How to use Regex to split a string AND include whitespace

Question

I can't seem to find (or write) a simple way of splitting the following sentence into words and assigning a word to the whitespace between the letters. (VS 2010, C#, .net4.0).

String text = "This is a test.";

Desired result: 
[0] = This
[1] = " "
[2] = is
[3] = " "
[4] = a
[5] = " "
[6] = test.

The closest I have come is:

  string[] words = Regex.Split(text, @"\s");

but ofcourse, this drops the whitespace.

Suggestions are appreciated. Thanks

Edit: There may be one or more spaces between the words. I would like all spaces between the words to be returned as a "word" itself (with all spaces being placed in that "word"). e.g., if 5 spaces between a word would be.

String spaceword = " "; <--This is not showing correctly, there should be a string of 5 spaces.

@AmitJoki no. there may be multiple spaces between words. Thanks — Alan Wayne, Jan 24 '15 at 17:51
@AlanWayne then what should be the result? do you wanna remove additional spaces? — Selman Genç, Jan 24 '15 at 17:51
[Relevant answer](http://stackoverflow.com/questions/15667927/how-to-keep-the-delimiters-of-regex-split) — Kilazur, Jan 24 '15 at 17:57

score 2 · Answer 1 · answered Jan 24 '15 at 17:50

2

You can use LINQ to add spaces manually between them:

var parts = text.Split(new[]{ ' ' }, StringSplitOptions.RemoveEmptyEntries);
var result = parts.SelectMany((x,idx) => idx != parts.Length - 1 
                                         ? new[] { x, " " }
                                         : new[] { x }).ToList();

answered Jan 24 '15 at 17:50

Selman Genç

100,147
13
119
184

And the Regex would be? – Alan Wayne Jan 24 '15 at 17:52
The question asks specifically for a Regex, then, however useful, your answer doesn't suit it. – Kilazur Jan 24 '15 at 17:54
@Kilazur that's not how it works. That's not how any of SO works. – Amit Joki Jan 24 '15 at 17:55
1

@Kilazur As long as the answer solves the OP's problem, you're allowed to post any solution/workarround you think it's better to be used – Enissay Jan 24 '15 at 17:59
@Selman22 Yep. It works! How could this be done using Regex? Thanks. – Alan Wayne Jan 24 '15 at 18:15
@AlanWayne - Regex isn't always necessary or the best way to do string manipulation. If this works then you don't need a regex – ChrisF Jan 24 '15 at 18:19
@ChrisF Very true. Trying to understand regex a better. – Alan Wayne Jan 24 '15 at 18:23

score 2 · Accepted Answer · answered Jan 24 '15 at 18:02

2

Change your pattern to (\s+):

        String text = "This        is a   test.";
        string[] words = Regex.Split(text, @"(\s+)");
        for(int i =0; i < words.Length;i++)
        {
            Console.WriteLine(i.ToString() + "," + words[i].Length.ToString() + " = " + words[i]);
        }

Here's the output:

0,4 = This
1,8 =         
2,2 = is
3,1 =  
4,1 = a
5,3 =    
6,5 = test.

answered Jan 24 '15 at 18:02

Idle_Mind

38,363
3
29
40

I tried earlier, this dropped the white space between words. – Alan Wayne Jan 24 '15 at 18:03
Try my specific example, and take a look at the output in the edit above. If you are getting different results, please update us with specifics. – Idle_Mind Jan 24 '15 at 18:05
That's it. How did adding the (...) make the difference? Thanks. – Alan Wayne Jan 24 '15 at 18:29
1

The parenthesis make it a [captured group](http://www.regular-expressions.info/brackets.html), which means it will be kept: "Besides grouping part of a regular expression together, parentheses also create a numbered capturing group. It stores the part of the string matched by the part of the regular expression inside the parentheses." – Idle_Mind Jan 24 '15 at 18:31
It's also [here](https://msdn.microsoft.com/en-us/library/8yttk7sy(v=vs.110).aspx) in the MSDN for Regex.Split(): "If capturing parentheses are used in a Regex.Split expression, any captured text is included in the resulting string array." – Idle_Mind Jan 24 '15 at 18:36

Amit Joki · Answer 3 · 2015-01-25T07:38:26.853

1

You can try this regex, \w+|\s+ which uses or operator |

var arr = Regex.Matches(text, @"\S+|\s+").Cast<Match>()
                                         .Select(i => i.Value)
                                         .ToArray();

It just matches both words and spaces and some LINQ stuff is being used so arr is just a String Array

edited Jan 25 '15 at 07:38

answered Jan 24 '15 at 17:56

Amit Joki

58,320
7
77
95

so...don't use Regex.Split? – Alan Wayne Jan 24 '15 at 18:02
This is almost perfect.. One problem, the words may contain a "/", i.e., a word could be "w/o". The above regex splits the word on the "/" character. Ideas?? – Alan Wayne Jan 24 '15 at 18:08

How to use Regex to split a string AND include whitespace

3 Answers3