How can I split and trim a string into parts all on one line?

Question

I want to split this line:

string line = "First Name ; string ; firstName";

into an array of their trimmed versions:

"First Name"
"string"
"firstName"

How can I do this all on one line? The following gives me an error "cannot convert type void":

List<string> parts = line.Split(';').ToList().ForEach(p => p.Trim());

The error is returned because `ForEach` works on current instance of `IEnumerable` and returns `void`. — Majkel, Nov 13 '09 at 10:13

score 378 · Accepted Answer · edited Dec 22 '22 at 09:49

378

Try

List<string> parts = line.Split(';').Select(p => p.Trim()).ToList();

FYI, the Foreach method takes an Action (takes T and returns void) for parameter, and your lambda return a string as string.Trim return a string

Foreach extension method is meant to modify the state of objects within the collection. As string are immutable, this would have no effect

edited Dec 22 '22 at 09:49

starball

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answered Nov 13 '09 at 10:10

Cédric Rup

15,468
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4

Note: `ForEach` is not an extension method. – Guffa Mar 15 '12 at 23:52
Best solution in Linq! – Sonhja Apr 22 '16 at 13:55
What if there are no values does it return null? – Demodave Jan 27 '20 at 14:06
if line is null then you get an exception. if line does not contain ';' you'll have a list with one string corresponding to the trimmid line – Cédric Rup Jan 28 '20 at 13:30

Guffa · Answer 2 · 2012-05-25T10:59:11.577

27

The ForEach method doesn't return anything, so you can't assign that to a variable.

Use the Select extension method instead:

List<string> parts = line.Split(';').Select(p => p.Trim()).ToList();

edited May 25 '12 at 10:59

answered Nov 13 '09 at 10:11

Guffa

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Gui Ferreira · Answer 3 · 2023-03-22T16:34:00.733

20

After .net 5, the solution is as simple as:

string[] parts = line.Split(';', StringSplitOptions.TrimEntries);

edited Mar 22 '23 at 16:34

answered Nov 22 '21 at 22:05

Gui Ferreira

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YES!!!!!!!!!!!!!!!!!! Finally!!!!! (cue CeCe Peniston: https://www.youtube.com/watch?v=xk8mm1Qmt-Y ) – Pure.Krome Nov 28 '21 at 13:37
Needs a `.ToList()` at the end. – secondplace Mar 21 '23 at 15:36

score 6 · Answer 4 · answered Nov 13 '09 at 10:11

6

Because p.Trim() returns a new string.

You need to use:

List<string> parts = line.Split(';').Select(p => p.Trim()).ToList();

answered Nov 13 '09 at 10:11

Matt Breckon

3,374
20
26

score 4 · Answer 5 · answered May 29 '15 at 15:34

Here's an extension method...

    public static string[] SplitAndTrim(this string text, char separator)
    {
        if (string.IsNullOrWhiteSpace(text))
        {
            return null;
        }

        return text.Split(separator).Select(t => t.Trim()).ToArray();
    }

score 2 · Answer 6 · answered Jul 24 '13 at 09:08

2

Alternatively try this:

string[] parts = Regex.Split(line, "\\s*;\\s*");

answered Jul 24 '13 at 09:08

Lawrence Phillips

289
1
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12

This is a great idea, however, I believe that misses any trailing blanks at the end of the string, correct? – jrichview Jun 01 '17 at 18:13

score 2 · Answer 7 · answered Jul 07 '15 at 10:58

2

try using Regex :

List<string> parts = System.Text.RegularExpressions.Regex.Split(line, @"\s*;\s*").ToList();

answered Jul 07 '15 at 10:58

user2826608

29
1

score 0 · Answer 8 · edited Nov 17 '19 at 17:54

Split returns string[] type. Write an extension method:

public static string[] SplitTrim(this string data, char arg)
{
    string[] ar = data.Split(arg);
    for (int i = 0; i < ar.Length; i++)
    {
        ar[i] = ar[i].Trim();
    }
    return ar;
}

I liked your solution so I decided to add to it and make it more usable.

public static string[] SplitAndTrim(this string data, char[] arg)
{
    return SplitAndTrim(data, arg, StringSplitOptions.None);
}

public static string[] SplitAndTrim(this string data, char[] arg, 
StringSplitOptions sso)
{
    string[] ar = data.Split(arg, sso);
    for (int i = 0; i < ar.Length; i++)
        ar[i] = ar[i].Trim();
    return ar;
}

score -1 · Answer 9 · answered Dec 21 '16 at 01:50

Use Regex

string a="bob, jon,man; francis;luke; lee bob";
   String pattern = @"[,;\s]";
            String[] elements = Regex.Split(a, pattern).Where(item=>!String.IsNullOrEmpty(item)).Select(item=>item.Trim()).ToArray();;   
            foreach (string item in elements){
                Console.WriteLine(item.Trim());

Result:

bob

jon

man

francis

luke

lee

bob

Explain pattern [,;\s]: Match one occurrence of either the , ; or space character

How can I split and trim a string into parts all on one line?

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