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remove string between "|" and "," in stringbuilder in C#

I use VS2019 in Windows7.
I want to remove string between "|" and "," in a StringBuilder.
That is , I want to convert StringBuilder from
"578.552|0,37.986|317,38.451|356,23"
to
"578.552,37.986,38.451,23"
I have tried Substring but failed, what other method I could use to achieve this?

If you have a huge StringBuilder and that's why converting it into String and applying regular expression is not the option,
you can try implementing Finite State Machine (FSM):
StringBuilder source = new StringBuilder("578.552|0,37.986|317,38.451|356,23");
int state = 0; // 0 - keep character, 1 - discard character
int index = 0;
for (int i = 0; i < source.Length; ++i) {
char c = source[i];
if (state == 0)
if (c == '|')
state = 1;
else
source[index++] = c;
else if (c == ',') {
state = 0;
source[index++] = c;
}
}
source.Length = index;

StringBuilder isn't really setup for much by way of inspection and mutation in the middle. It would be pretty easy to do once you have a string (probably via a Regex), but StringBuilder? not so much. In reality, StringBuilder is mostly intended for forwards-only append, so the answer would be:
if you didn't want those characters, why did you add them?
Maybe just use the string version here; then:
var s = "578.552|0,37.986|317,38.451|356,23";
var t = Regex.Replace(s, #"\|.*?(?=,)", ""); // 578.552,37.986,38.451,23
The regex translation here is "pipe (\|), non-greedy anything (.*?), followed by a comma where the following comma isn't part of the match ((?=,)).

If you don't know very much of Regex patterns, you can write your own custom method to filter out data; its always instructive and a good practicing exercise:
public static String RemoveDelimitedSubstrings(
this StringBuilder s,
char startDelimitter,
char endDelimitter,
char newDelimitter)
{
var buffer = new StringBuilder(s.Length);
var ignore = false;
for (var i = 0; i < s.Length; i++)
{
var currentChar = s[i];
if (currentChar == startDelimitter && !ignore)
{
ignore = true;
}
else if (currentChar == endDelimitter && ignore)
{
ignore = false;
buffer.Append(newDelimitter);
}
else if (!ignore)
buffer.Append(currentChar);
}
return buffer.ToString();
}
And youd obvisouly use it like:
var buffer= new StringBuilder("578.552|0,37.986|317,38.451|356,23");
var filteredBuffer = b.RemoveDelimitedSubstrings('|', ',', ','));

C# Concatenate strings or array of chars

I'm facing a problem while developing an application.
Basically,
I have a fixed string, let's say "IHaveADream"
I now want to user to insert another string, for my purpose of a fixed length, and then concatenate every character of the fixed string with every character of the string inserted by the user.
e.g.
The user inserts "ByeBye"
then the output would be:
"IBHyaevBeyAeDream".
How to accomplish this?
I have tried with String.Concat and String.Join, inside a for statement, with no luck.

One memory-efficient option is to use a string builder, since both the original string and the user input could potentially be rather large. As mentioned by Kris, you can initialize your StringBuilder capacity to the combined length of both strings.
void Main()
{
var start = "IHaveADream";
var input = "ByeBye";
var sb = new StringBuilder(start.Length + input.Length);
for (int i = 0; i < start.Length; i++)
{
sb.Append(start[i]);
if (input.Length >= i + 1)
sb.Append(input[i]);
}
sb.ToString().Dump();
}
This only safely accounts for the input string being shorter or equal in length to the starting string. If you had a longer input string, you'd want to take the longer length as the end point for your for loop iteration and check that each array index is not out of bounds.
void Main()
{
var start = "IHaveADream";
var input = "ByeByeByeByeBye";
var sb = new StringBuilder(start.Length + input.Length);
var length = start.Length >= input.Length ? start.Length : input.Length;
for (int i = 0; i < length; i++)
{
if (start.Length >= i + 1)
sb.Append(start[i]);
if (input.Length >= i + 1)
sb.Append(input[i]);
}
sb.ToString().Dump();
}

