how to count Enter in a string?

Question

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How would you count occurences of a string within a string (C#)?

I have a string that has multiple sub-strings and Enter (special character by pressing Enter key) between them.

Can you please guide me how to write a regular expression that counts Enter keys between words ?

Thanks

Why do you need a _regular expression_ for counting the number of occurrences of a character in a string? That's overkill. Just count the characters some other way. Iterate through the characters. Or perhaps there is a library function. — Ray Toal, Dec 13 '12 at 03:25
Would the "Enter"s be `"\r\n"` (`CRLF`), `"\n"` (`LF`) or `"\r"` (`CR`)? — Alvin Wong, Dec 13 '12 at 03:26
"Hey, I have a problem that is related to strings. I must need a regex." — ean5533, Dec 13 '12 at 03:26
Lots of ways here: http://stackoverflow.com/questions/541954/how-would-you-count-occurences-of-a-string-within-a-string-c — ean5533, Dec 13 '12 at 03:28

score 9 · Accepted Answer · answered Dec 13 '12 at 03:28

9

Depending on the line break symbol used you may have to change to just \r or just \n.

var numberLineBreaks = Regex.Matches(input, @"\r\n").Count;

answered Dec 13 '12 at 03:28

Daniel Brückner

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thanks, it works for me. I really need of this. – Jul 24 '18 at 09:11

score 7 · Answer 2 · edited May 23 '17 at 10:28

7

You don't need a regex, you're just counting strings. Specifically you're just counting Environment.Newlines. There's lots of ways to do that; several are described in this SO answer. Here's one which looks inefficient but performs surprisingly well:

int count1 = source.Length - source.Replace(Environment.Newline, "").Length;

edited May 23 '17 at 10:28

Community

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answered Dec 13 '12 at 03:32

ean5533

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score 3 · Answer 3 · answered Dec 13 '12 at 03:26

3

Does it have to be a regular expression? There are probably easier ways... for example, you could use string[] array = String.Split('\n'); to create an array of the substrings, then get the count with array.Length;

answered Dec 13 '12 at 03:26

Tim Long

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1

You probably need to subtract one from the result. – Alvin Wong Dec 13 '12 at 03:27
This would be extremely inefficient and wasteful, since the OP only need a count. – Zar Shardan Dec 13 '12 at 03:55

neeKo · Answer 4 · 2012-12-13T04:51:52.090

0

You could do by simply counting the newlines:

int start = -1;
int count = 0;
while ((start = text.IndexOf(Environment.NewLine, start + 1)) != -1)
    count++;
return count;

edited Dec 13 '12 at 04:51

answered Dec 13 '12 at 03:28

neeKo

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score 0 · Answer 5 · answered Dec 13 '12 at 03:44

You can use this Code,

using System;
using System.Text.RegularExpressions;

class Program
    {
        static void Main()
        {
         long a = CountLinesInString("This is an\r\nawesome website.");
         Console.WriteLine(a);

         long b = CountLinesInStringSlow("This is an awesome\r\nwebsite.\r\nYeah.");
         Console.WriteLine(b);
         }

         static long CountLinesInString(string s)
         {
          long count = 1;
          int start = 0;
          while ((start = s.IndexOf('\n', start)) != -1)
          {
              count++;
               start++;
          } 
          return count;
         }

         static long CountLinesInStringSlow(string s)
         {
          Regex r = new Regex("\n", RegexOptions.Multiline);
          MatchCollection mc = r.Matches(s);
          return mc.Count + 1;
         }
 }

how to count Enter in a string?

5 Answers5