Develop Reference

Split string at particular characters (C#)

What I want to do is to split an array and then put the character which i split at into another element
i.e. string text = "1*5+89-43&99" should become string[] textsplit = ["1","*","5","+","89","-","43","&","99"] (it must be a string)
and I will supply the characters to be left in seperate elements

You can do this using string.IndexOfAny.
Simply keep looking for the next index of any of the separators. When you find a separator, add the text between it and the last separator to your results, then look for the next separator.
string input = "1*1*5+89-43&33";
var separators = new[] { '+', '-', '*', '/', '&' };
var result = new List<string>();
int index;
int lastIndex = 0;
while ((index = input.IndexOfAny(separators, lastIndex)) != -1)
{
// Add the text before the separator, if there is any
if (index - lastIndex > 0)
{
result.Add(input.Substring(lastIndex, index - lastIndex));
}
// Add the separator itself
result.Add(input[index].ToString());
lastIndex = index + 1;
}
// Add any text after the last separator
if (lastIndex < input.Length)
{
result.Add(input.Substring(lastIndex));
}

Try with the following code snippet:
string text = "1*1*5+89-43&33";
List<string> textsplit = new List<string>();
foreach(var match in Regex.Matches(text, #"([*+/\-)(])|([0-9]+)"))
{
textsplit.Add(match.ToString());
}
Result added as an image.

Here's a basic and naive implementation that I beliewe will do what you want:
public static List<string> SplitExpression(string expression)
{
var parts = new List<string>();
bool isNumber(char c) => c == '.' || (c >= '0' && c <= '9');
bool isOperator(char c) => !isNumber(c);
int index = 0;
while (index < expression.Length)
{
char c = expression[index];
index++;
if (isNumber(c))
{
int numberIndex = index - 1;
while (index < expression.Length && isNumber(expression[index]))
index++;
parts.Add(expression.Substring(numberIndex, index - numberIndex));
}
else
parts.Add(c.ToString());
}
// move unary signs into following number
index = 0;
while (index < parts.Count - 1)
{
bool isSign = parts[index] == "-" || parts[index] == "+";
bool isFirstOrFollowingOperator = index == 0 || isOperator(parts[index - 1][0]);
bool isPriorToNumber = isNumber(parts[index + 1][0]);
if (isSign && isFirstOrFollowingOperator && isPriorToNumber)
{
parts[index + 1] = parts[index] + parts[index + 1];
parts.RemoveAt(index);
}
else
index++;
}
return parts;
}
Example input: "-1+-2*-10.1*.1", and output:
-1
+
-2
*
-10.1
*
.1

How can I get the values new.TITLE['kinds.of'].food

I am new to regex. I have this string
new.TITLE['kinds.of'].food
or
new.TITLE['deep thought'].food
I want to retrieve these tokens:
new, TITLE, kinds.of, food.
or (2nd example)
new, TITLE, deep thought, food.
I can't simply split it with '.' I need regex match to get the values.
How is it done?

When working with tokens a parser (FST - Finite State Machine in this case) should do:
private static IEnumerable<string> ParseIt(string value) {
int lastIndex = 0;
bool inApostroph = false;
for (int i = 0; i < value.Length; ++i) {
char ch = value[i];
if (ch == '\'') {
inApostroph = !inApostroph;
continue;
}
if (inApostroph)
continue;
if (ch == '.' || ch == ']' || ch == '[') {
if (i - lastIndex > 0) {
if (value[lastIndex] != '\'')
yield return value.Substring(lastIndex, i - lastIndex);
else {
string result = value.Substring(lastIndex, i - lastIndex).Replace("''", "'");
yield return result.Substring(1, result.Length - 2);
}
}
lastIndex = i + 1;
}
}
if (lastIndex < value.Length)
yield return value.Substring(lastIndex);
}
Tests:
string test1 = #"new.TITLE['kinds.of'].food";
string test2 = #"new.TITLE['deep thought'].food";
string[] result1 = ParseIt(test1).ToArray();
string[] result2 = ParseIt(test2).ToArray();
Console.WriteLine(string.Join(Environment.NewLine, result1));
Console.WriteLine(string.Join(Environment.NewLine, result2));
Outcome:
new
TITLE
kinds.of
food
new
TITLE
deep thought
food