You can create an array of characters and then re-combine them in the order you want.
char[] chars1 = "IHaveADream".ToCharArray();
char[] chars2 = "ByeBye".ToCharArray();
// you can create a custom algorithm to handle
// different size strings.
char[] c = new char[17];
c[0] = chars1[0];
c[1] = chars2[0];
...
c[13] = chars1[10];
string s = new string(c);

var firstString = "Ihaveadream";
var secondString = "ByeBye";
var stringBuilder = new StringBuilder();
for (int i = 0; i< firstString.Length; i++) {
stringBuilder .Append(str[i]);
if (i < secondString.Length) {
stringBuilder .Append(secondStr[i]);
}
}
var result = stringBuilder.ToString();

If you don't care much about memory usage or perfomance you can just use:
public static string concatStrings(string value, string value2)
{
string result = "";
int i = 0;
for (i = 0; i < Math.Max(value.Length, value2.Length) ; i++)
{
if (i < value.Length) result += value[i].ToString();
if (i < value2.Length) result += value2[i].ToString();
}
return result;
}
Usage:
string conststr = "IHaveADream";
string input = "ByeBye";
var result = ConcatStrings(conststr, input);
Console.WriteLine(result);
Output: IBHyaevBeyAeDream
P.S.
Just checked perfomance of both methods (with strBuilder and simple cancatenation) and it appears to be that both of this methods take same time to execute (if you have just one operation). The main reason for it is that string builder take considerable time to initialize while with use of concatenation we don't need that.
But in case if you have to process something like 1500 strings then it's different story and string builder is more of an option.
For 100 000 method executions it showed 85 (str buld) vs 22 (concat) ms respectively.
My Code

How to add symbols automatically in c#?

I'm beginning programming with C# and have a question:
I have a string of character like abcdef123456789. But the string is too long, therefore I want to add : automatically, after the second, fourth, six .... symbol.
How can I do that?

There is no built in method that does something like that. You just have to put the separators in there by looping through the string.
You can loop though the characters and put them in a StringBuilder, adding a colon at every other character:
string input = "abcdef123456789";
StringBuilder builder = new StringBuilder();
int cnt = 0;
foreach (char c in input) {
if (cnt == 2) {
builder.Append(':');
cnt = 0;
}
builder.Append(c);
cnt++;
}
string output = builder.ToString();

You could try this approach. I've attempted to make it as readable as possible, so hopefully it makes sense to you.
var s = "abcdef123456789";
var charsChanged = new List<char>();
for (var i = 0; i < s.Length; i++)
{
charsChanged.Add(s[i]);
var evenCharacter = i % 2 != 0;
var atEndOfString = i == s.Length - 1;
if (evenCharacter && !atEndOfString)
{
charsChanged.Add(':');
}
}
var updatedString = string.Concat(charsChanged));
updatedString will equal ab:cd:ef:12:34:56:78:9.
This approach makes use of the modulus operator (%) to determine if we're at an even or odd character. For more examples, check this out.

You can use a StringBuilder and do something like this:
string sourceStr = "123456789";
StringBuilder s = new StringBuilder();
foreach(char c in sourceStr){
s.append(c);
s.append(":");
}

Better way for the special concatenation of two strings

I want to concatenate two strings in such a way, that after the first character of the first string, the first character of second string comes, and then the second character of first string comes and then the second character of the second string comes and so on. Best explained by some example cases:
s1="Mark";
s2="Zukerberg"; //Output=> MZaurkkerberg
if:
s1="Zukerberg";
s2="Mark" //Output=> ZMuakrekrberg
if:
s1="Zukerberg";
s2="Zukerberg"; //Output=> ZZuukkeerrbbeerrgg
I've written the following code which gives the expected output but its seems to be a lot of code. Is there any more efficient way for doing this?
public void SpecialConcat(string s1, string s2)
{
string[] concatArray = new string[s1.Length + s2.Length];
int k = 0;
string final = string.Empty;
string superFinal = string.Empty;
for (int i = 0; i < s1.Length; i++)
{
for (int j = 0; j < s2.Length; j++)
{
if (i == j)
{
concatArray[k] = s1[i].ToString() + s2[j].ToString();
final = string.Join("", concatArray);
}
}
k++;
}
if (s1.Length > s2.Length)
{
string subOne = s1.Remove(0, s2.Length);
superFinal = final + subOne;
}
else if (s2.Length > s1.Length)
{
string subTwo = s2.Remove(0, s1.Length);
superFinal = final + subTwo;
}
else
{
superFinal = final;
}
Response.Write(superFinal);
}
}
I have written the same logic in Javascript also, which works fine but again a lot of code.

