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Parse multiple values from string c#

Suppose I have written "5 and 6" or "5+6". How can I assign 5 and 6 to two different variables in c# ?
P.S. I also want to do certain work if certain chars are found in string. Suppose I have written 5+5. Will this code do that ?
if(string.Contains("+"))
{
sum=x+y;
}

string input="5+5";
var numbers = Regex.Matches(input, #"\d+")
.Cast<Match>()
.Select(m => m.Value)
.ToList();

Personally, I would vote against doing some splitting and regular expression stuff.
Instead I would (and did in the past) use one of the many Expression Evaluation libraries, like e.g. this one over at Code Project (and the updated version over at CodePlex).
Using the parser/tool above, you could do things like:
A simple expression evaluation then could look like:
Expression e = new Expression("5 + 6");
Debug.Assert(11 == e.Evaluate());
To me this is much more error-proof than doing the parsing all by myself, including regular expressions and the like.

You should use another name for your string than string
var numbers = yourString.Split("+");
var sum = Convert.ToInt32(numbers[0]) + Convert.ToInt32(numbers[1]);
Note: Thats an implementation without any error checking or error handling...

If you want to assign numbers from string to variables, you will have to parse string and make conversion.
Simple example, if you have text with only one number
string text = "500";
int num = int.Parse(text);
Now, if you want to parse something more complicated, you can use split() and/or regex to get all numbers and operators between them. Than you just iterate array and assign numbers to variables.
string text = "500+400";
if (text.Contains("+"))
{
String[] data = text.Split("+");
int a = int.Parse(data[0]);
int b = int.Parse(data[1]);
int res = a + b;
}
Basicly, if you have just 2 numbers and operazor between them, its ok. If you want to make "calculator" you will need something more, like Binary Trees or Stack.

Use the String.Split method. It splits your string rom the given character and returns a string array containing the value that is broken down into multiple pieces depending on the character to break, in this case, its "+".
int x = 0;
int y = 0;
int z = 0;
string value = "5+6";
if (value.Contains("+"))
{
string[] returnedArray = value.Split('+');
x = Convert.ToInt32(returnedArray[0]);
y = Convert.ToInt32(returnedArray[1]);
z = x + y;
}

Something like this may helpful
string strMy = "5&6";
char[] arr = strMy.ToCharArray();
List<int> list = new List<int>();
foreach (char item in arr)
{
int value;
if (int.TryParse(item.ToString(), out value))
{
list.Add(item);
}
}
list will contains all the integer values

You can use String.Split method like;
string s = "5 and 6";
string[] a = s.Split(new string[] { "and", "+" }, StringSplitOptions.RemoveEmptyEntries);
Console.WriteLine(a[0].Trim());
Console.WriteLine(a[1].Trim());
Here is a DEMO.

Use regex to get those value and then switch on the operand to do the calculation
string str = "51 + 6";
str = str.Replace(" ", "");
Regex regex = new Regex(#"(?<rightHand>\d+)(?<operand>\+|and)(?<leftHand>\d+)");
var match = regex.Match(str);
int rightHand = int.Parse(match.Groups["rightHand"].Value);
int leftHand = int.Parse(match.Groups["leftHand"].Value);
string op = match.Groups["operand"].Value;
switch (op)
{
case "+":
.
.
.
}

Split function maybe is comfortable in use but it is space inefficient
because it needs array of strings
Maybe Trim(), IndexOf(), Substring() can replace Split() function

Getting substring between two separators in an arbitrary position

I have following string:
string source = "Test/Company/Business/Department/Logs.tvs/v1";
The / character is the separator between various elements in the string. I need to get the last two elements of the string. I have following code for this purpose. This works fine. Is there any faster/simpler code for this?
CODE
static void Main()
{
string component = String.Empty;
string version = String.Empty;
string source = "Test/Company/Business/Department/Logs.tvs/v1";
if (!String.IsNullOrEmpty(source))
{
String[] partsOfSource = source.Split('/');
if (partsOfSource != null)
{
if (partsOfSource.Length > 2)
{
component = partsOfSource[partsOfSource.Length - 2];
}
if (partsOfSource.Length > 1)
{
version = partsOfSource[partsOfSource.Length - 1];
}
}
}
Console.WriteLine(component);
Console.WriteLine(version);
Console.Read();
}

Why no regular expression? This one is fairly easy:
.*/(?<component>.*)/(?<version>.*)$
You can even label your groups so for your match all you need to do is:
component = myMatch.Groups["component"];
version = myMatch.Groups["version"];

The following should be faster, as it only scans as much of the string as it needs to to find two / and it doesn't bother splitting up the whole string:
string component = "";
string version = "";
string source = "Test/Company/Business/Department/Logs.tvs/v1";
int last = source.LastIndexOf('/');
if (last != -1)
{
int penultimate = source.LastIndexOf('/', last - 1);
version = source.Substring(last + 1);
component = source.Substring(penultimate + 1, last - penultimate - 1);
}
That said, as with all performance questions: profile! Try the two side-by-side with a big list of real-life inputs and see which is fastest.
(Also, this will leave empty strings rather than throw an exception if there is no slash in the input... but throw if source is null, lazy me.)

