C# Regex for masking E-Mails - c#

Is there a simple way for masking E-Mail addresses using Regular Expressions in C#?
My E-Mail:
myawesomeuser#there.com
My goal:
**awesome****#there.com (when 'awesome' was part of the pattern)
So it's more like an inverted replacement where evertyhing that does not actually match will be replaced with *.
Note: The domain should never be replaced!
From a performance side of view, would it make more sense to split by the # and only check the first part then put it back together afterwards?
Note: I don't want to check if the E-Mail is valid or not. It's just a simple inverted replacement and only for my current needs, the string is an E-Mail but for sure it can be any other string as well.
Solution
After reading the comments I ended up with an extension-method for strings which perfectly matches my needs.
public static string MaskEmail(this string eMail, string pattern)
{
var ix1 = eMail.IndexOf(pattern, StringComparison.Ordinal);
var ix2 = eMail.IndexOf('#');
// Corner case no-#
if (ix2 == -1)
{
ix2 = eMail.Length;
}
string result;
if (ix1 != -1 && ix1 < ix2)
{
result = new string('*', ix1) + pattern + new string('*', ix2 - ix1 - pattern.Length) + eMail.Substring(ix2);
}
else
{
// corner case no str found, all the pre-# is replaced
result = new string('*', ix2) + eMail.Substring(ix2);
}
return result;
}
which then can be called
string eMail = myawesomeuser#there.com;
string maskedMail = eMail.MaskEmail("awesome"); // **awesome****#there.com

string email = "myawesomeuser#there.com";
string str = "awesome";
string rx = "^((?!" + Regex.Escape(str) + "|#).)*|(?<!#.*)(?<=" + Regex.Escape(str) + ")((?!#).)*";
string email2 = Regex.Replace(email, rx, x => {
return new string('*', x.Length);
});
There are two sub-regular expressions here:
^((?!" + Regex.Escape(str) + "|#).)*
and
(?<!#.*)(?<=" + Regex.Escape(str) + ")((?!#).)*
They are in | (or)
The first one means: from the start of the string, any character but stop when you find str (escaped) or #
The second one means: there mustn't be a # before the start of this matching and, starting from str (escaped), replace any character stopping at the #
Probably faster/easier to read:
string email = "myawesomeuser#there.com";
string str = "awesome";
int ix1 = email.IndexOf(str);
int ix2 = email.IndexOf('#');
// Corner case no-#
if (ix2 == -1) {
ix2 = email.Length;
}
string email3;
if (ix1 != -1 && ix1 < ix2) {
email3 = new string('*', ix1) + str + new string('*', ix2 - ix1 - str.Length) + email.Substring(ix2);
} else {
// corner case no str found, all the pre-# is replaced
email3 = new string('*', ix2) + email.Substring(ix2);
}
This second version is better because it handle corner cases like: string not found and no domain in the email.

(awesome)|.(?=.*#)
Try this.Replace by *$1.But there will be an extra * at the start.So remove a * from the masked email from the start.See demo.
https://regex101.com/r/wU7sQ0/29

Non RE;
string name = "awesome";
int pat = email.IndexOf('#');
int pname = email.IndexOf(name);
if (pname < pat)
email = new String('*', pat - name.Length).Insert(pname, name) + email.Substring(pat);