var s1 = "Mark";
var s2 = "Zukerberg";
var common = string.Concat(s1.Zip(s2, (a, b) => new[]{a, b}).SelectMany(c => c));
var shortestLength = Math.Min(s1.Length, s2.Length);
var result =
common + s1.Substring(shortestLength) + s2.Substring(shortestLength);

var stringBuilder = new StringBuilder();
for (int i = 0; i < Math.Max(s1.Length, s2.Length); i++)
{
if (i < s1.Length)
stringBuilder.Append(s1[i]);
if (i < s2.Length)
stringBuilder.Append(s2[i]);
}
string result = stringBuilder.ToString();

In JavaScript, when working with strings, you are also working with arrays, so it will be easier. Also + will concatenate for you. Replace string indexing with charAt if you want IE7- support.
Here is the fiddle:
http://jsfiddle.net/z6XLh/1
var s1 = "Mark";
var s2 = "ZuckerFace";
var out ='';
var l = s1.length > s2.length ? s1.length : s2.length
for(var i = 0; i < l; i++) {
if(s1[i]) {
out += s1[i];
}
if(s2[i]){
out += s2[i];
}
}
console.log(out);

static string Join(string a, string b)
{
string returnVal = "";
int length = Math.Min(a.Length, b.Length);
for (int i = 0; i < length; i++)
returnVal += "" + a[i] + b[i];
if (a.Length > length)
returnVal += a.Substring(length);
else if(b.Length > length)
returnVal += b.Substring(length);
return returnVal;
}
Could possibly be improved through stringbuilder

Just for the sake of curiosity, here's an unreadable one-liner (which I have nevertheless split over multiple lines ;))
This uses the fact that padding a string to a certain length does nothing if the string is already at least that length. That means padding each string to the length of the other string will have the result of padding out with spaces the shorter one to the length of the longer one.
Then we use .Zip() to concatenate each of the pairs of characters into a string.
Then we call string.Concat(IEnumerable<string>) to concatenate the zipped strings into a single string.
Finally, we remove the extra padding spaces we introduced earlier by using string.Replace().
var result = string.Concat
(
s1.PadRight(s2.Length)
.Zip
(
s2.PadRight(s1.Length),
(a,b)=>string.Concat(a,b)
)
).Replace(" ", null);
On one line [insert Coding Horror icon here]:
var result = string.Concat(s1.PadRight(s2.Length).Zip(s2.PadRight(s1.Length), (a,b)=>string.Concat(a,b))).Replace(" ", null);

Just off the top of my head, this is how I might do it.
var s1Length = s1.Length;
var s2Length = s2.Length;
var count = 0;
var o = "";
while (s1Length + s2Length > 0) {
if (s1Length > 0) {
s1Length--;
o += s1[count];
}
if (s2Length > 0) {
s2Length--;
o += s2[count];
}
count++;
}

Here's another one-liner:
var s1 = "Mark";
var s2 = "Zukerberg";
var result = string.Join("",
Enumerable.Range(0, s1.Length).ToDictionary(x => x * 2, x => s1[x])
.Concat(Enumerable.Range(0, s2.Length).ToDictionary(x => x * 2+1, x => s2[x]))
.OrderBy(d => d.Key).Select(d => d.Value));
Basically, this converts both strings into dictionaries with keys that will get the resulting string to order itself correctly. The Enumerable range is used to associate an index with each letter in the string. When we store the dictionaries, it multiplies the index on s1 by 2, resulting in <0,M>,<2,a>,<4,r>,<6,k>, and multiplies s2 by 2 then adds 1, resulting in <1,Z>,<3,u>,<5,k>, etc.
Once we have these dictionaries, we combine them with the .Concat and sort them with the .OrderBy,which gives us <0,M>,<1,Z>,<2,a>,<3,u>,... Then we just dump them into the final string with the string.join at the beginning.