How to make an incremental dynamic code that contains alphabets and numerics

My initial code is 'A0AA' and I need a code/function in C# that will increment it until it goes to 'Z9ZZ'.
for example.
first code is 'D9ZZ'
the next code should be 'E0AA'
sorry maybe my example is quite confusing.. here's another example.. thanks.
first code is 'D9AZ'
the next code should be 'D9BA'

string start = "A9ZZ";
int add = 1;
string next = String.Concat(start.Reverse().Select((x,i) =>
{
char first = i == 2 ? '0' : 'A';
char last = i == 2 ? '9' : 'Z';
if ((x += (char)add) > last)
{
return first;
}
else
{
add = 0;
return x;
}
})
.Reverse());

This should fix it.
private static IEnumerable<string> Increment(string value)
{
if (value.Length != 4)
throw new ArgumentException();
char[] next = value.ToCharArray();
while (new string(next) != "Z9ZZ")
{
next[3]++;
if (next[3] > 'Z')
{
next[3] = 'A';
next[2]++;
}
if (next[2] > 'Z')
{
next[2] = 'A';
next[1]++;
}
if (next[1] > '9')
{
next[1] = '0';
next[0]++;
}
yield return new string(next);
}
}
Example of calling this code:
IList<string> values = Increment("A0AA").Take(100).ToList();
foreach (var value in values)
{
Console.Write(value + " ");
}

Here's a pretty clean solution that checks every character starting at the end:
public SomeMethod()
{
var next = Increment("A2CZ"); // A2DZ
}
public string Increment(string code)
{
var arr = code.ToCharArray();
for (var i = arr.Length - 1; i >= 0; i--)
{
var c = arr[i];
if (c == 90 || c == 57)
continue;
arr[i]++;
return new string(arr);
}
return code;
}

c# finding characters between brackets

I can't get it to work,
I need to get a character ex : i [L]ove [B]asketball and [H]ockey
i would like to take the L, B and H out of this string and show them in a console writeline
without using regex
I though about finding the position of [ with an indexof and add + 1 to get the letter and then replace the [ with something else ex: [ into &
so i could do a foreach bracket in that string... but i don't think it'll work o.O
Console.WriteLine("Characters are : ");
foreach(Brackets in sentence)..

string str = " i [L]ove [B]asketball and [H]ockey";
string[] array = str.Split('[');
foreach (var item in array)
{
if(item.Contains(']'))
Console.WriteLine(item[0]);
}
and you will get:
L
B
H
This would work as long as you don't have unpaired square brackets and there is a character between those square brackets.

You can do this without the split:
string str = " i [L]ove [B]asketball and [H]ockey";
for (int i = 0; i < str.Length; i++)
{
if(str[i] == '[')
Console.WriteLine(str[1 + i++]);
}

Using LINQ:
string s = "i [L]ove [B]asketball and [H]ockey";
var chars = s.Where((c, i) => i > 0 && s[i - 1] == '[' &&
i < s.Length - 1 && s[i + 1] == ']');
Equivalently:
var chars = Enumerable.Range(1, s.Length - 2)
.Where(i => s[i - 1] == '[' && s[i + 1] == ']')
.Select(i => s[i]);

You can use this regex to get the values between the brakets:
string input = "I [L]ove [B]asketball and [H]ockey";
var regex = new Regex(#"\[.*?\]");
var matches = regex.Matches(input);
foreach (var match in matches)
{
var letter = Regex.Replace(match.ToString(), #"\[|\]", string.Empty);
Console.WriteLine(letter);
}