Related

Remove text between quotes

I have a program, in which you can input a string. But I want text between quotes " " to be removed.
Example:
in: Today is a very "nice" and hot day.
out: Today is a very "" and hot day.
Console.WriteLine("Enter text: ");
text = Console.ReadLine();
int letter;
string s = null;
string s2 = null;
for (s = 0; s < text.Length; letter++)
{
if (text[letter] != '"')
{
s = s + text[letter];
}
else if (text[letter] == '"')
{
s2 = s2 + letter;
letter++;
(text[letter] != '"')
{
s2 = s2 + letter;
letter++;
}
}
}
I don't know how to write the string without text between quotes to the console.
I am not allowed to use a complex method like regex.
This should do the trick. It checks every character in the string for quotes.
If it finds quotes then sets a quotesOpened flag as true, so it will ignore any subsequent character.
When it encounters another quotes, it sets the flag to false, so it will resume copying the characters.
Console.WriteLine("Enter text: ");
text = Console.ReadLine();
int letterIndex;
string s2 = "";
bool quotesOpened = false;
for (letterIndex= 0; letterIndex< text.Length; letterIndex++)
{
if (text[letterIndex] == '"')
{
quotesOpened = !quotesOpened;
s2 = s2 + text[letterIndex];
}
else
{
if (!quotesOpened)
s2 = s2 + text[letterIndex];
}
}
Hope this helps!
A take without regular expressions, which I like better, but okay:
string input = "abc\"def\"ghi";
string output = input;
int firstQuoteIndex = input.IndexOf("\"");
if (firstQuoteIndex >= 0)
{
int secondQuoteIndex = input.IndexOf("\"", firstQuoteIndex + 1);
if (secondQuoteIndex >= 0)
{
output = input.Substring(0, firstQuoteIndex + 1) + input.Substring(secondQuoteIndex);
}
}
Console.WriteLine(output);
What it does:
It searches for the first occurrence of "
Then it searches for the second occurrence of "
Then it takes the first part, including the first " and the second part, including the second "
You could improve this yourself by searching until the end of the string and replace all occurrences. You have to remember the new 'first index' you have to search on.
string text = #" Today is a very ""nice"" and hot day. Second sentense with ""text"" test";
Regex r = new Regex("\"([^\"]*)\"");
var a = r.Replace(text,string.Empty);
Please try this.
First we need to split string and then remove odd items:
private static String Remove(String s)
{
var rs = s.Split(new[] { '"' }).ToList();
return String.Join("\"\"", rs.Where(_ => rs.IndexOf(_) % 2 == 0));
}
static void Main(string[] args)
{
var test = Remove("hello\"world\"\"yeah\" test \"fhfh\"");
return;
}
This would be a possible solution:
String cmd = "This is a \"Test\".";
// This is a "".
String newCmd = cmd.Split('\"')[0] + "\"\"" + cmd.Split('\"')[2];
Console.WriteLine(newCmd);
Console.Read();
You simply split the text at " and then add both parts together and add the old ". Not a very nice solution, but it works anyway.
€dit:
cmd[0] = "This is a "
cmd[1] = "Test"
cmd[2] = "."
You can do it like this:
Console.WriteLine("Enter text: ");
var text = Console.ReadLine();
var skipping = false;
var result = string.Empty;
foreach (var c in text)
{
if (!skipping || c == '"') result += c;
if (c == '"') skipping = !skipping;
}
Console.WriteLine(result);
Console.ReadLine();
The result string is created by adding characters from the original string as long we are not between quotes (using the skipping variable).
Take all indexes of quotes remove the text between quotes using substring.
static void Main(string[] args)
{
string text = #" Today is a very ""nice"" and hot day. Second sentense with ""text"" test";
var foundIndexes = new List<int>();
foundIndexes.Add(0);
for (int i = 0; i < text.Length; i++)
{
if (text[i] == '"')
foundIndexes.Add(i);
}
string result = "";
for(int i =0; i<foundIndexes.Count; i+=2)
{
int length = 0;
if(i == foundIndexes.Count - 1)
{
length = text.Length - foundIndexes[i];
}
else
{
length = foundIndexes[i + 1] - foundIndexes[i]+1;
}
result += text.Substring(foundIndexes[i], length);
}
Console.WriteLine(result);
Console.ReadKey();
}
Output: Today is a very "" and hot day. Second sentense with "" test";
Here dotNetFiddle

