String split using C#

Question

I have the following string:

string text = "1. This is first sentence. 2. This is the second sentence. 3. This is the third sentence. 4. This is the fourth sentence."

I want to split it according to 1. 2. 3. and so on:

result[0] == "This is first sentence."
result[1] == "This is the second sentence."
result[2] == "This is the third sentence."
result[3] == "This is the fourth sentence."

Is there any way I can do it C#?

• Emond: Please explain: "because it is not that way."
• sll: How you would like split following 1. First line 2. Second Numbered2. 2. Third Line
• Joel Coehoorn: I think he means that a sentence might spill onto another line. Hopefully sentences do at least still end in line breaks, in which case what we're really looking for is lines that start with digits followed by a period and a space. But I want to see that confirmed before I provide an answer, and I also want to know whether or not he wants to keep the sentence number.
• Yatrix: Are they separated by carriage returns or is there the potential for it being "1. This is first sentence.2. This is the second sentence.3. This is the third sentence." you could possibly separate it out using regular expressions checking for digits followed by decimals, but that would break if "3." was in the middle of a sentence.
• fawad: I have updated my question again.

Answer 1

Assuming that you can't encounter such a pattern in your sentences : X. (a integer, followed by a point, followed by a space), this should work:

String[] result = Regex.Split(text, @"[0-9]+\. ");

• Zann Anderson: Or you could use @"\d+\. " as your pattern, where \d is the shortcut for matching a digit.
• Otiel: @Zannjaminderson: That's not actually true: \d matches any unicode digit (fileformat.info/info/unicode/category/Nd/list.htm). For instance, this character ௮ will be splitted if you use \d but won't be if you use [0-9].
• Zann Anderson: Thanks for the clarification - that's an interesting point - not sure it's going to be a problem in this case, but it's worth understanding for sure.
• Otiel: @Zannjaminderson: I agree that those "special" characters (meaning not the arabics digits we are used to) are (to say the least) quite rare. But that's a shame that all regex cheat sheets are indicating that \d is equivalent to [0-9]. :)
• Zann Anderson: Agreed, thank you for shedding some light on that. Curse you lying regex cheat sheets! That would certainly make \d a rather leaky abstraction if you started to run into cases where your regex was matching special characters you hadn't intended it to match...

Answer 2

is it possible that there will be numbers in the sentence too?

As I do not know you formatting, you already said you cannot do on EOL/New Line I would try something like...

List<string> lines = new List<string>();
string buffer = "";
int count = 1;
foreach(char c in input)
{
 if(c.ToString() == count.ToString())
 {
 if(!string.IsNullOrEmpty(buffer))
 {
 lines.Add(buffer);
 buffer = "";
 }
 count++;
 }
 buffer += c;
}
//lines will now contain your splitted data

You can then access each sentence like this...

string s1 = lines[0];
string s2 = lines[1];
string s3 = lines[2];

Important: Make sure you check the count of lines before getting sentence like...

string s1 = lines.Count > 0 ? lines[0] : "";

This makes a big assumption that you will not have the next lines number ID in a given sentance (i.e. sentence 2 will not contain the number 3)

If this does not help the provide you input in original format (do not add lines breaks if there are none)

EDIT: Fixed my code (wrong variable sorry)

• fawad: Dear, i'm not able to understand your logic. All i want is something like: string1 = 1. This is first sentence, string2 = 2. This is second sentence and so on.
• musefan: @fawad, see edit for how you can access each sentence after the function

Answer 3

int index = 1; 
String[] result = Regex.Split(text, @"[0-9]+\. ").Where(i => !string.IsNullOrEmpty(i)).Select(i => (index++).ToString() + ". " + i).ToArray();

result will contain your sentences, including the "line number".

Answer 4

You could split on the '.' char and drop anything smaller than 2 char from the resulting array.

Of course, this relies on the fact that you would have no datapoints of 1 character other than the numeric indicator, if that was the case you could also check for it as a numeric value.

This answer would also drop a period from your sentences, so you'd have to add that back in. There is a lot of manipulation but this saves you from having to read each char and decision it independently.

Answer 5

This is the easiest way:

 var str = "1. This is first sentence." +
 "2. This is the second sentence." +
 "3. This is the third sentence." +
 "n. This is the nenth sentence";
 //set your max number e.g 10000
 var num = Enumerable.Range(1, 10000).Select(x=>x.ToString()+".").ToArray(); 
 var res=str.Split(num ,StringSplitOptions.RemoveEmptyEntries);

Hope this help ;)

• Sedat Kapanoglu: I don't always create an array but when I do I create it with at least 10000 items.