With regex:
string str = " i [L]ove [B]asketball and [H]ockey";
Match match = Regex.Match(str, #"\[(.*?)\]");
StringBuilder sb = new StringBuilder();
//iterate over all matches
do
{
sb.Append(match);
match = match.NextMatch();
}while(match.Success); //condition
//note: Dump() only works in linqpad. Use Console.WriteLine() instead
sb.Dump();
//without brackets:
sb.ToString().Split(new []{'[',']'}, StringSplitOptions.RemoveEmptyEntries).Dump();

I have come up with lengthy code but it works with all the cases
Try This:
static void Main()
{
string line = "i [L]ove [B]asketball and [H]ockey";
int count = 0;
char temp=' ';
string str="";
foreach (char ch in line)
{
if (ch == '[')
{
count++;
}
else if (count ==1)
{
count++;
temp=ch;
}
else if(count==2 && ch==']')
{
str+=temp;
count=0;
}
else
{
count = 0;
}
}
Console.WriteLine(str);
}

C# Regular Expression to insert "_" after third, then seventh character with a new line after the eighth character

I was wondering if someone could help. I am trying to change a string in the below format:
goeirjew98rut34ktljre9t30t4j3der
to be outputted as below:
geo_irje_w
98r_ut34_k
tlj_re9t_3
0t4_j3de_r
So insert an underscore after the third and seventh characters and insert a new line after the eighth.
After doing some reading I thought the best way to do this might be via a regular expression such as the example at the below link:
http://msdn.microsoft.com/en-us/library/xwewhkd1(v=vs.110).aspx
However I am not sure how to modify this for my needs. Any help what so ever would be greatly appreciated.
Thanks

It can be easily solved by a regular expression and a Replace, like this:
var s = "goeirjew98rut34ktljre9t30t4j3der";
Regex.Replace(s, #"(\w{3})(\w{4})(\w{1})", "$1_$2_$3\n").Dump();

This is definitely something that is best solved with a quick loop:
string s = "goeirjew98rut34ktljre9t30t4j3der";
var outputs = new List<string>();
for (var i = 0; i < s.Length; i += 8)
{
string sub = s.Substring(i, Math.Min(8, s.Length - i));
if(sub.Length > 3)
sub = sub.Insert(3, "_");
if (sub.Length > 8)
sub = sub.Insert(8, "_");
outputs.Add(sub);
}

I think you can not insert char in string by this rule, but I hope this code be useful for you.
public string Decode(string str)
{
var state = 0;
var c = 0;
var newStr = string.Empty;
foreach (var ch in str)
{
c++;
newStr += ch;
if (state == 0 && c == 3)
{
newStr += "_";
state = 1;
c = 0;
}
if (state == 1 && c == 4)
{
newStr += "_";
state = 2;
c = 0;
}
if (state == 2 && c == 1)
{
newStr += "\r\n";
state = 0;
c = 0;
}
}
return newStr;
}

I would make it so u can change everything on the fly and use stringextentions
class Program
{
static void Main(string[] args)
{
string str = "goeirjew98rut34ktljre9t30t4j3der";
var parts = str.SplitInParts(8); //Split in different parts
foreach (var part in parts)
{
string formattedString = part.MultiInsert("_", 2, 6); //Insert your char on all position u want
Console.WriteLine(formattedString);
}
Console.ReadKey();
}
}
static class StringExtensions
{
public static IEnumerable<String> SplitInParts(this String s, Int32 partLength)
{
if (s == null)
throw new ArgumentNullException("s");
if (partLength <= 0)
throw new ArgumentException("Part length has to be positive.", "partLength");
for (var i = 0; i < s.Length; i += partLength)
yield return s.Substring(i, Math.Min(partLength, s.Length - i));
}
public static string MultiInsert(this string str, string insertChar, params int[] positions)
{
StringBuilder sb = new StringBuilder(str.Length + (positions.Length * insertChar.Length));
var posLookup = new HashSet<int>(positions);
for (int i = 0; i < str.Length; i++)
{
sb.Append(str[i]);
if (posLookup.Contains(i))
sb.Append(insertChar);
}
return sb.ToString();
}
}