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C#: Need to split a string into a string[] and keeping the delimiter (also a string) at the beginning of the string

I think I am too dumb to solve this problem...
I have some formulas which need to be "translated" from one syntax to another.
Let's say I have a formula that goes like that (it's a simple one, others have many "Ceilings" in it):
string formulaString = "If([Param1] = 0, 1, Ceiling([Param2] / 0.55) * [Param3])";
I need to replace "Ceiling()" with "Ceiling(; 1)" (basically, insert "; 1" before the ")").
My attempt is to split the fomulaString at "Ceiling(" so I am able to iterate through the string array and insert my string at the correct index (counting every "(" and ")" to get the right index)
What I have so far:
//splits correct, but loses "CEILING("
string[] parts = formulaString.Split(new[] { "CEILING(" }, StringSplitOptions.None);
//splits almost correct, "CEILING(" is in another group
string[] parts = Regex.Split(formulaString, #"(CEILING\()");
//splits almost every letter
string[] parts = Regex.Split(formulaString, #"(?=[(CEILING\()])");
When everything is done, I concat the string so I have my complete formula again.
What do I have to set as Regex pattern to achieve this sample? (Or any other method that will help me)
part1 = "If([Param1] = 0, 1, ";
part2 = "Ceiling([Param2] / 0.55) * [Param3])";
//part3 = next "CEILING(" in a longer formula and so on...

As I mention in a comment, you almost got it: (?=Ceiling). This is incomplete for your use case unfortunately.
I need to replace "Ceiling()" with "Ceiling(; 1)" (basically, insert "; 1" before the ")").
Depending on your regex engine (for example JS) this works:
string[] parts = Regex.Split(formulaString, #"(?<=Ceiling\([^)]*(?=\)))");
string modifiedFormula = String.join("; 1", parts);
The regex
(?<=Ceiling\([^)]*(?=\)))
(?<= ) Positive lookbehind
Ceiling\( Search for literal "Ceiling("
[^)] Match any char which is not ")" ..
* .. 0 or more times
(?=\)) Positive lookahead for ")", effectively making us stop before the ")"
This regex is a zero-assertion, therefore nothing is lost and it will cut your strings before the last ")" in every "Ceiling()".
This solution would break whenever you have nested "Ceiling()". Then your only solution would be writing your own parser for the same reasons why you can't parse markup with regex.

Regex.Replace(formulaString, #"(?<=Ceiling\()(.*?)(?=\))","$1; 1");
Note: This will not work for nested "Ceilings", but it does for Ceiling(), It will also not work fir Ceiling(AnotherFunc(x)). For that you need something like:
Regex.Replace(formulaString, #"(?<=Ceiling\()((.*\((?>[^()]+|(?1))*\))*|[^\)]*)(\))","$1; 1$3");
but I could not get that to work with .NET, only in JavaScript.

This is my solution:
private string ConvertCeiling(string formula)
{
int ceilingsCount = formula.CountOccurences("Ceiling(");
int startIndex = 0;
int bracketCounter;
for (int i = 0; i < ceilingsCount; i++)
{
startIndex = formula.IndexOf("Ceiling(", startIndex);
bracketCounter = 0;
for (int j = 0; j < formula.Length; j++)
{
if (j < startIndex) continue;
var c = formula[j];
if (c == '(')
{
bracketCounter++;
}
if (c == ')')
{
bracketCounter--;
if (bracketCounter == 0)
{
// found end
formula = formula.Insert(j, "; 1");
startIndex++;
break;
}
}
}
}
return formula;
}
And CountOccurence:
public static int CountOccurences(this string value, string parameter)
{
int counter = 0;
int startIndex = 0;
int indexOfCeiling;
do
{
indexOfCeiling = value.IndexOf(parameter, startIndex);
if (indexOfCeiling < 0)
{
break;
}
else
{
startIndex = indexOfCeiling + 1;
counter++;
}
} while (true);
return counter;
}