Your approach is the most suitable one given that your are looking for substrings at a particular index. A LINQ expression to do the same in this case will likely not improve the code or its readability.
For reference, there is some great information from Microsoft here on working with strings and LINQ. In particular see the article here which covers some examples with both LINQ and RegEx.
EDIT: +1 For Matt's named group within RegEx approach... that's the nicest solution I've seen.

Your code mostly looks fine. A couple of points to note:
String.Split() will never return null, so you don't need the null check on it.
If the source string has fewer than two / characters, how would you deal with that? (The Original Post was updated to address this)
Do you really want to just output empty strings if your source string is null or empty (or invalid)? If you have specific expectations about the nature of the input, you may want to consider failing fast when those expectations are not met.

You could try something like this but I doubt it would be much faster. You could do some meassurements with System.Diagnostics.StopWatch to see if you feel the need.
string source = "Test/Company/Business/Department/Logs.tvs/v1";
int index1 = source.LastIndexOf('/');
string last = source.Substring(index1 + 1);
string substring = source.Substring(0, index1);
int index2 = substring.LastIndexOf('/');
string secondLast = substring.Substring(index2 + 1);

I would try
string source = "Test/Company/Business/Department/Logs.tvs/v1";
var components = source.Split('/').Reverse().Take(2);
String last = string.Empty;
var enumerable = components as string[] ?? components.ToArray();
if (enumerable.Count() == 2)
last = enumerable.FirstOrDefault();
var secondLast = enumerable.LastOrDefault();
Hope this will help

you can retrieve the last two words using the process as below:
string source = "Test/Company/Business/Department/Logs.tvs/v1";
String[] partsOfSource = source.Split('/');
if(partsOfSourch.length>2)
for(int i=partsOfSourch.length-2;i<=partsOfSource.length-1;i++)
console.writeline(partsOfSource[i]);

How to split a string with '#' in C#

I tried to split a string wich contains these character #
domicilioSeparado = domicilio.Split(#"#".ToCharArray());
but every time the array contains just one member. I've tried a lot of combinations but anything seems to work, I also tried to replace the string with a blank space and it kinda works - the problem is that it remains a single string.
domicilio = domicilio.Replace(#"#", #" ");
How can I resolve this?
Complete code:
String[] domicilioSeparado;
String domicilio = dbRow["DOMICILIO"].ToString();
domicilioSeparado = domicilio.Split(#"#".ToCharArray());
if (Regex.IsMatch(domicilioSeparado.Last(), #"\d"))
{
String domicilioSinNum = "";
domicilioSinNum = domicilioSeparado[0];
custTable.Rows.Add(counter, dbRow["CUENTA"], nombre,
paterno, materno, domicilioSinNum, domicilioSeparado.Last(), tipoEntidad);
}

If you just want to split a string on a delimiter, in this instance '#', then you can use this:
domicilioSeparado = domicilio.Split("#");
That should give you what you want. Your second attempt simply replaces all the characters '#' in the string with ' ', which doesn't seem to be what you want. Can we see the string you're trying to split? That might help explain why it's not working.
EDIT:
Ok, here's how I think your code should look, give this a shot and let me know how it goes.
List<string> domicilioSeparado = new List<string>();
String domicilio = dbRow["DOMICILIO"].ToString();
domicilioSeparado = domicilio.Split("#");
if (Regex.IsMatch(domicilioSeparado.Last(), #"\d"))
{
String domicilioSinNum = "";
domicilioSinNum = domicilioSeparado[0];
custTable.Rows.Add(counter, dbRow["CUENTA"], nombre,
paterno, materno, domicilioSinNum, domicilioSeparado.Last(), tipoEntidad);
}

Try this:
string[] domicilioSeparado;
domicilioSeparado = domicilio.Split('#');
Some notes:
1 - It is ('#'), instead of ("#"); 2 - Replace does not split a string, it only replace that part, keeping as a single string.
In case you want an example that includes the printing of the whole array:
string domicilio = "abc#def#ghi";
string[] domicilioSeparado;
domicilioSeparado = domicilio.Split('#');
for (int i = 0; i < domicilioSeparado.Length; i++)
{
MessageBox.Show(domicilioSeparado[i]);
}
It will open a Message Box for each element within domicilioSeparado.

