Group Specific Lines of a TextBox into a String

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hey guys,

I am now starting on working with textboxes and I want to be able to group specific lines of a textbox into 1 string. I don't know even if this is possible, but I want to try. This is an example textbox code:

group (groupname)
     (text goes here)
end group

I want to be able to group the text between the group name into a string. Do you know how to do this? Please help!

Posted 29-May-12 11:48am

Member 8378691

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Sergey Alexandrovich Kryukov 29-May-12 18:43pm

What's the problem? And you did not specify how exactly groups are defined or recognized, what's the expected result.
You can use "Improve question" above, add descriptive examples if ins and outs, etc.
--SA

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OriginalGriff · Accepted Answer · 2012-05-29T20:39:00

Solution 1

If you mean that you want to get the text from a mutliline TextBox, and extract any text between an Start-of-group indicator and an End-of-group indictor, then it's pretty simple - just use a Regex:

C#

public static Regex regex = new Regex(
      "(?<=group \\()(?<GroupName>.*?)\\)(?<Data>.*?)(?=end group)",
    RegexOptions.Singleline
    | RegexOptions.CultureInvariant
    | RegexOptions.Compiled
    );
private void myButton_Click(object sender, EventArgs e)
    {
    // Capture all Matches in the InputText
    MatchCollection ms = regex.Matches(textBox1.Text);
    foreach (Match m in ms)
        {
        Console.WriteLine("{0} = \"{1}\"", m.Groups["GroupName"], m.Groups["Data"]);
        }
    }

"could you please explain this code to me? I am not very good with regex. I do not use it very much, and all the times i do use it, i just copy code from the internet"

Firstly, get a copy of Expresso[^] - it's free, and it examines and generates Regular expressions. it can explain then to you as well as help you create them.
Used correctly, Regexes are a wonderful tool!

Here is what it says about the above:
///
/// Regular expression built for C# on: Wed, May 30, 2012, 10:20:39 AM
/// Using Expresso Version: 3.0.3634, http://www.ultrapico.com
///
/// A description of the regular expression:
///
/// Match a prefix but exclude it from the capture. [group \(]
/// group \(
/// group
/// Space
/// Literal (
/// [GroupName]: A named capture group. [.*?]
/// Any character, any number of repetitions, as few as possible
/// Literal )
/// [Data]: A named capture group. [.*?]
/// Any character, any number of repetitions, as few as possible
/// Match a suffix but exclude it from the capture. [end group]
/// end group
/// end
/// Space
/// group
///
What that means is that the regex is made up of 5 sections:

(?<=group \()

A prefix which is required, but not captured: "group ("

(?<GroupName>.*?)

Variable data which is captured as a data group called "GroupName", which consists of all characters up to the next section.

\)

A ")" to terminate the group name

(?<Data>.*?)

Variable data which is captured as a data group called "Data", which consists of all characters up to the next section.

(?=end group)

A suffix which is required, but not captured: "end group"

So what it does is look for text which starts with "group (xxx)" and ends with "end group" and stores the "xxx" as a name, and the rest as data.

All the C# code is doing is declaring the regex, and telling it to capture all matching data. It then loops though each set of matches and prints out the group name with it's related data.

Sorted!

Posted 29-May-12 20:39pm

OriginalGriff

Updated 29-May-12 23:29pm

v2

Comments

Member 8378691 30-May-12 5:13am

could you please explain this code to me? I am not very good with regex. I do not use it very much, and all the times i do use it, i just copy code from the internet

Member 8378691 1-Jun-12 3:10am

this isn't exactly what i was looking for...it is still good, but i want to store the data as a string. so lets say something like:

string 'something' = *this is where the Regex is used, this is the data stored between 'group(xxx)' and 'end group'*