Capturing a number within curly brackets inside a string c#

I have posted this again as my previous post was admittedly rather ambiguous..sorry!!
I have a string and I want to capture the number inside it and then add one to it!.
For example I have an email subject header saying "Re: Hello (1)"
I want to capture that 1 and then raise it by 2, then 3,then 4,etc. The difficulty I am having is taking into consideration the growing numbers, once it becomes say 10 or 100, that extra digit kills my current Regex expression.
Any help would be praised as always!
int replyno;
string Subject = "Re: Hey :) (1)";
if (Subject.Contains("Re:"))
{
try
{
replyno = int.Parse(Regex.Match(Subject, #"\(\d+\)").Value);
replyno++;
Subject = Subject.Remove(Subject.Length - 3);
TextBoxSubject.Text = Subject + "("+replyno+")";
}
catch
{
TextBoxSubject.Text = Subject + " (1)";
}
}
else
{
TextBoxSubject.Text = "Re: " + Subject;
}
Current output from this code fails from the Int.TryParse
Try substituting this code:
var m = Regex.Match(Subject, #"\((\d+)\)");
replyno = int.Parse(m.Groups[1].Value);
The changes are:
capture just the digits in the regex
parse just the captured digits
I'd also recommend that you check m.Success instead of just catching the resulting exception.
The problem is with the way you remove and replace the reply no.
Change your code this way
int replyno;
string Subject = "Re: Hey :) (1)";
if (Subject.Contains("Re:"))
{
try
{
replyno = int.Parse(Regex.Match(Subject, #"(\d+)").Value);
replyno++;
Subject = Regex.Replace(Subject,#"(\d+)", replyno.ToString());
TextBoxSubject.Text = Subject ;
}
catch
{
TextBoxSubject.Text = Subject + " (1)";
}
}
else
{
TextBoxSubject.Text = "Re: " + Subject;
}
I don't normally deal with regex so here's how i'd do it.
string subject = "Hello (1)";
string newSubject = string.Empty;
for (int j = 0; j < subject.Length; j++)
if (char.IsNumber(subject[j]))
newSubject += subject[j];
int number = 0;
int.TryParse(newSubject, out number);
subject = subject.Replace(number.ToString(), (++number).ToString());
You don't necessarily need regex for this, but you can adjust yours to \((?<number>\d+)\)$ to fix the problem.
For a regex solution, you can access the match using a group:
for (int i = 0; i < 10; i++)
{
int currentLevel = 0;
var regex = new System.Text.RegularExpressions.Regex(#"\((?<number>\d+)\)$");
var m = regex.Match(inputText);
string strLeft = inputText + " (", strRight = ")";
if (m.Success)
{
var levelText = m.Groups["number"];
if (int.TryParse(levelText.Value, out currentLevel))
{
var numCap = levelText.Captures[0];
strLeft = inputText.Substring(0, numCap.Index);
strRight = inputText.Substring(numCap.Index + numCap.Length);
}
}
inputText = strLeft + (++currentLevel).ToString() + strRight;
output.AppendLine(inputText);
}
Instead, consider just using IndexOf and Substring:
// Example
var inputText = "Subject Line";
for (int i = 0; i < 10; i++)
{
int currentLevel = 0;
int trimStart = inputText.Length;
// find the current level from the string
{
int parenStart = 0;
if (inputText.EndsWith(")")
&& (parenStart = inputText.LastIndexOf('(')) > 0)
{
int numStrLen = inputText.Length - parenStart - 2;
if (numStrLen > 0)
{
var numberText = inputText.Substring(parenStart + 1, numStrLen);
if (int.TryParse(numberText, out currentLevel))
{
// we found a number, remove it
trimStart = parenStart;
}
}
}
}
// add new number
{
// remove existing
inputText = inputText.Substring(0, trimStart);
// increment and add new
inputText = string.Format("{0} ({1})", inputText, ++currentLevel);
}
Console.WriteLine(inputText);
}
Produces
Subject Line
Subject Line (1)
Subject Line (2)
Subject Line (3)
Subject Line (4)
Subject Line (5)
Subject Line (6)
Subject Line (7)
Subject Line (8)
Subject Line (9)
Subject Line (10)

