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How to bring back removed spaces

I have a string which has multiple spaces between the words and I want to remove these spaces and then bring them back .. The problem was in bringing the spaces back after deleting them I tried to code my idea but it runs without any output and some times it gives me an exception of "Index was outside of array bounds" .. any help
string pt = "My name is Code"
int ptLenght = pt.Length;
char[] buffer1 = pt.ToCharArray();
spaceHolder = new int[pt.Length];
for (int m = 0; m < pt.Length; m++)
{
if (buffer1[m] == ' ')
{
hold = m;
spaceHolder[m] = hold;
}
}
char[] buffer = pt.Replace(" ", string.Empty).ToCharArray();
int stringRemovedSpaces = pt.Length;
char[] buffer = pt.ToCharArray(); // source
char[] buffer2 = new char[ptLenght]; // destination
for (int i = 0; i < pt.Length; i++)
{
buffer2[i] = buffer[i];
}
for (int i = 0; i < buffer2.Length; i++)
{
if (i == spaceHolder[i])
{
for (int m = stringRemovedSpaces; m <= i; m--)
{
buffer2[m-1] = buffer2[m];
}
buffer2[i] = ' ';
}
}
return new string(buffer2);

I suspect that you want to replace multiple spaces with a single one. The fastest and easiest way to do this is with a simple regular expression that replaces multiple whitespaces with a single space, eg:
var newString = Regex.Replace("A B C",#"\s+"," ")
or
var newString = Regex.Replace("A B C",#"[ ]+"," ")
The reason this is fastest than other methods like repeated string replacements is that a regular expression does not generate temporary strings. Internatlly it generates a list of indexes to matching items. A string is generated only when the code asks for a string value, like a match or replacement.
A regular expression object is thread-safe as well. You can create it once, store it in a static field and reuse it :
static Regex _spacer = new Regex(#"\s+");
public void MyMethod(string someInput)
{
...
var newString=_spacer.Replace(someInput, " ");
...
}

Deleting all the spaces in a string is really just as simple as calling the Replace function on a string. Please note that when you call Replace on a string, it does not modify the original string, it creates and returns a new string. I only bring this up because you set two different integer variables to pt.Length, and at no point is the string pt actually modified. Also, I would imagine you are getting the "Index was outside of array bounds" from the nested for loop. You have the loop set up in a way that m will decrement forever. However, once m equals zero, you will be trying to access an index of -1 from buffer2, which is a no no. If you want to delete the spaces while retaining an original copy of the string you could simplify your code to this:
string pt = "My name is Code";
string newpt = pt.Replace(" ", string.empty);
pt is a string with spaces, newpt is a new string with spaces removed. However, if you want to replace multiple consecutive spaces with a single space, I would recommend following the answer Panagiotis Kanavos gave.

I followed the advice of #maccettura and I did it like this and it worked as I wished :)
string orignalString = "";
orignalString = pt;
char[] buffer = pt.ToCharArray();
orignalString = new string(buffer);
return orignalString.Replace(" ", string.Empty);
// Here I got the string without spaces , now I have the same string with and without spaces

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# replace different characters in a string

Everyone knows how to replace a character in a string with:
string text = "Hello World!";
text = text.Replace("H","J");
but what I need is to replace multiple characters in a string
something like:
string text = textBox1.Text;
text = text.Replace("a","b")
text = text.Replace("b","a")
now the result is aa , but if the user types ab I want the result to be ba

There's multiple ways to do this.
Using a loop
char[] temp = input.ToCharArray();
for (int index = 0; index < temp.Length; index++)
switch (temp[index])
{
case 'a':
temp[index] = 'b';
break;
case 'b':
temp[index] = 'a';
break;
}
string output = new string(temp);
This will simply copy the string to a character array, fix each character by itself, then convert the array back into a string. No risk of getting any of the characters confused with any of the others.
Using a regular expression
You can exploit this overload of Regex.Replace:
public static string Replace(
string input,
string pattern,
MatchEvaluator evaluator
)
This takes a delegate that will be called for each match, and return the final result. The delegate is responsible for returning what each match should be replaced with.
string output = Regex.Replace(input, ".", ma =>
{
if (ma.Value == "a")
return "b";
if (ma.Value == "b")
return "a";
return ma.Value;
});