C# read string from back to end

I have a string. For example :
string a = "abcdef098403248";
My goal is, knowing that the string ends with a number (else something like this will happen : MessageBox.Show("String doesnt end in a number"); ), i want to read the string, starting from the end to the begining, and store the values in another string.
Now the only problem is, i can only store in that new string numbers, and when i read the string a , while i count from the back to end if i find a character that isnt a number, i stop reading and store the previous numbers found in the new string. The code output should look somthing like this:
string a = "aBcdef3213BBBBB0913456";
//part were i read the string from back to end
string finalString = "0913456";
As you see there, i store the numbers from left to right, but i want to read them from right to left.
Another example of what i want:
string a = "aaaaa3a224444";
// part were i read the string from back to end
string finalString = "224444";
Or:
string a = "3333333a224444";
// part were i read the string from back to end
string finalString = "224444";
Regardless, thanks.

Stack<char> is your friend:
var stack = new Stack<char>();
foreach (var c in a.Reverse())
{
if (!char.IsDigit(c))
break;
stack.Push(c);
}
return new string(stack.ToArray());

Reverse the string using the function below.
Grab the number the wrong way around - spin it back.
public static string Reverse( string s )
{
char[] charArray = s.ToCharArray();
Array.Reverse( charArray );
return new string( charArray );
}
Taken from : Best way to reverse a string

string str = "3333333a224444";
var reversedStr = str.Reverse();
string result= new String(reversedStr.TakeWhile(Char.IsDigit).ToArray());

I came up with this. Not as elegant as others. It adds the numbers to the string until it encounters a letter again then stops.
string a = "aBcdef3213BBBBB0913456";
var charList = a.ToCharArray();
string newString = string.Empty;
foreach (var letter in charList.Reverse())
{
var number = 0;
if (Int32.TryParse(letter.ToString(), out number))
{
newString = string.Format("{0}{1}", letter, newString);
}
else
{
break;
}
}

string a = "saffsa1ad12314";
string finalString = string.Empty;
char[] chars = a.ToCharArray();
for (int i = chars.Length -1; i >= 0; i--)
{
if (char.IsDigit(chars[i]))
{
finalString += chars[i];
}
else
{
break; //so you dont get a number after a letter
//could put your mbox here
}
}
//Now you just have to reverse the string
char[] revMe = finalString.ToCharArray();
Array.Reverse(revMe);
finalString = string.Empty;
foreach (char x in revMe)
{
finalString += x;
}
Console.WriteLine(finalString);
//outputs: 12314
This question feels awfully homeworky - but here is a very verbose way
of solving your problem. Alternatively you can read up on regex in c#.

C# How to generate a new string based on multiple ranged index

Let's say I have a string like this one, left part is a word, right part is a collection of indices (single or range) used to reference furigana (phonetics) for kanjis in my word:
string myString = "子で子にならぬ時鳥,0:こ;2:こ;7-8:ほととぎす"
The pattern in detail:
word,<startIndex>(-<endIndex>):<furigana>
What would be the best way to achieve something like this (with a space in front of the kanji to mark which part is linked to the [furigana]):
子[こ]で 子[こ]にならぬ 時鳥[ほととぎす]
Edit: (thanks for your comments guys)
Here is what I wrote so far:
static void Main(string[] args)
{
string myString = "ABCDEF,1:test;3:test2";
//Split Kanjis / Indices
string[] tokens = myString.Split(',');
//Extract furigana indices
string[] indices = tokens[1].Split(';');
//Dictionnary to store furigana indices
Dictionary<string, string> furiganaIndices = new Dictionary<string, string>();
//Collect
foreach (string index in indices)
{
string[] splitIndex = index.Split(':');
furiganaIndices.Add(splitIndex[0], splitIndex[1]);
}
//Processing
string result = tokens[0] + ",";
for (int i = 0; i < tokens[0].Length; i++)
{
string currentIndex = i.ToString();
if (furiganaIndices.ContainsKey(currentIndex)) //add [furigana]
{
string currentFurigana = furiganaIndices[currentIndex].ToString();
result = result + " " + tokens[0].ElementAt(i) + string.Format("[{0}]", currentFurigana);
}
else //nothing to add
{
result = result + tokens[0].ElementAt(i);
}
}
File.AppendAllText(#"D:\test.txt", result + Environment.NewLine);
}
Result:
ABCDEF,A B[test]C D[test2]EF
I struggle to find a way to process ranged indices:
string myString = "ABCDEF,1:test;2-3:test2";
Result : ABCDEF,A B[test] CD[test2]EF