Replacing character after single quote

I am using the following C# code to modify a lowercase letter to uppercase after a single quote:
public virtual string FirstName
{
get { return _firstName; }
set
{
if (value != null)
{
int pos = value.IndexOf("'", 0);
int strlength = value.Length - 1;
if (pos >= 0 && pos != strlength)
{
string temp = value[pos + 1].ToString();
temp = temp.ToUpper();
value = value.Remove(pos + 1, 1);
value = value.Insert(pos + 1, temp);
}
}
}
}
To me this looks like overkill. Is there an easier way to achieve the desired result:
Value: Mc'donald
Expected: Mc'Donald
here is without regex
int pos = data.IndexOf("'");
if (pos >= 0 && pos < data.Length - 1)
{
StringBuilder sbl = new StringBuilder(data);
sbl[pos + 1] = char.ToUpper(sbl[pos + 1]);
data = sbl.ToString();
}
Since you're open to Regex, would this overload of the Regex.Replace do what you need?
Regex.Replace Method (String, MatchEvaluator)
Here's a modified version of the example given at the link above. I've changed it to use the '\w pattern and to return the match in upper case.
using System;
using System.Text.RegularExpressions;
class RegExSample
{
static string CapText(Match m)
{
// Return the match in upper case
return m.ToString().ToUpperInvariant();
}
static void Main()
{
string text = "Mc'donald";
System.Console.WriteLine("text=[" + text + "]");
Regex rx = new Regex(#"'\w");
string result = rx.Replace(text, new MatchEvaluator(RegExSample.CapText));
System.Console.WriteLine("result=[" + result + "]");
}
}
Perhaps regular expressions?
string value = "Mc'donald";
string found = Regex.Match(value, "'[\\w]").Value;
string result = value.Replace(found, found.ToUpper());
Console.WriteLine(result); // Mc'Donald

How can I search through a string in C# and replace areas bounded by a pattern?