For your particular requirement I would suggest you to use like the following:
string input = "abcba";
string outPut=String.Join("",input.ToCharArray()
.Select(x=> x=='a'? x='b':
(x=='b'?x='a':x))
.ToArray());
The output string will be bacab for this particular input

Do not call String.Replace multiple times for the same string! It creates a new string every time (also it has to cycle through the whole string every time) causing memory pressure and processor time waste if used a lot.
What you could do:
Create a new char array with the same length as the input string. Iterate over all chars of the input strings. For every char, check whether it should be replaced. If it should be replaced, write the replacement into the char array you created earlier, otherwise write the original char into that array. Then create a new string using that char array.
string inputString = "aabbccdd";
char[] chars = new char[inputString.Length];
for (int i = 0; i < inputString.Length; i++)
{
if (inputString[i] == 'a')
{
chars[i] = 'b';
}
else if (inputString[i] == 'b')
{
chars[i] = 'a';
}
else
{
chars[i] = inputString[i];
}
}
string outputString = new string(chars);
Consider using a switch when intending to replace a lot of different characters.

Use should use StringBuilder when you are concatenating many strings in a loop like this, so I suggest the following solution:
StringBuilder sb = new StringBuilder(text.Length);
foreach(char c in text)
{
sb.Append(c == 'a' ? 'b' : 'a');
}
var result = sb.ToString();

Iterating backwards through an char array after finding a known word

I've got a project I'm working on in C#. I've got two char array's. One is a sentence and one is a word. I've got to iterate through the sentence array until I find a word that matches the word that was turned into an word array what I'm wondering is once I find the word how do I iterate backwards through the sentence array at the point I found the word back through the same length as the word array?
Code :
String wordString = "(Four)";
String sentenceString = "Maybe the fowl of Uruguay repeaters (Four) will be found";
char[] wordArray = wordString.ToCharArray();
List<String> words = sentenceString.Split(' ').ToList<string>();
//This would be the part where I iterate through sentence
foreach (string sentence in sentArray)
{
//Here I would need to find where the string of (Four) and trim it and see if it equals the wordString.
if (sentence.Contains(wordString)
{
//At this point I would need to go back the length of wordString which happens to be four places but I'm not sure how to do this. And for each word I go back in the sentence I need to capture that in another string array.
}
I don't know if I'm being clear enough on this but if I'm not please feel free to ask.. Thank you in advanced. Also what this should return is "fowl of Uruguay repeaters". So basically the use case is for the number of letters in the parenthesis the logic should return the same number of words before the word in parenthesis.

our are you. I have few question concerned to this exercise.
If the Word (four) was in beginning it should not return? or return all string?
As the length of four is equal to 4 imagine if that word appear as the second word on sentence what it should return just the first word or return 4 words even including the (four) word.?
My solution is the laziest one I just see your question and decide to help.
My solution assumes it return all the word before the (four) if the length is bigger than the word before the (four) word.
My solution return empty string if the word (four) is in the beginning.
My solution return Length of (four) (4) words before (four) word.
ONCE AGAIN IT IS NOT MY BEST APPROACH.
I see the code bellow:
string wordString = "(Four)";
string sentenceString = "Maybe the fowl of Uruguay repeaters (Four) will be found";
//Additionally you can add splitoption to remove the empty word on split function bellow
//Just in case there are more space in sentence.
string[] splitedword = sentenceString.Split(' ');
int tempBackposition = 0;
int finalposition = 0;
for (int i = 0; i < splitedword.Length; i++)
{
if (splitedword[i].Contains(wordString))
{
finalposition = i;
break;
}
}
tempBackposition = finalposition - wordString.Replace("(","").Replace(")","").Length;
string output = "";
tempBackposition= tempBackposition<0?0:tempBackposition;
for (int i = tempBackposition; i < finalposition; i++)
{
output += splitedword[i] + " ";
}
Console.WriteLine(output);
Console.ReadLine();
If it's not what you want can you answer my questions on top? or help me to understand were it's wrong

int i ;
string outputString = (i=sentenceString.IndexOf(wordString))<0 ?
sentenceString : sentenceString.Substring(0,i) ;

var wordString = "(Four)";
int wordStringInt = 4; // Just do switch case to convert your string to int
var sentenceString = "Maybe the fowl of Uruguay repeaters (Four) will be found";
var sentenceStringArray = sentenceString.Split(' ').ToList();
int wordStringIndexInArray = sentenceStringArray.IndexOf(wordString) - 1;
var stringOutPut = "";
if (wordStringIndexInArray > 0 && wordStringIndexInArray > wordStringInt)
{
stringOutPut = "";
while (wordStringInt > 0)
{
stringOutPut = sentenceStringArray[wordStringInt] + " " + stringOutPut;
wordStringInt--;
}
}

