Extract substring from string using javascript regular expressions

Question

I am new to regular expressions in Javascript.

The string looks something like

Password=6)8+Ea:4n+DMtJc:W+*0>(-Y517;Persist Security Info=False;User ID=AppleTurnover;Initial Catalog=ProductDB;Data Source=Sydney

and I am trying to extract from this just the bit

Password=6)8+Ea:4n+DMtJc:W+*0>(-Y517

from ths string.

So, I have:

string="`Password=6)8+Ea:4n+DMtJc:W+*0>(-Y517;Persist Security Info=False;User ID=AppleTurnover;Initial Catalog=ProductDB;Data Source=Sydney"
substring=string.match('/Password=(.*);/g');

It returns back the entire string again. What is going wrong here?

I am using this tool: regex101.com Helps a lot

lvil
– lvil

2015-12-03 07:26:50 +00:00
Commented Dec 3, 2015 at 7:26 — lvil
– lvil, Commented Dec 3, 2015 at 7:26
Thank you... Helped mate!!!

Prajwal
– Prajwal

2015-12-03 09:18:57 +00:00
Commented Dec 3, 2015 at 9:18 — Prajwal
– Prajwal, Commented Dec 3, 2015 at 9:18

Tushar · Accepted Answer · 2015-12-03 07:22:09Z

22

Regex should not be wrapped in quotes. Use [^;]+ to select anything until ;.

var password = string.match(/Password=([^;]+)/)[1];

string = "`Password=6)8+Ea:4n+DMtJc:W+*0>(-Y517;Persist Security Info=False;User ID=AppleTurnover;Initial Catalog=ProductDB;Data Source=Sydney";
var password = string.match(/Password=([^;]+)/)[1];

document.write(password);

Or lazy regex can also be used

/Password=(.*?);/g
             ^

var string = "`Password=6)8+Ea:4n+DMtJc:W+*0>(-Y517;Persist Security Info=False;User ID=AppleTurnover;Initial Catalog=ProductDB;Data Source=Sydney";
var password = string.match(/Password=(.*?);/g);
document.write(password);

answered Dec 3, 2015 at 7:22

Tushar

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Comments

Jeff Meatball Yang · Accepted Answer · 2015-12-03 07:37:06Z

2

It's useful to think of the underlying grammar / syntax:

string := 'Password=' password ';' ...

So you want to match the non-semicolon characters.

string="`Password=6)8+Ea:4n+DMtJc:W+*0>(-Y517;Persist Security Info=False;User ID=AppleTurnover;Initial Catalog=ProductDB;Data Source=Sydney"
/Password=([^;]+)/.exec(string)[0] // or [1] if you want just the password

answered Dec 3, 2015 at 7:37

Jeff Meatball Yang

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Comments

yoko · Accepted Answer · 2015-12-03 07:27:40Z

0

You could Simply try this /Password.*;/

So you start looking for a String with Password in the beginning, followed by whatever character, until you reach a ;.

By using the g at the end of your RegEx, you are setting it for global, so you are not only looking for the first ;, but for every one. This might have been the reason why yours did not work.

answered Dec 3, 2015 at 7:27

yoko

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Comments

Didier Aupest · Accepted Answer · 2015-12-03 07:49:33Z

0

Avoid using potential reserved words.

Your first regular expression worked, you just added useless quote around it. Removig it will works.

var myString = "`Password=6)8+Ea:4n+DMtJc:W+*0>(-Y517;Persist Security Info=False;User ID=AppleTurnover;Initial Catalog=ProductDB;Data Source=Sydney"
var mySubstring = myString.match(/Password=(.*);Persist /g); // Remove the ' around the regex
var thePassword = mySubstring[0].replace('Password=', '');
thePassword = thePassword.replace(';Persist ', '');

answered Dec 3, 2015 at 7:49

Didier Aupest

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