almost every object of my JSON data. So I want to detect if there is this substring, then get next three characters after it replace it with something else. How can I do it?
You can do it like this
var para = 'that's';
para = para.substr(para.indexOf('#')+1, 3);
syntax:
substr(start, length)
indexOf(searchvalue, [start])
Assuming you want to replace everything from &# until ; (if not, please update your question by specifying expected output):
You can use String.prototype.replace() with a regular expression:
var para = 'some string ' middle end';
para = para.replace(/&#([\d]*);/g, 'replacement');
The g modifier is important to replace all occurences in the string.
With the RegEx used, you can include the found number (between &# and ;) in the replacement string by using $1.
you can define and use a utility function to replace HTML entities like that:
function decode(text, replaceWith = '') {
return text.replace(/&#(\d+);/g, replaceWith)
}
I'm doing a small javascript method, which receive a list of point, and I've to read those points to create a Polygon in a google map.
I receive those point on the form:
(lat, long), (lat, long),(lat, long)
So I've done the following regex:
\(\s*([0-9.-]+)\s*,\s([0-9.-]+)\s*\)
I've tested it with RegexPal and the exact data I receive:
(25.774252, -80.190262),(18.466465, -66.118292),(32.321384, -64.75737),(25.774252, -80.190262)
and it works, so why when I've this code in my javascript, I receive null in the result?
var polygons="(25.774252, -80.190262),(18.466465, -66.118292),(32.321384, -64.75737),(25.774252, -80.190262)";
var reg = new RegExp("/\(\s*([0-9.-]+)\s*,\s([0-9.-]+)\s*\)/g");
var result = polygons.match(reg);
I've no javascript error when executing(with debug mode of google chrome). This code is hosted in a javascript function which is in a included JS file. This method is called in the OnLoad method.
I've searched a lot, but I can't find why this isn't working. Thank you very much!
Use a regex literal [MDN]:
var reg = /\(\s*([0-9.-]+)\s*,\s([0-9.-]+)\s*\)/g;
You are making two errors when you use RegExp [MDN]:
The "delimiters" / are should not be part of the expression
If you define an expression as string, you have to escape the backslash, because it is the escape character in strings
Furthermore, modifiers are passed as second argument to the function.
So if you wanted to use RegExp (which you don't have to in this case), the equivalent would be:
var reg = new RegExp("\\(\\s*([0-9.-]+)\\s*,\\s([0-9.-]+)\\s*\\)", "g");
(and I think now you see why regex literals are more convenient)
I always find it helpful to copy and past a RegExp expression in the console and see its output. Taking your original expression, we get:
/(s*([0-9.-]+)s*,s([0-9.-]+)s*)/g
which means that the expressions tries to match /, s and g literally and the parens () are still treated as special characters.
Update: .match() returns an array:
["(25.774252, -80.190262)", "(18.466465, -66.118292)", ... ]
which does not seem to be very useful.
You have to use .exec() [MDN] to extract the numbers:
["(25.774252, -80.190262)", "25.774252", "-80.190262"]
This has to be called repeatedly until the whole strings was processed.
Example:
var reg = /\(\s*([0-9.-]+)\s*,\s([0-9.-]+)\s*\)/g;
var result, points = [];
while((result = reg.exec(polygons)) !== null) {
points.push([+result[1], +result[2]]);
}
This creates an array of arrays and the unary plus (+) will convert the strings into numbers:
[
[25.774252, -80.190262],
[18.466465, -66.118292],
...
]
Of course if you want the values as strings and not as numbers, you can just omit the +.
I'm sorry if it is a confusing question. I was trying to find a way to do this but couldn't find it so, if it is a repeated question, my apologies!
I have a text something like this: something:"askjnqwe234"
I want to be able to get askjnqwe234 using a RegExp. You can notice I want to omit the quotes. I was trying this using /[^"]+(?=(" ")|"$)/g but it returns an array. I want a RegExt to return a single string, not an array.
