Non repetive Alphanumeric 10 digit Char using LINQ

Question

I need to get non repetitive alphanumeric character in 10 digit using LINQ. I searched google a lot. But i could not able to find it out. Please help me to get the solution. Thanks

Please show us what you've tried, and where exactly you run into problems. — Frauke, Apr 11 '17 at 12:04
And I don't see how LINQ will help generating a pseudorandom string :-) — xanatos, Apr 11 '17 at 12:05
Sounds like what you really need is to use a stringbuilder and append characters mapped to a random number generator. — Mad Myche, Apr 11 '17 at 12:11
the first answer here generates a random string using linq, you just need to add some code to make the characters disctinct http://stackoverflow.com/questions/1344221/how-can-i-generate-random-alphanumeric-strings-in-c — Liviu Boboia, Apr 11 '17 at 12:12
I was trying in LINQ, thats why i mentioned like using LINQ. — Vetri, Apr 11 '17 at 12:13

Liviu Boboia · Accepted Answer · 2017-04-11T12:18:07.257

1

If you don't have to use linq

var chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
var stringChars = new char[10];
var random = new Random();

for (int i = 0; i < stringChars.Length; i++)
{
    var randomNumber = random.Next(chars.Length);
    stringChars[i] = chars[randomNumber];
    chars = chars.Replace(chars[randomNumber].ToString(), "");
}

var finalString = new String(stringChars);

edited Apr 11 '17 at 12:18

answered Apr 11 '17 at 12:15

Liviu Boboia

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You'll need an inner cycle to avoid all the `\0` you are adding to your `chars` string... and the `Replace` doesn't modify the original string (strings are immutable in .NET), so `chars = chars.Replace(` – xanatos Apr 11 '17 at 12:17
hacked it a bit by converting the char into a string, thanks – Liviu Boboia Apr 11 '17 at 12:20
Its awasome. Thank you so much – Vetri Apr 11 '17 at 12:30

score 0 · Answer 2 · answered Apr 11 '17 at 12:12

It is a very interesting LINQ question... Probably by using Aggregate it is solvable...

Mmmh... yes... it is evil enough:

var rnd = new Random();
var chars = "ABCDEFGHIJ0123456789";
var res = Enumerable.Range(0, 10)
    .Select(x => rnd.Next(0, chars.Length - x))
    .Aggregate(
        Tuple.Create(string.Empty, chars), 
        (prev, ix) => Tuple.Create(
            prev.Item1 + prev.Item2[ix], 
            prev.Item2.Substring(0, ix) + prev.Item2.Substring(ix + 1)
        )
    ).Item1;

In general using LINQ is wrong here, because every character depends on all the previous characters. This is complex to do in LINQ. I had to cheat heavily, using the .Aggregate() and keeping a "state" of all the unused characters (the Item2) and adding the characters for the "response" to the Item1.

Works:) Thank you for your valuable time :) – Vetri Apr 11 '17 at 12:31 — Vetri, Apr 11 '17 at 12:31

Non repetive Alphanumeric 10 digit Char using LINQ

2 Answers2