I don't have anything against manually manipulating strings per se. But given that you seem to have a regular pattern describing the inputs, it seems to me that a solution that uses regex would be more maintainable and readable. So with that in mind, here's an example program that takes that approach:
class Program
{
private const string _kinvalidFormatException = "Invalid format for edit specification";
private static readonly Regex
regex1 = new Regex(#"(?<word>[^,]+),(?<edit>(?:\d+)(?:-(?:\d+))?:(?:[^;]+);?)+", RegexOptions.Compiled),
regex2 = new Regex(#"(?<start>\d+)(?:-(?<end>\d+))?:(?<furigana>[^;]+);?", RegexOptions.Compiled);
static void Main(string[] args)
{
string myString = "子で子にならぬ時鳥,0:こ;2:こ;7-8:ほととぎす";
string result = EditString(myString);
}
private static string EditString(string myString)
{
Match editsMatch = regex1.Match(myString);
if (!editsMatch.Success)
{
throw new ArgumentException(_kinvalidFormatException);
}
int ichCur = 0;
string input = editsMatch.Groups["word"].Value;
StringBuilder text = new StringBuilder();
foreach (Capture capture in editsMatch.Groups["edit"].Captures)
{
Match oneEditMatch = regex2.Match(capture.Value);
if (!oneEditMatch.Success)
{
throw new ArgumentException(_kinvalidFormatException);
}
int start, end;
if (!int.TryParse(oneEditMatch.Groups["start"].Value, out start))
{
throw new ArgumentException(_kinvalidFormatException);
}
Group endGroup = oneEditMatch.Groups["end"];
if (endGroup.Success)
{
if (!int.TryParse(endGroup.Value, out end))
{
throw new ArgumentException(_kinvalidFormatException);
}
}
else
{
end = start;
}
text.Append(input.Substring(ichCur, start - ichCur));
if (text.Length > 0)
{
text.Append(' ');
}
ichCur = end + 1;
text.Append(input.Substring(start, ichCur - start));
text.Append(string.Format("[{0}]", oneEditMatch.Groups["furigana"]));
}
if (ichCur < input.Length)
{
text.Append(input.Substring(ichCur));
}
return text.ToString();
}
}
Notes:
This implementation assumes that the edit specifications will be listed in order and won't overlap. It makes no attempt to validate that part of the input; depending on where you are getting your input from you may want to add that. If it's valid for the specifications to be listed out of order, you can also extend the above to first store the edits in a list and sort the list by the start index before actually editing the string. (In similar fashion to the way the other proposed answer works; though, why they are using a dictionary instead of a simple list to store the individual edits, I have no idea…that seems arbitrarily complicated to me.)
I included basic input validation, throwing exceptions where failures occur in the pattern matching. A more user-friendly implementation would add more specific information to each exception, describing what part of the input actually was invalid.
The Regex class actually has a Replace() method, which allows for complete customization. The above could have been implemented that way, using Replace() and a MatchEvaluator to provide the replacement text, instead of just appending text to a StringBuilder. Which way to do it is mostly a matter of preference, though the MatchEvaluator might be preferred if you have a need for more flexible implementation options (i.e. if the exact format of the result can vary).
If you do choose to use the other proposed answer, I strongly recommend you use StringBuilder instead of simply concatenating onto the results variable. For short strings it won't matter much, but you should get into the habit of always using StringBuilder when you have a loop that is incrementally adding onto a string value, because for long string the performance implications of using concatenation can be very negative.