What you are matching is kind of complex, so for a more general solution you could use regular expressions.
First we declare what we are searching for:
string word = "(Four)";
string sentence = "Maybe the fowl of Uruguay repeaters (Four) will be found";
We will then search for the words in this string using regular expressions. Since we don't want to match whitespace, and we need to know where each match actually starts and we need to know the word inside the parenthesis we tell it that we optionally want opening and ending parenthesis, but we also want the contents of those as a match:
var words = Regex.Matches(sentence, #"[\p{Ps}]*(?<Content>[\w]+)[\p{Pe}]*").Cast<Match>().ToList();
[\p{Ps}] means we want opening punctuation ([{ etc. while the * indicates zero or more.
Followed is a sub-capture called Content (specified by ?<Content>) with one or more word characters.
At the end we specify that we want zero or more ending punctuation.
We then need to find the word in the list of matches:
var item = words.Single(x => x.Value == word);
Then we need to find this item's index:
int index = words.IndexOf(item);
At this point we just need to know the length of the contents:
var length = item.Groups["Content"].Length;
This length we use to go back in the string 4 words
var start = words.Skip(index - length).First();
And now we have everything we need:
var result = sentence.Substring(start.Index, item.Index - start.Index);
Result should contain fowl of Uruguay repeaters.
edit: It may be a lot simpler to just figure out the count from the word rather than from the content. In that case the complete code should be the following:
string word = "(Four)";
string sentence = "Maybe the fowl of Uruguay repeaters (Four) will be found";
var wordMatch = Regex.Match(word, #"[\p{Ps}]*(?<Content>[\w]+)[\p{Pe}]*");
var length = wordMatch.Groups["Content"].Length;
var words = Regex.Matches(sentence, #"\S+").Cast<Match>().ToList();
var item = words.Single(x => x.Value == word);
int index = words.IndexOf(item);
var start = words.Skip(index - length).First();
var result = sentence.Substring(start.Index, item.Index - start.Index);
\S+ in this case means "match one or more non-whitespace character".

You should try something like the following, which uses Array.Copy after it finds the number word. You will still have to implement the ConvertToNum function correctly (it is hardcoded in for now), but this should be a quick and easy solution.
string[] GetWords()
{
string sentenceString = "Maybe the fowl of Uruguay repeaters (Four) will be found";
string[] words = sentenceString.Split();
int num = 0;
int i; // scope of i should remain outside the for loop
for (i = 0; i < words.Length; i++)
{
string word = words[i];
if (word.StartsWith("(") && word.EndsWith(")"))
{
num = ConvertToNum(word.Substring(1, word.Length - 1));
// converted the number word we found, so we break
break;
}
}
if (num == 0)
{
// no number word was found in the string - return empty array
return new string[0];
}
// do some extra checking if number word exceeds number of previous words
int startIndex = i - num;
// if it does - just start from index 0
startIndex = startIndex < 0 ? 0 : startIndex;
int length = i - startIndex;
string[] output = new string[length];
Array.Copy(words, startIndex, output, 0, length);
return output;
}
// Convert the number word to an integer
int ConvertToNum(string numberStr)
{
return 4; // you should implement this method correctly
}
See - Convert words (string) to Int, for help implementing the ConvertToNum solution. Obviously it could be simplified depending on the range of numbers you expect to deal with.

Here is my solution, im not using regex at all, for the sake of easy understanding:
static void Main() {
var wordString = "(Four)";
int wordStringLength = wordString.Replace("(","").Replace(")","").Length;
//4, because i'm assuming '(' and ')' doesn't count.
var sentenceString = "Maybe the fowl of Uruguay repeaters (Four) will be found";
//Transform into a list of words, ToList() to future use of IndexOf Method
var sentenceStringWords = sentenceString.Split(' ').ToList();
//Find the index of the word in the list of words
int wordIndex = sentenceStringWords.IndexOf(wordString);
//Get a subrange from the original list of words, going back x Times the legnth of word (in this case 4),
var wordsToConcat = sentenceStringWords.GetRange(wordIndex-wordStringLength, wordStringLength);
//Finally concat the output;
var outPut = string.Join(" ", wordsToConcat);
//Output: fowl of Uruguay repeaters
}

