How can you make a specific pattern for a password?

Question

0.00/5 (No votes)

See more:

I don't really understand how patterns are made, I read something about RegEx, does that make codes for different patterns?

An example I didn't get was this:

Country code:

<input type="text" name="country_code" 
pattern="[A-Za-z]{3}" title="Three letter country code">
<input type="submit">

What I have tried:

I just didn't get the pattern part, I didn't get how that's the pattern for a three letter country code.

Posted 8-Mar-18 20:24pm

Member 13502831

Updated 8-Mar-18 20:45pm

v2

Add a Solution

Comments

Richard MacCutchan 9-Mar-18 3:03am

International country codes are only two letters.

Richard Deeming 9-Mar-18 8:59am

That depends on whether you're using ISO-3166-1 alpha 2[^] or ISO-3166 alpha 3[^]. :)

Richard MacCutchan 9-Mar-18 11:13am

The former is the de facto standard these days.

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Accepted Answer · 2018-03-08T20:46:00

Regexes can get pretty complex, but that one's simple:

[A-Za-z]{3}
[      ]       The square brackets say "any character in this set"
 A-Z           "Any uppercase character"
            or
    a-z        "Any lowercase character"
        { }    The curly brackets say "Repeat the previous item a specific number of times"
         3     "Exactly three times"

So the whole regex means "any three upper or lower case letters"

If you want to experiment with Regexes, get a copy of Expresso[^] - it's free, and it examines, explains, and generates Regular expressions.

There are also some very good whole books on Regeexs: regexes book - Google Search[^] which will explain teh detailed complexities a lot better than we can in a little text box!

But ... Regexes are a tool, and in the case they are a pattern matching tool. They have to be used in the right place, and that is for text matching operations - they are not good atr string evaluation. So if you want a password rule like "seven or more characters minimum" that's fine:

.{7,}

"Any character, at least seven of them".
But if your rule is "seven or more characters minimum, must include at least one upper case, one digit, and a special character" Then a regex is the wrong tool, because it's can't "count" and process the line, so teh regex becomes horribly complicated and impossible to maintain. Password rules should be coded in actual code, possibly using a number of regexes to gather the info: one for "how many upper case", one for "how many lower case", another for "how many digits", and a final one for "how many special characters". Those numbers then get used by the code to evaluate the rules.