This should do it (and even handle ranged indices), based on the formatting of the input string you have-
using System;
using System.Collections.Generic;
public class stringParser
{
private struct IndexElements
{
public int start;
public int end;
public string value;
}
public static void Main()
{
//input string
string myString = "子で子にならぬ時鳥,0:こ;2:こ;7-8:ほととぎす";
int wordIndexSplit = myString.IndexOf(',');
string word = myString.Substring(0,wordIndexSplit);
string indices = myString.Substring(wordIndexSplit + 1);
string[] eachIndex = indices.Split(';');
Dictionary<int,IndexElements> index = new Dictionary<int,IndexElements>();
string[] elements;
IndexElements e;
int dash;
int n = 0;
int last = -1;
string results = "";
foreach (string s in eachIndex)
{
e = new IndexElements();
elements = s.Split(':');
if (elements[0].Contains("-"))
{
dash = elements[0].IndexOf('-');
e.start = int.Parse(elements[0].Substring(0,dash));
e.end = int.Parse(elements[0].Substring(dash + 1));
}
else
{
e.start = int.Parse(elements[0]);
e.end = e.start;
}
e.value = elements[1];
index.Add(n,e);
n++;
}
//this is the part that takes the "setup" from the parts above and forms the result string
//loop through each of the "indices" parsed above
for (int i = 0; i < index.Count; i++)
{
//if this is the first iteration through the loop, and the first "index" does not start
//at position 0, add the beginning characters before its start
if (last == -1 && index[i].start > 0)
{
results += word.Substring(0,index[i].start);
}
//if this is not the first iteration through the loop, and the previous iteration did
//not stop at the position directly before the start of the current iteration, add
//the intermediary chracters
else if (last != -1 && last + 1 != index[i].start)
{
results += word.Substring(last + 1,index[i].start - (last + 1));
}
//add the space before the "index" match, the actual match, and then the formatted "index"
results += " " + word.Substring(index[i].start,(index[i].end - index[i].start) + 1)
+ "[" + index[i].value + "]";
//remember the position of the ending for the next iteration
last = index[i].end;
}
//if the last "index" did not stop at the end of the input string, add the remaining characters
if (index[index.Keys.Count - 1].end + 1 < word.Length)
{
results += word.Substring(index[index.Keys.Count-1].end + 1);
}
//trimming spaces that may be left behind
results = results.Trim();
Console.WriteLine("INPUT - " + myString);
Console.WriteLine("OUTPUT - " + results);
Console.Read();
}
}
input - 子で子にならぬ時鳥,0:こ;2:こ;7-8:ほととぎす
output - 子[こ]で 子[こ]にならぬ 時鳥[ほととぎす]
Note that this should also work with characters the English alphabet if you wanted to use English instead-
input - iliketocodeverymuch,2:A;4-6:B;9-12:CDEFG
output - il i[A]k eto[B]co deve[CDEFG]rymuch

C# - split a RichTextBox line in two based on the caret position

I've got a RichTextBox, here referred to as box.
string currentline = box.Lines[box.GetLineFromCharIndex(box.SelectionStart)];
That line there fetches the line the caret is in. It works excellently.
However, I have a need to get two strings from this. The first is everything on that line UP to the caret, and the second is everything on that line AFTER it.
For instance, if the line is How is you|r day going?, with | representing the caret, I would get How is you and r day going?, separately.
I wrote this monstrosity, which works:
string allbefore = box.Text.Substring(0, box.SelectionStart);
string allafter = box.Text.Substring(box.SelectionStart, box.Text.Length - box.SelectionStart);
string linebefore = "";
for (int i = 0; i < allbefore.Length; i++)
{
linebefore += allbefore[i];
if (allbefore[i] == '\n')
linebefore = "";
}
string lineafter = "";
for (int i = 0; i < allafter.Length; i++)
{
if (allafter[i] == '\n')
break;
else
lineafter += allafter[i];
}
It gives me the result I want, but involves looping through EVERY character in the entire box, which just hurts. Is there an easy way to do this I'm just missing? Thanks.