We tried a few solutions now that try and use XML parsers. All fail because the strings are not always 100% valid XML. Here's our problem.
We have strings that look like this:
var a = "this is a testxxx of my data yxxx and of these xxx parts yxxx";
var b = "hello testxxx world yxxx ";
"this is a testxxx3yxxx and of these xxx1yxxx";
"hello testxxx1yxxx ";
The key here is that we want to do something to the data between xxx and yxxx. In the example above I would need a function that counts words and replaces the strings with a word count.
Is there a way we can process the string a and apply a function to change the data that's between the xxx and yxxx? Any function right now as we're just trying to get an idea of how to code this.
You can use Split method:
var parts = a.Split(new[] {"xxx", "yxxx"}, StringSplitOptions.None)
.Select((s, index) =>
{
string s1 = index%2 == 1 ? string.Format("{0}{2}{1}", "xxx", "yxxx", s + "1") : s;
return s1;
});
var result = string.Join("", parts);
If it always going to xxx and yxxx, you can use regex as suggested.
var stringBuilder = new StringBuilder();
Regex regex = new Regex("xxx(.*?)yxxx");
var splitGroups = Regex.Match(a);
foreach(var group in splitGroups)
{
var value = splitGroupsCopy[i];
// do something to value and then append it to string builder
stringBuilder.Append(string.Format("{0}{1}{2}", "xxx", value, "yxxx"));
}
I suppose this is as basic as it gets.
Using Regex.Replace will replace all the matches with your choice of text, something like this:
Regex rgx = new Regex("xxx.+yxxx");
string cleaned = rgx.Replace(a, "replacementtext");
This code will process each of the parts delimited by "xxx". It preserves the "xxx" separators. If you do not want to preserve the "xxx" separators, remove the two lines that say "result.Append(separator);".
Given:
"this is a testxxx of my data yxxx and there are many of these xxx parts yxxx"
It prints:
"this is a testxxx>> of my data y<<xxx and there are many of these xxx>> parts y<<xxx"
I'm assuming that's the kind of thing you want. Add your own processing to "processPart()".
using System;
using System.Text;
namespace ConsoleApplication1
{
internal class Program
{
private static void Main(string[] args)
{
string text = "this is a testxxx of my data yxxx and there are many of these xxx parts yxxx";
string separator = "xxx";
var result = new StringBuilder();
int index = 0;
while (true)
{
int start = text.IndexOf(separator, index);
if (start < 0)
{
result.Append(text.Substring(index));
break;
}
result.Append(text.Substring(index, start - index));
int end = text.IndexOf(separator, start + separator.Length);
if (end < 0)
{
throw new InvalidOperationException("Unbalanced separators.");
}
start += separator.Length;
result.Append(separator);
result.Append(processPart(text.Substring(start, end-start)));
result.Append(separator);
index = end + separator.Length;
}
Console.WriteLine(result);
}
private static string processPart(string part)
{
return ">>" + part + "<<";
}
}
}
[EDIT] Here's the code amended to work with two different separators:
using System;
using System.Text;
namespace ConsoleApplication1
{
internal class Program
{
private static void Main(string[] args)
{
string text = "this is a test<pre> of my data y</pre> and there are many of these <pre> parts y</pre>";
string separator1 = "<pre>";
string separator2 = "</pre>";
var result = new StringBuilder();
int index = 0;
while (true)
{
int start = text.IndexOf(separator1, index);
if (start < 0)
{
result.Append(text.Substring(index));
break;
}
result.Append(text.Substring(index, start - index));
int end = text.IndexOf(separator2, start + separator1.Length);
if (end < 0)
{
throw new InvalidOperationException("Unbalanced separators.");
}
start += separator1.Length;
result.Append(separator1);
result.Append(processPart(text.Substring(start, end-start)));
result.Append(separator2);
index = end + separator2.Length;
}
Console.WriteLine(result);
}
private static string processPart(string part)
{
return "|" + part + "|";
}
}
}
The indexOf() function will return to you the index of the first occurrence of a given substring.
(My indices might be a bit off, but) I would suggest doing something like this:
var searchme = "this is a testxxx of my data yxxx and there are many of these xxx parts yxxx";
var startindex= searchme.indexOf("xxx");
var endindex = searchme.indexOf("yxxx") + 3; //added 3 to find the index of the last 'x' instead of the index of the 'y' character
var stringpiece = searchme.substring(startindex, endindex - startindex);
and you can repeat that while startindex != -1
Like I said, the indices might be slightly off, you might have to add a +1 or -1 somewhere, but this will get you along nicely (I think).
Here is a little sample program that counts chars instead of words. But you should just need to change the processor function.
var a = "this is a testxxx of my data yxxx and there are many of these xxx parts yxxx";
a = ProcessString(a, CountChars);
string CountChars(string a)
{
return a.Length.ToString();
}
string ProcessString(string a, Func<string, string> processor)
{
int idx_start, idx_end = -4;
while ((idx_start = a.IndexOf("xxx", idx_end + 4)) >= 0)
{
idx_end = a.IndexOf("yxxx", idx_start + 3);
if (idx_end < 0)
break;
var string_in_between = a.Substring(idx_start + 3, idx_end - idx_start - 3);
var newString = processor(string_in_between);
a = a.Substring(0, idx_start + 3) + newString + a.Substring(idx_end, a.Length - idx_end);
idx_end -= string_in_between.Length - newString.Length;
}
return a;
}
I would use Regex Groups:
Here my solution to get the parts in the string:
private static IEnumerable<string> GetParts( string searchFor, string begin, string end ) {
string exp = string.Format("({0}(?<searchedPart>.+?){1})+", begin, end);
Regex regex = new Regex(exp);
MatchCollection matchCollection = regex.Matches(searchFor);
foreach (Match match in matchCollection) {
Group #group = match.Groups["searchedPart"];
yield return #group.ToString();
}
}
you can use it like to get the parts:
string a = "this is a testxxx of my data yxxx and there are many of these xxx parts yxxx";
IEnumerable<string> parts = GetParts(a, "xxx", "yxxx");
To replace the parts in the original String you can use the Regex Group to determine Length and StartPosition (#group.Index, #group.Length).