Ok, this is the *second shortest solution I could come up with:
public string zip(string s1, string s2)
{
return (string.IsNullOrWhiteSpace(s1+s2))
? (s1[0] + "" + s2[0] + zip(s1.Substring(1) + " ", s2.Substring(1) + " ")).Replace(" ", null)
: "";
}
var result = zip("mark","zukerberg");
Whoops! My original shortest was the same as mark's above...so, second shortest i could come up with! I had hoped I could really trim it down with the recursion, but not so much.

var sWordOne = "mark";// ABCDEF
var sWordTwo = "zukerberg";// 123
var result = (sWordOne.Length > sWordTwo.Length) ? zip(sWordOne, sWordTwo) : zip(sWordTwo, sWordOne);
//result = "zmuakrekrberg"
static string zip(string sBiggerWord, string sSmallerWord)
{
if (sBiggerWord.Length < sSmallerWord.Length) return string.Empty;// Invalid
if (sSmallerWord.Length == 0) sSmallerWord = " ";
return string.IsNullOrEmpty(sBiggerWord) ? string.Empty : (sBiggerWord[0] + "" + sSmallerWord[0] + zip(sBiggerWord.Substring(1),sSmallerWord.Substring(1))).Replace(" ","");
}

A simple alternative without Linq witchcraft:
string Merge(string one, string two)
{
var buffer = new char[one.Length + two.Length];
var length = Math.Max(one.Length, two.Length);
var index = 0;
for (var i = 0; i < length; i ++)
{
if (i < one.Length) buffer[index++] = one[i];
if (i < two.Length) buffer[index++] = two[i];
}
return new string(buffer);
}

Split a string without separator

I have a string variable with value
"abcdefghijklmnop".
Now I want to split the string into string array with, say, three characters (the last array element may contain fewer) in each array element from the right end.
I.e.,
"a"
"bcd"
"efg"
"hij"
"klm"
"nop"
What is the easiest and simplest way to do this?? (Both Visual Basic and C# code is welcome)?

Here's a solution:
var input = "abcdefghijklmnop";
var result = new List<string>();
int incompleteGroupLength = input.Length % 3;
if (incompleteGroupLength > 0)
result.Add(input.Substring(0, incompleteGroupLength));
for (int i = incompleteGroupLength; i < input.Length; i+=3)
{
result.Add(input.Substring(i, 3));
}
It gives the expected output of:
"a"
"bcd"
"efg"
"hij"
"klm"
"nop"

Here's something that works - wrapped up into a string extension function.
namespace System
{
public static class StringExts
{
public static IEnumerable<string> ReverseCut(this string txt, int cutSize)
{
int first = txt.Length % cutSize;
int taken = 0;
string nextResult = new String(txt.Take(first).ToArray());
taken += first;
do
{
if (nextResult.Length > 0)
yield return nextResult;
nextResult = new String(txt.Skip(taken).Take(cutSize).ToArray());
taken += cutSize;
} while (nextResult.Length == cutSize);
}
}
}
Usage:
textBox2.Text = "";
var txt = textBox1.Text;
foreach (string s in txt.ReverseCut(3))
textBox2.Text += s + "\r\n";

Regex time!!
Regex rx = new Regex("^(.{1,2})??(.{3})*$");
var matches = rx.Matches("abcdefgh");
var pieces = matches[0].Groups[1].Captures.OfType<Capture>().Select(p => p.Value).Concat(matches[0].Groups[2].Captures.OfType<Capture>().Select(p => p.Value)).ToArray();
pieces will contain:
"ab"
"cde"
"fgh"
(Please, don't use this code! It is only an example of what can happen when you use a regular expression + LINQ.)

Well... here is yet another way I arrived at:
private string[] splitIntoAry(string str)
{
string[] temp = new string[(int)Math.Ceiling((double)str.Length / 3)];
while (str != string.Empty)
{
temp[(int)Math.Ceiling((double)str.Length / 3) - 1] = str.Substring(str.Length - Math.Min(str.Length, 3));
str = str.Substring(0, str.Length - Math.Min(str.Length, 3));
}
return temp;
}