String starting with backslash hacks my regex [duplicate] - javascript

This question already has answers here:
How can I use backslashes (\) in a string?
(4 answers)
Closed 3 years ago.
My string should be in the IRC command format : "/add john".
So, i created this Regex :
var regex = /^\/add ([A-Za-z0-9]+)$/
var bool = regex.test('\/add user1');
alert(bool);
The problem is either I use /***/ or RegExp syntax, if I set a backslash at the beginning of my string (like in my example above), my alert pop up show "true" and I don't want that.
I code in Javascript


You can use String.raw to make sure that the backlash is not removed when testing your input:
var regex = /^\/add ([A-Za-z0-9]+)$/
var bool = regex.test(String.raw`\/add user1`);
alert(bool);
You can play with this code here: https://jsbin.com/ziqecux/25/edit?js

Related

Extract text from enclosing parentheses using JavaScript [duplicate]

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);

Why is this regex incorrect? [duplicate]

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'));

Python Regex to get string(extension) after special character [duplicate]

This question already has an answer here:
Extract until end of line after a special character: Python
(1 answer)
Closed 5 years ago.
I have a string want to get string after special character which is extension.
i tried and it is works fine in javascript but wasnt in python.. how to do that?
here is my JS snippet,
my_str_0 = ".exr[6,7]";
my_str_1 = "/home/mohideen/test_dir/Samp_8860-fg_paint_%04d.exr[6] 1-7";
my_str_2 = "/home/mohideen/test_dir/Samp_8860-fg_paint_%05d.png[1] 1-10";
my_str_3 = "/home/mohideen/test_dir/Samp_8860-fg_paint_%05d.jpg";
for (var i in [my_str_0, my_str_1, my_str_2, my_str_3]) {
var reg = /([^.]*)$/.exec(eval("my_str_"+i));
console.log(reg[0]);
}
here is my python regex link

Use MultiLine Flag.
See here in this link

How to use dynamic variable between regular expression [duplicate]

This question already has answers here:
How do you use a variable in a regular expression?
(27 answers)
Closed 6 years ago.
I have string which contains some date and some comma separated values like this
var a = "1,13,20160308,200500000012016,10,Pending,01-02-2016,1|#|1,13,20160418,200500000012016,10,Pending,08-03-2016,1|#|1,13,20160623,200500000012016,10,Pending,18-04-2016,1|#|1,13,20160803,200500000012016,10,Pending,23-06-2016,1|#|1,13,20160912,200500000012016,10,Pending,03-08-2016,1|#|1,13,20161022,200500000012016,10,Pending,12-09-2016,1|#|1,13,20161129,200500000012016,10,Pending,22-10-2016,1|#|1,13,20170110,200500000012016,10,Pending,29-11-2016,1|#|1,13,20170215,200500000012016,10,Pending,10-01-2017,1|#|15-02-2017 APPEARANCE"
regular expression: /(.)*?01-02-2016(.)*?\|\#\|/igm
By using this regular expression i can able to delete unnecessary part in string.
Now i want to change 03-08-3016 (date) dynamically. If i use
var date = "01-02-2016"
var reg = /(.)*?${date}(.)*?\|\#\|/igm;
If you pring reg in console.log you will get like this below
console.log(reg) ----> output: '/(.)?01-02-2016(.)?|#|/igm'
Expected Final output will delete upto 01-02-2016,1|#|

Use this.
var regex="(.)*?01-02-2016(.)*?\\|\\#\\|";
var rx=new RegExp(regex,"igm");
console.log(rx);
//Then when do you want to change,
regex=regex.replace("01-02-2016","03-02-2016");
rx=new RegExp(regex,"igm");
console.log(rx);
JavaScript have 2 methods to make a Regular Expression.
1. write it in slashes //
2. Make from string using new RexExp(string);
If you make it from string, you can give the constraint(" global, incase, etc.") as the second parameter as i did in the above.
and also you have to double escape (\) the escape characters.

Javascript regex in attribute [duplicate]

This question already has answers here:
Create RegExps on the fly using string variables
(6 answers)
Closed 8 years ago.
I need to use data attribute for regex just as
<div data-regex="REGEX-HERE">
and then get the value by javascript and put in a variable. and then do a test like
var regex = $(this).attr("data-regex");
regex.test(name)
when I tried to use "^[\x20-\x7E]+$" for testing english character is didn't work.
Note when I tried this
var regex = /^[\x20-\x7E]+$/;
It worked.
Thanks in advance

You can do this:
var regex = new RegExp("^[\x20-\x7E]+$",""); // Modifiers on the tend
So finally:
var regex = new RegExp($(this).data("regex"));
regex.test(name)

Categories

Resources