How to make a first letter capital in C#

How can the first letter in a text be set to capital?
Example:
it is a text. = It is a text.
public static string ToUpperFirstLetter(this string source)
{
if (string.IsNullOrEmpty(source))
return string.Empty;
// convert to char array of the string
char[] letters = source.ToCharArray();
// upper case the first char
letters[0] = char.ToUpper(letters[0]);
// return the array made of the new char array
return new string(letters);
}
It'll be something like this:
// precondition: before must not be an empty string
String after = before.Substring(0, 1).ToUpper() + before.Substring(1);
polygenelubricants' answer is fine for most cases, but you potentially need to think about cultural issues. Do you want this capitalized in a culture-invariant way, in the current culture, or a specific culture? It can make a big difference in Turkey, for example. So you may want to consider:
CultureInfo culture = ...;
text = char.ToUpper(text[0], culture) + text.Substring(1);
or if you prefer methods on String:
CultureInfo culture = ...;
text = text.Substring(0, 1).ToUpper(culture) + text.Substring(1);
where culture might be CultureInfo.InvariantCulture, or the current culture etc.
For more on this problem, see the Turkey Test.
If you are using C# then try this code:
Microsoft.VisualBasic.StrConv(sourceString, Microsoft.VisualBasic.vbProperCase)
I use this variant:
private string FirstLetterCapital(string str)
{
return Char.ToUpper(str[0]) + str.Remove(0, 1);
}
If you are sure that str variable is valid (never an empty-string or null), try:
str = Char.ToUpper(str[0]) + str[1..];
Unlike the other solutions that use Substring, this one does not do additional string allocations. This example basically concatenates char with ReadOnlySpan<char>.
I realize this is an old post, but I recently had this problem and solved it with the following method.
private string capSentences(string str)
{
string s = "";
if (str[str.Length - 1] == '.')
str = str.Remove(str.Length - 1, 1);
char[] delim = { '.' };
string[] tokens = str.Split(delim);
for (int i = 0; i < tokens.Length; i++)
{
tokens[i] = tokens[i].Trim();
tokens[i] = char.ToUpper(tokens[i][0]) + tokens[i].Substring(1);
s += tokens[i] + ". ";
}
return s;
}
In the sample below clicking on the button executes this simple code outBox.Text = capSentences(inBox.Text.Trim()); which pulls the text from the upper box and puts it in the lower box after the above method runs on it.
Take the first letter out of the word and then extract it to the other string.
strFirstLetter = strWord.Substring(0, 1).ToUpper();
strFullWord = strFirstLetter + strWord.Substring(1);
text = new String(
new [] { char.ToUpper(text.First()) }
.Concat(text.Skip(1))
.ToArray()
);
this functions makes capital the first letter of all words in a string
public static string FormatSentence(string source)
{
var words = source.Split(' ').Select(t => t.ToCharArray()).ToList();
words.ForEach(t =>
{
for (int i = 0; i < t.Length; i++)
{
t[i] = i.Equals(0) ? char.ToUpper(t[i]) : char.ToLower(t[i]);
}
});
return string.Join(" ", words.Select(t => new string(t)));;
}
string str = "it is a text";
// first use the .Trim() method to get rid of all the unnecessary space at the begining and the end for exemple (" This string ".Trim() is gonna output "This string").
str = str.Trim();
char theFirstLetter = str[0]; // this line is to take the first letter of the string at index 0.
theFirstLetter.ToUpper(); // .ToTupper() methode to uppercase the firstletter.
str = theFirstLetter + str.substring(1); // we add the first letter that we uppercased and add the rest of the string by using the str.substring(1) (str.substring(1) to skip the first letter at index 0 and only print the letters from the index 1 to the last index.)
Console.WriteLine(str); // now it should output "It is a text"
static String UppercaseWords(String BadName)
{
String FullName = "";
if (BadName != null)
{
String[] FullBadName = BadName.Split(' ');
foreach (string Name in FullBadName)
{
String SmallName = "";
if (Name.Length > 1)
{
SmallName = char.ToUpper(Name[0]) + Name.Substring(1).ToLower();
}
else
{
SmallName = Name.ToUpper();
}
FullName = FullName + " " + SmallName;
}
}
FullName = FullName.Trim();
FullName = FullName.TrimEnd();
FullName = FullName.TrimStart();
return FullName;
}
string Input = " it is my text";
Input = Input.TrimStart();
//Create a char array
char[] Letters = Input.ToCharArray();
//Make first letter a capital one
string First = char.ToUpper(Letters[0]).ToString();
//Concatenate
string Output = string.Concat(First,Input.Substring(1));
Try this code snippet:
char nm[] = "this is a test";
if(char.IsLower(nm[0])) nm[0] = char.ToUpper(nm[0]);
//print result: This is a test

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