OriginalGriff 1-Jun-12 3:49am

If you only have the one, then change the regex slightly to discard the group name and just use the single value:
public static Regex regex = new Regex(
"(?<=group \\(.*?\\))(?.*?)(?=end group)",
RegexOptions.Singleline
| RegexOptions.CultureInvariant
| RegexOptions.Compiled
);
...
string s = regex.Match(textBox1.Text).Value;

Member 8378691 1-Jun-12 18:36pm

I need to have more than just one group though. am I allowed to do something like:

public static Regex regex = new Regex(
"(?<=group " & stringname & " \\(.*?\\))(?.*?)(?=end group)",
RegexOptions.Singleline
| RegexOptions.CultureInvariant
| RegexOptions.Compiled );
...
string s = regex.Match(textBox1.Text).Value;

that is what I am looking for, but I don't know if that will work.

Member 8378691 2-Jun-12 0:42am

hey,

I just tried out the code and i realised that this is in C#, i am programming this in Visual Basic

OriginalGriff 2-Jun-12 3:54am

Pretty much, yes - you would have to move teh regex to a local variable, and removed the Compiled option (and covert the code to VB which is pretty trivial) The only difference is that you need to put the group name inside your "(" and ")" characters, not outside as you have done, and you can then get rid of the ".*?" part which matches any name. Seriously - get a copy of Expresso, it can even generate the VB code for you!

Member 8378691 2-Jun-12 4:57am

hey, i have run this code:

Dim regex As Regex = New Regex(
"(?<=group \(" & classname & "\))(?)(?=end group)",
RegexOptions.Singleline Or RegexOptions.CultureInvariant)

(classname = start)

and this is the error that I got:

parsing "(?<=group \(start\))(?)(?=end group)" - Quantifier

can you please change my code or tell me how to fix this/

OriginalGriff 2-Jun-12 5:13am

Take the "(?)" bit out...
Download Expresso - it will tell you these things and save you a lot of time asking me, and waiting for a response! :laugh:

Member 8378691 2-Jun-12 5:41am

this works! you are just awesome! i don't know how you do this.

OriginalGriff 2-Jun-12 5:47am

Practice! :laugh:

Member 8378691 3-Jun-12 0:00am

actually, i used it a bit more and i wanted to use it for my programming language for classes but i found that it doesn't work. I would type this in:

group (start)
print Hello World
end group
print Something

and it would print both Hello World and Something. this is my code:

Dim regex As Regex = New Regex( "(?<=group \(" & classname & "\))(?)(?=end group)", RegexOptions.Singleline Or RegexOptions.CultureInvariant)

string code = regex.match(textbox1.text).Value

for each a as string in code.split(controlchars.lf)
if a.startswith("print ")
textbox2.text &= a.substring(6)
end if
next

can you please fix up my code?

OriginalGriff 3-Jun-12 3:36am

That isn't your code.
That won't compile, and will throw a regex format error!

Member 8378691 3-Jun-12 5:15am

can you just please fix it?

OriginalGriff 3-Jun-12 5:34am

:laugh: How?
It doesn't compile, so it doesn't do what you say it does - so it's difficult to fix the code you do have, that does do what you say it does, but that I can't see!

Member 8378691 4-Jun-12 2:50am

is there another way that I can add classes to my programming language? please help.

OriginalGriff 4-Jun-12 3:02am

You are trying to write a new language and process it? Impressive - that's a big job!
Personally, I wouldn't start like this at all: I would tokenise the input into an internal representation first (google can help with that) but I am willing to admit I haven't looked a compiler/interpreter writing techniques for thirty years so I could be rather out of date! :laugh:

So the simple answer would have to be: dunno - it is going to depend far, far too much on the rest of your system and how that works.

Member 8378691 5-Jun-12 4:17am

i have tokenised my programming language. i have assigned it into a list called tokens and then the parser looks at each individual tokens and does what is assigned to that token. if the token is not recognised, then an error is passed. I have done programming languages before, but i don't know how to add classes. i thought that the easiest way for me was to do something like this, it takes the code from inbetween 2 strings and put it into another string.