Converting string to sortable number

Is there any way of converting a string value (any content) to a number such that they both sort in the same way? I don't need to be able to convert the number back to a string. In fact it would be an advantage if it were impossible to convert it back.

I don't need to be able to sort any length of string. If a 64-bit long integer is used as the sort-value then I could trim the texts to a value that fits this number range.


I don't think there can be 100% correct way since sorting a string depends on the culture. For ex

int c1 = String.Compare("AA", "BB", false, CultureInfo.GetCultureInfo("en-US")); //return -1
int c2 = String.Compare("AA", "BB", false, CultureInfo.GetCultureInfo("da-DK")); //return  1

The closest thing I can think of is:

ulong l = BitConverter.ToUInt64(Encoding.UTF8.GetBytes(str), 0);

PS: pad str if its len is shorter than 8

You could take the first 8 bytes from the string, the 8 bytes would make up a ulong. It would only be 4 characters of the string with unicode, or 8 characters if you limit the strings to ASCII.

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