digit

I'm teaching myself regular expressions, and found a quizzing site that has been helping me find more applications for them and has been helping me expand my knowledge of how they work. I found a question asking me to form a regex to match 10 digit numbers that are multiples of 3s. The only way I can think of doing this is by having the regex recognise numbers' values and be able to manipulate them mathematically. How is this possible? In other words, what regex would match 0003 0006 0351 1749 but not match 0005 0011 0361 4372 First you need to start with the rule that a number is divisble by

I have string "ololo123". I need get position of first digit - 1. How to set mask of search ? Something like this should do the trick for you: Public Function GetPositionOfFirstNumericCharacter(ByVal s As String) As Integer For i = 1 To Len(s) Dim currentCharacter As String currentCharacter = Mid(s, i, 1) If IsNumeric(currentCharacter) = True Then GetPositionOfFirstNumericCharacter = i Exit Function End If Next i End Function You can then call it like this: Dim iPosition as Integer iPosition = GetPositionOfFirstNumericCharacter("ololo123") Here is a lightweight and fast method that avoids

I saw a question on a math forum a while back where a person was discussing adding up the digits in a number over and over again until a single digit is achieved. (i.e. "362" would become "3+6+2" which would become "11"... then "11" would become "1+1" would would become "2" therefor "362" would return 2... I wrote some nice code to get an answer to this and posted it only to be outdone by a user who suggested that any number in modulo 9 is equal to this "infinite digit sum", I checked it an he was right... well almost right, if zero was returned you had to switch it out with a "9" but that was

I'm searching for an algorithm for Digit summing. Let me outline the basic principle: Say you have a number: 18268 . 1 + 8 + 2 + 6 + 8 = 25 2 + 5 = 7 And 7 is our final number. It's basically adding each number of the whole number until we get down to a single (also known as a 'core') digit. It's often used by numerologists. I'm searching for an algorithm (doesn't have to be language in-specific) for this. I have searched Google for the last hour with terms such as digit sum algorithm and whatnot but got no suitable results. Because 10-1=9, a little number theory will tell you that the final

Determine whether an integer is a palindrome. Do this without extra space. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of converting the integer to string, note the restriction of using extra space. You could also try reversing an integer. However, if you have solved the problem "Reverse Integer", you know that the reversed integer might overflow. How would you handle such case? There is a more generic way of solving this problem. 思路1（不推荐）：利用Reverse Integer的方法，求的转换后的数字，然后比较是否相等。提示说这样有溢出的问题，想了想感觉问题不大，leetcode也过了。因为首先输入必须是一个合法的int值，负数直接返回false，对于正数