I don't know if it's possible but I do not want to specify the position of the array; something like this:
var x = string.match(/[^"]+(?=(" ")|"$)/g)[0];
Thanks!
Try:
/"([^"]*)"/g
in English: look for " the match and record anything that isn't " till you see another "".
match and exec always return an array or null, so, assuming you have a single double-quoted value and no newlines in the string, you could use
var x;
var str = 'something:"askjnqwe234"';
x = str.replace( /^[^"]*"|".*/g, '' );
// "askjnqwe234"
Or, if you may have other quoted values in the string
x = str.replace( /.*?something:"([^"]*)".*/, '$1' );
where $1 refers to the substring captured by the sub-pattern [^"]* between the ().
Further explanation on request.
Notwithstanding the above, I recommend that you tolerate the array indexing and just use match.
You can capture the information inside quotes like this, assuming it matches:
var x = string.match(/something:"([^"]*)"/)[1];
The memory capture at index 1 is the part inside the double quotes.
If you're not sure it will match:
var match = string.match(/something:"([^"]*)"/);
if (match) {
// use match[1] here
}
I have a string that looks something like this
Hey this is my 1.20 string
I'm trying to just extract 1.20 from it.
What's the best way to do this?
I've tried something like this, but I get the value of 1.20,20 rather than just 1.20
var query = $(".query_time").html();
var matches = query.match(/\d.(\d+)/);
The result of the match function is an array, not a string. So simply take
var nb = query.match(/\d.(\d+)/)[0];
BTW, you should also escape the dot if you want to have more precise match :
var nb = query.match(/\d\.(\d+)/)[0];
or this if you want to accept commas (depends on the language) :
var nb = query.match(/\d[\.,](\d+)/)[0];
But the exact regex will be based on your exact needs, of course and to match any number (scientific notation ?) I'd suggest to have a look at more complex regex.
The value of matches is actually [ "1.20", "20" ] (which is an array). If you print it, it will get converted to a string, hence the 1.20,20.
String.match returns null or an array of matches where the first index is the fully matched part and then whichever parts you wanted. So the value you want is matches[0].
Try the following
var nb = query.match(/\d\.\d+/)[0]; // "1.20"
You need to escape . because that stands for any character.
Remove the capture group (\d+) and the second match is not returned
Add [0] index to retrieve the match
For example, I have a string:
"This is the ### example"
I would like to substring the ### out of the above string?
The number of Hash keys may vary, so I would like to find out and replace the ### pattern with, say, 001 for example.
Can anybody help?
You can also do a replace. I am familiar with the C# version of this,
string stringValue = "Thia is the ### example";
stringValue.Replace("###", "");
This would remove ### completely from the above string. Again you would have to know the exact string.
In JavaScript, it's similar - .replace (with a lowercase r) is used. So:
var stringValue = "This is the ### example";
var replacedValue = stringValue.replace('###', '');
You'll want to investigate either "Regular Expressions" for this, or, if you know the precise position and length of the characters you are interested in, you can simply use String's .substring method.
If you want to capture multiple # characters, then you'll need regular expressions:
var myString = "This is #### the example";
var result = myString.replace(/#+/g, '');
If you want to remove the space too, you can use the regex /#+\s|\s#+|#+/.
If the rest of the string is known, just get the part that you need:
var example = str.substr(12, str.length - 20);
The javascript match method will return an array of substrings matching a regular expression. You can use this to determine the number of matching characters to be replaced. Assuming you want to replace each octothorpe with a random digit, you could use code like this:
var exampleStr = "This is the ### example";
var swapThese = exampleStr.match(/#/g);
if (swapThese) {
for (var i=0;i<swapThese.length;i++) {
var swapThis = new RegExp(swapThese[i]);
exampleStr = exampleStr.replace(swapThis,Math.floor(Math.random()*9));
}
}
alert(exampleStr); // or whatever you want to do with it
Note that the code only loops the length of the array if it's present: if (swapThese) {
This check is necessary because if the match method finds no matches, it returns null rather than an empty array. Trying to iterate through null value will break.