How do I access an element in an answer array directly?

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Kishore
Kishore am 24 Apr. 2025
Kommentiert: Stephen23 am 28 Apr. 2025
I have a variable named snsr_type as defined below. I want extract just "Diff" and store it in snsr_type variable. I have to do this in 2 steps.
snsr_name = "Diff sensor A1";
snsr_type = split(snsr_name,' ');
snsr_type = snsr_type(1);
If I combine those last 2 lines like this, it errors out saying "Error: Invalid array indexing.". I've also tried wrapping the first part in () like (split(snsr_name,' '))(1). This also doesn't work.
snsr_type = split(snsr_name,' ')(1);
Is there any way of doing this simply in a single line? Or do I have to do this in 2 lines?
  6 Kommentare
Image Analyst
Image Analyst am 26 Apr. 2025
snsr_name = "Diff sensor A1";
snsr_type = extractBefore(snsr_name,' ') % Get first word, which is the sensor type
snsr_type = "Diff"
Kishore
Kishore am 28 Apr. 2025
Thanks @Paul Lambrechts and @Image Analyst. I think the extractbefore function will work in this very specific case. This question was more about accessing specific elements of an array directly in the same line as the (answer) array is being created. I do not think the extractbefore function is capable of that (for ex., what if my answer array is numeric).
Therefore, I think the solution for my question is still that it needs to be done in 2 steps as @Image Analyst answered earlier. Thanks for your help!

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Akzeptierte Antwort

Image Analyst
Image Analyst am 24 Apr. 2025
Evidently you need to do it in two steps. A bonus though is that the two step method is much more readable and understandable. I think the single line way would be more confusing - a head scratcher for most people.

Weitere Antworten (1)

Walter Roberson
Walter Roberson am 28 Apr. 2025
Two approaches:
First = @(V) V(1);
snsr_name = "Diff sensor A1";
snsr_type1 = First(split(snsr_name,' '))
snsr_type1 = "Diff"
snsr_type2 = struct('Data', split(snsr_name,' ')).Data(1)
snsr_type2 = "Diff"
  2 Kommentare
Steven Lord
Steven Lord am 28 Apr. 2025
A third (somewhat complicated) way:
snsr_name = "Diff sensor A1";
y = subsref(split(snsr_name, ' '), substruct('()', {1}))
y = "Diff"
Stephen23
Stephen23 am 28 Apr. 2025
The simplest approach is likely to be faster in many situations:
timeit(@f0)
ans = 6.7571e-07
timeit(@f1)
ans = 2.3588e-06
timeit(@f2)
ans = 4.9818e-06
timeit(@f3)
ans = 8.9755e-06
function f0()
snsr_name = "Diff sensor A1";
snsr_type = split(snsr_name,' ');
snsr_type = snsr_type(1);
end
function f1()
First = @(V) V(1);
snsr_name = "Diff sensor A1";
snsr_type = First(split(snsr_name,' '));
end
function f2()
snsr_name = "Diff sensor A1";
snsr_type = struct('Data', split(snsr_name,' ')).Data(1);
end
function f3()
snsr_name = "Diff sensor A1";
snsr_type = subsref(split(snsr_name, ' '), substruct('()', {1}));
end

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