This question already has answers here:
How do you use a variable in a regular expression?
(27 answers)
Why this javascript regex doesn't work?
(1 answer)
Closed 4 years ago.
Trying to replace all a's in the string ignoring the case.
str = "All a's will be replaced";
str.replace(/a/gi, 'Aa');
As expected, the above line of code produces Aall Aa's will be replAaced
But,
regExp = new RegExp('/a/gi');
str.replace(regExp, 'Aa');
the above line with the use of RegExp pattern produces original string All a's will be replaced
How to achieve expected result?
Related
This question already has answers here:
Get text between two rounded brackets
(7 answers)
Closed 2 years ago.
I have a string like Manila (Philippines) and want to replace it with only the substring Philippines. I tried using the following regex pattern, which works in Notepad++:
[^\(]+ \(([^\)]+)\)
However, I get an undefined result in JavaScript:
var x = "Manila (Philippines)";
console.log(x.replace(/[^\(]+ \(([^\)]+)\)/,$1));
You just forgot the " around your replace pattern!
console.log(x.replace(/[^\(]+ \(([^\)]+)\)/,"$1")); will work correctly!
You can use .match():
var x = "Manila (Philippines)";
var result = x.match(/\((.+)\)/).pop();
// regex for string contained in parentheses
console.log(result);
This question already has answers here:
Why do regex constructors need to be double escaped?
(5 answers)
Closed 4 years ago.
I have the following regular expression:
\d{4}(-\d{2}){2}
Which is supposed to match dates that follow the YYYY-MM-DD format, so 1990-01-01 should successfuly match. However this fails when I try it in javascript.
var x = new RegExp('\d{4}(-\d{2}){2}')
x.test('1990-02-01') //why is this false?
Use the regular js regex syntax. Like this:
var x = /\d{4}(-\d{2}){2}/;
console.log(x.test('1990-02-01'));
if you want to keep the new RegExp part, you have to escape the string's backslashes:
var x = new RegExp('\\d{4}(-\\d{2}){2}');
console.log(x.test('1990-02-01'));
This question already has answers here:
Regular Expression to find a string included between two characters while EXCLUDING the delimiters
(13 answers)
Closed 5 years ago.
var faxNum = $("#txt_faxnum").val();
//Value : ""kekurt kekt809" <(732) 588-8300>"
I want to split between "< >". Example: Just I need to this section : (732) 588-8300
How to split this string ?
You can try this
var String=faxNum.substring(str.lastIndexOf("<")+1,faxNum.lastIndexOf(">"));
This question already has answers here:
Remove characters from a string [duplicate]
(6 answers)
Closed 7 years ago.
I have the below variable in JavaScript. I want to remove the "comma" sign using jQuery /JavaScript.
var test = ",,2,4,,,3,,3,,,"
Expected output: var test = "2,4,3,3"
please advice
Use replace() with regex
var test = ",,2,4,,,3,,3,,,";
document.write(test.replace(/,+/g,',').replace(/^,|,$/g,''));
replace(/,+/g,',') - To remove multiple comma with one.
replace(/^,|,$/g,'') - To remove comma at starting and ending.
This question already has answers here:
How do you use a variable in a regular expression?
(27 answers)
Closed 9 years ago.
I know that str.replace(/x/g, "y")replaces all x's in the string but I want to do this
function name(str,replaceWhat,replaceTo){
str.replace(/replaceWhat/g,replaceTo);
}
How can i use a variable in the first argument?
The RegExp constructor takes a string and creates a regular expression out of it.
function name(str,replaceWhat,replaceTo){
var re = new RegExp(replaceWhat, 'g');
return str.replace(re,replaceTo);
}
If replaceWhat might contain characters that are special in regular expressions, you can do:
function name(str,replaceWhat,replaceTo){
replaceWhat = replaceWhat.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&');
var re = new RegExp(replaceWhat, 'g');
return str.replace(re,replaceTo);
}
See Is there a RegExp.escape function in Javascript?
The third parameter of flags below was removed from browsers a few years ago and this answer is no longer needed -- now replace works global without flags
Replace has an alternate form that takes 3 parameters and accepts a string:
function name(str,replaceWhat,replaceTo){
str.replace(replaceWhat,replaceTo,"g");
}
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace