There is a library to generate Random numbers, so why isn't there a library for generation of random strings?
In other words how to generate a random string, and specify desired length, or better, generate unique string on specification you want i.e. specify the length, a unique string within my application is enough for me.
I know I can create a Guid (Globally Unique IDentifier) but those are quite long, longer they need to be.
int length = 8;
string s = RandomString.NextRandomString(length)
uniquestringCollection = new UniquestringsCollection(length)
string s2 = uniquestringCollection.GetNext();
There are many ways to generate a random, unique, alphanumeric string in PHP which are given below: Using str_shuffle() Function: The str_shuffle() function is an inbuilt function in PHP and is used to randomly shuffle all the characters of a string passed to the function as a parameter.
I can't recall where I got this, so if you know who originally authored this, please help me give attribution.
private static void Main()
{
const string AllowedChars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz#@$^*()";
Random rng = new Random();
foreach (string randomString in rng.NextStrings(AllowedChars, (15, 64), 25))
{
Console.WriteLine(randomString);
}
Console.ReadLine();
}
private static IEnumerable<string> NextStrings(
this Random rnd,
string allowedChars,
(int Min, int Max)length,
int count)
{
ISet<string> usedRandomStrings = new HashSet<string>();
(int min, int max) = length;
char[] chars = new char[max];
int setLength = allowedChars.Length;
while (count-- > 0)
{
int stringLength = rnd.Next(min, max + 1);
for (int i = 0; i < stringLength; ++i)
{
chars[i] = allowedChars[rnd.Next(setLength)];
}
string randomString = new string(chars, 0, stringLength);
if (usedRandomStrings.Add(randomString))
{
yield return randomString;
}
else
{
count++;
}
}
}
How about-
static Random rd = new Random();
internal static string CreateString(int stringLength)
{
const string allowedChars = "ABCDEFGHJKLMNOPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz0123456789!@$?_-";
char[] chars = new char[stringLength];
for (int i = 0; i < stringLength; i++)
{
chars[i] = allowedChars[rd.Next(0, allowedChars.Length)];
}
return new string(chars);
}
How about
string.Join("", Enumerable.Repeat(0, 100).Select(n => (char)new Random().Next(127)));
or
var rand = new Random();
string.Join("", Enumerable.Repeat(0, 100).Select(n => (char)rand.Next(127)));
This approach uses the minimum number of concatenated GUIDs to return a random string of the desired number of characters.
/// <summary>
/// Uses concatenated then SubStringed GUIDs to get a random string of the
/// desired length. Relies on the randomness of the GUID generation algorithm.
/// </summary>
/// <param name="stringLength">Length of string to return</param>
/// <returns>Random string of <paramref name="stringLength"/> characters</returns>
internal static string GetRandomString(int stringLength)
{
StringBuilder sb = new StringBuilder();
int numGuidsToConcat = (((stringLength - 1) / 32) + 1);
for(int i = 1; i <= numGuidsToConcat; i++)
{
sb.Append(Guid.NewGuid().ToString("N"));
}
return sb.ToString(0, stringLength);
}
Example output with a length of 8:
39877037
2f1461d8
152ece65
79778fc6
76f426d8
73a27a0d
8efd1210
4bc5b0d2
7b1aa10e
3a7a5b3a
77676839
abffa3c9
37fdbeb1
45736489
Example output with a length of 40 (note the repeated '4' - in a v4 GUID, thee is one hex digit that will always be a 4 (effectively removing 4 bits) -- the algorithm could be improved by removing the '4' to improve randomness, given that the returned length of the string can be less than the length of a GUID (32 chars)...):
e5af105b73924c3590e99d2820e3ae7a3086d0e3
e03542e1b0a44138a49965b1ee434e3efe8d063d
c182cecb5f5b4b85a255a397de1c8615a6d6eef5
676548dc532a4c96acbe01292f260a52abdc4703
43d6735ef36841cd9085e56f496ece7c87c8beb9
f537d7702b22418d8ee6476dcd5f4ff3b3547f11
93749400bd494bfab187ac0a662baaa2771ce39d
335ce3c0f742434a904bd4bcad53fc3c8783a9f9
f2dd06d176634c5b9d7083962e68d3277cb2a060
4c89143715d34742b5f1b7047e8107fd28781b39
2f060d86f7244ae8b3b419a6e659a84135ec2bf8
54d5477a78194600af55c376c2b0c8f55ded2ab6
746acb308acf46ca88303dfbf38c831da39dc66e
bdc98417074047a79636e567e4de60aa19e89710
a114d8883d58451da03dfff75796f73711821b02
C# Fiddler Demo: https://dotnetfiddle.net/Y1j6Dw
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