This might do the trick for you
string currentline = box.Lines[box.GetLineFromCharIndex(box.SelectionStart)];
var listOfStrings = new List<string>();
string[] splitedBox = currentline.Split('|');
foreach(string sp in splitedBox)
{
string[] lineleft = sp.Split('\n');
listOfStrings.Add(lineleft[lineleft.Count() - 1]);
}
In the first approach we are splitting the line by char | than finding if we have any \n if it exsist we are taking the values accordingly
Another approach could be
string box = "How is \n you|r day \n going?";
bool alllinesremoved = true;
while(alllinesremoved)
{
if(box.Contains('\n'))
{
if(box.IndexOf('\n') > box.IndexOf('|'))
{
box = box.Remove(box.IndexOf('\n'), (box.Length - box.IndexOf('\n')));
}
else
{
box = box.Remove(0, box.IndexOf('\n') + 1);
}
}
else
{
alllinesremoved = false;
}
}
string[] splitedBox = box.Split('|');
in the second approach we are removing the characters before and after the \n and then splitting the string. I think the second one seems more good to me.

Have you tried using line.split? Not sure if this is what you want.

Store the position of \n using indexOf and, if >= 0, that is, the string contains it, use substring and assign the value otherwise.
string allbefore = box.Text.Substring(0, box.SelectionStart);
string allafter = box.Text.Substring(box.SelectionStart, box.Text.Length - box.SelectionStart);
int newLinePos = allBefore.lastIndexOf("\n");
string lineBefore = ((newLinePos >= 0) ? (allBefore.substring(newLinePos + 1)) : (allBefore));
newLinePos = allafter.indexOf("\n");
string lineAfter = ((newLinePost >= 0) ? (allAfter.substring(0, newLinePos)) : (allAfter));

Getting number from a string in C#

I am scraping some website content which is like this - "Company Stock Rs. 7100".
Now, what i want is to extract the numeric value from this string. I tried split but something or the other goes wrong with my regular expression.
Please let me know how to get this value.

Use:
var result = Regex.Match(input, #"\d+").Value;
If you want to find only number which is last "entity" in the string you should use this regex:
\d+$
If you want to match last number in the string, you can use:
\d+(?!\D*\d)

int val = int.Parse(Regex.Match(input, #"\d+", RegexOptions.RightToLeft).Value);

I always liked LINQ:
var theNumber = theString.Where(x => char.IsNumber(x));
Though Regex sounds like the native choice...

This code will return the integer at the end of the string. This will work better than the regular expressions in the case that there is a number somewhere else in the string.
public int getLastInt(string line)
{
int offset = line.Length;
for (int i = line.Length - 1; i >= 0; i--)
{
char c = line[i];
if (char.IsDigit(c))
{
offset--;
}
else
{
if (offset == line.Length)
{
// No int at the end
return -1;
}
return int.Parse(line.Substring(offset));
}
}
return int.Parse(line.Substring(offset));
}

If your number is always after the last space and your string always ends with this number, you can get it this way:
str.Substring(str.LastIndexOf(" ") + 1)

Here is my answer ....it is separating numeric from string using C#....
static void Main(string[] args)
{
String details = "XSD34AB67";
string numeric = "";
string nonnumeric = "";
char[] mychar = details.ToCharArray();
foreach (char ch in mychar)
{
if (char.IsDigit(ch))
{
numeric = numeric + ch.ToString();
}
else
{
nonnumeric = nonnumeric + ch.ToString();
}
}
int i = Convert.ToInt32(numeric);
Console.WriteLine(numeric);
Console.WriteLine(nonnumeric);
Console.ReadLine();
}
}
}

You can use \d+ to match the first occurrence of a number:
string num = Regex.Match(input, #"\d+").Value;