How to remove a duplicate set of characters in a string

For example a string contains the following (the string is variable):
http://www.google.comhttp://www.google.com
What would be the most efficient way of removing the duplicate url here - e.g. output would be:
http://www.google.com

I assume that input contains only urls.
string input = "http://www.google.comhttp://www.google.com";
// this will get you distinct URLs but without "http://" at the beginning
IEnumerable<string> distinctAddresses = input
.Split(new[] {"http://"}, StringSplitOptions.RemoveEmptyEntries)
.Distinct();
StringBuilder output = new StringBuilder();
foreach (string distinctAddress in distinctAddresses)
{
// when building the output, insert "http://" before each address so
// that it resembles the original
output.Append("http://");
output.Append(distinctAddress);
}
Console.WriteLine(output);

Efficiency has various definitions: code size, total execution time, CPU usage, space usage, time to write the code, etc. If you want to be "efficient", you should know which one of these you're trying for.
I'd do something like this:
string url = "http://www.google.comhttp://www.google.com";
if (url.Length % 2 == 0)
{
string secondHalf = url.Substring(url.Length / 2);
if (url.StartsWith(secondHalf))
{
url = secondHalf;
}
}
Depending on the kinds of duplicates you need to remove, this may or may not work for you.

collect strings into list and use distinct, if your string has http address you can apply regex http:.+?(?=((http:)|($)) with RegexOptions.SingleLine
var distinctList = list.Distinct(StringComparer.CurrentCultureIgnoreCase).ToList();

Given you don't know the length of the string, you don't know if something is double and you don't know what is double:
string yourprimarystring = "http://www.google.comhttp://www.google.com";
int firstCharacter;
string temp;
for(int i = 0; i <= yourprimarystring.length; i++)
{
for(int j = 0; j <= yourprimarystring.length; j++)
{
string search = yourprimarystring.substring(i,j);
firstCharacter = yourprimaryString.IndexOf(search);
if(firstCharacter != -1)
{
temp = yourprimarystring.substring(0,firstCharacter) + yourprimarystring.substring(firstCharacter + j - i,yourprimarystring.length)
yourprimarystring = temp;
}
}
This itterates through all your elements, takes all out from first to last letter and searches for them like this:
ABCDA - searches for A finds A exludes A, thats the problem, you need to specify how long the duplication needs to be if you want to make it variable, but maybe my code helps you.

How can I read input as two different answers

Say I get the following question
Console.WriteLine("Which teams have faced eachother? - use Red vs Blue format");
Then my answer to the question above will have two teams. But how can read them as two seperate?
So that i only read [Red] [Blue], but the "vs" part inbetween as to be there.
I hope my you understood what I am trying to say. My english is not great.
best regards,
ps, as you can tell I am pretty new in programming.
edit: oh and this is all in C#

You can use String.Split():
var answers = userInput.Split(new String[] { "vs" }, StringSplitOptions.RemoveEmptyEntries);
if (answers.Length == 2) {
var red = answers[0];
var blue = answers[1];
}

There are many option you can use Split function to make it array and remove "vs"
or simple use String.Replace("vs","") function to replace the "vs" string with blank value.

You can try using a regular expression:
Match m = Regex.Match("^(?<team1>\.+) vs (?<team2>\.+)$", userInput);
if (m.Success)
{
string team1 = m.Groups["team1"].Value;
string team2 = m.Groups["team2"].Value;
}
Please note that this may not be 100% syntactically correct - you have to refer to IntelliSense a bit - for example, I'm not sure whether the pattern is the first or the second parameter in Match, but I'm sure you get the picture.

U can read all as one string then split with "vs" seperator, then ull get table of 2 strings that u need

Use the String.Split function, as others have suggested. This will split your string into an array of strings. Then, identify which string in the array is the 'vs' string. Take the value of the index prior to 'vs' and after 'vs'. For example:
string input = "Which teams have faced eachother? - use Red vs Blue format";
string[] inputArray = input.Split( ' ' );
int vsLocation = 0;
for ( int i = 0; i < inputArray.Length; i++ ) {
if ( inputArray[i] == "vs" ) {
vsLocation = i;
break;
}
}
if ( vsLocation > 0) {
string team1 = inputArray[vsLocation - 1];
string team2 = inputArray[vsLocation + 1];
}