I have a solution for you:
string wordToMatch = "(Four)";
string sentence = "Maybe the fowl of Uruguay repeaters (Four) will be found";
if (sentence.Contains(wordToMatch))
{
int length = wordToMatch.Trim(new[] { '(', ')' }).Length;
int indexOfMatchedWord = sentence.IndexOf(wordToMatch);
string subString1 = sentence.Substring(0, indexOfMatchedWord);
string[] words = subString1.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
var reversed = words.Reverse().Take(length);
string result = string.Join(" ", reversed.Reverse());
Console.WriteLine(result);
Console.ReadLine();
}
Likely this can be improved regardng performance, but I have a feeling you don't care about that. Make sure you are using 'System.Linq'

I assumed empty returns when input is incomplete, feel free to correct me on that. Wasn't 100% clear in your post how this should be handled.
private string getPartialSentence(string sentence, string word)
{
if (string.IsNullOrEmpty(sentence) || string.IsNullOrEmpty(word))
return string.Empty;
int locationInSentence = sentence.IndexOf(word, StringComparison.Ordinal);
if (locationInSentence == -1)
return string.Empty;
string partialSentence = sentence.Substring(0, locationInSentence);
string[] words = partialSentence.Split(new[] {' '}, StringSplitOptions.RemoveEmptyEntries);
int nbWordsRequired = word.Replace("(", "").Replace(")", "").Length;
if (words.Count() >= nbWordsRequired)
return String.Join(" ", words.Skip(words.Count() - nbWordsRequired));
return String.Join(" ", words);
}

I went with using an enumeration and associated dictionary to pair the "(Four)" type strings with their integer values. You could just as easily (and maybe easier) go with a switch statement using
case "(Four)": { currentNumber = 4; };
I feel like the enum allows a little more flexibility though.
public enum NumberVerb
{
one = 1,
two = 2,
three = 3,
four = 4,
five = 5,
six = 6,
seven = 7,
eight = 8,
nine = 9,
ten = 10,
};
public static Dictionary<string, NumberVerb> m_Dictionary
{
get
{
Dictionary<string, NumberVerb> temp = new Dictionary<string, NumberVerb>();
temp.Add("(one)", NumberVerb.one);
temp.Add("(two)", NumberVerb.two);
temp.Add("(three)", NumberVerb.three);
temp.Add("(four)", NumberVerb.four);
temp.Add("(five)", NumberVerb.five);
temp.Add("(six)", NumberVerb.six);
temp.Add("(seven)", NumberVerb.seven);
temp.Add("(eight)", NumberVerb.eight);
temp.Add("(nine)", NumberVerb.nine);
temp.Add("(ten)", NumberVerb.ten);
return temp;
}
}
static void Main(string[] args)
{
string resultPhrase = "";
// Get the sentance that will be searched.
Console.WriteLine("Please enter the starting sentance:");
Console.WriteLine("(don't forget your keyword: ie '(Four)')");
string sentance = Console.ReadLine();
// Get the search word.
Console.WriteLine("Please enter the search keyword:");
string keyword = Console.ReadLine();
// Set the associated number of words to backwards-iterate.
int currentNumber = -1;
try
{
currentNumber = (int)m_Dictionary[keyword.ToLower()];
}
catch(KeyNotFoundException ex)
{
Console.WriteLine("The provided keyword was not found in the dictionary.");
}
// Search the sentance string for the keyword, and get the starting index.
Console.WriteLine("Searching for phrase...");
string[] words = sentance.Split(' ');
int searchResultIndex = -1;
for (int i = 0; (searchResultIndex == -1 && i < words.Length); i++)
{
if (words[i].Equals(keyword))
{
searchResultIndex = i;
}
}
// Handle the search results.
if (searchResultIndex == -1)
{
resultPhrase = "The keyword was not found.";
}
else if (searchResultIndex < currentNumber)
{
// Check the array boundaries with the given indexes.
resultPhrase = "Error: Out of bounds!";
}
else
{
// Get the preceding words.
for (int i = 0; i < currentNumber; i++)
{
resultPhrase = string.Format(" {0}{1}", words[searchResultIndex - 1 - i], resultPhrase);
}
}
// Display the preceding words.
Console.WriteLine(resultPhrase.Trim());
// Exit.
Console.ReadLine();
}

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;