append (not strcat) to combine strings with whitespace (\n)
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Gavin
on 1 Aug 2024 at 3:38
Answered: Walter Roberson
on 6 Aug 2024 at 20:59
I have a text box (text edit field, shoud it be a label box?)
I want to add lines of text to it without loosing the old text.
app.DebugField.Value = append(app.DebugField.Value, "rew LB\n");
but the newlines are showing up as text \n
Start Trials at 22:26:09 >> rew LB\n
I guess I have to sprintf() the string first but why can't \n be properly interpreted by string handling functions?
3 Comments
Stephen23
on 1 Aug 2024 at 4:10
Edited: Stephen23
on 1 Aug 2024 at 5:10
"I guess I have to sprintf() the string first but why can't \n be properly interpreted by string handling functions?"
Only the functions which are documented to interpret such special characters (e.g. SPRINTF, FPRINTF, COMPOSE, etc.) will interpret such escaped sequences. Text operations such as concatenation do not interpret anything.
"... even sprintf() to magically turn \n into hex13 hex 10 isn't working!"
Note that carriage return is actually decimal 13 (hex: D) and line feed is decimal 10 (hex: A).
If you want a carriage return followed by a line feed then you can specify this:
txt = sprintf('%s\r\n','hello','world')
double(txt) % check that char(13) and char(10) have been created
Voss advised that an EDIT FIELD is for a single line of text. Use a TEXT AREA if you want to display multiple lines:
Accepted Answer
SACHIN KHANDELWAL
on 1 Aug 2024 at 4:10
I had a quick look into the code and found that the "append" function only takes strings as input and concatenates them. It will not evaluate expressions like "\n".
Therefore, I would recommend trying a different workflow. Here is one that I think might be helpful to you. Please refer to the following MATLAB code:
newText = 'rew LB';
app.TextArea.Value = [app.TextArea.Value; newText]; % This way you can append text in the new line
Hope it helps!
More Answers (2)
Voss
on 1 Aug 2024 at 4:35
From here:
"If you want to allow multiple lines of text, use a text area component instead of an edit field."
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Walter Roberson
on 6 Aug 2024 at 20:59
app.DebugField.Value = append(app.DebugField.Value, "rew LB" + newline);
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