How do I do greater than and less than in the same command then find the size?

I need to find the number of values that fall between two values, i.e. number of seisms that were between 7 and 8 magnitude, out of 11655 total values. size(7<=mag<=8)

Answer 1

[Matt J]

sum(7<=mag & mag<=8)

[Lora Priest Dutheil]

It gave me an answer that I can't check is correct. It didn't add (sum) the values but gave me the number (size) of values that were in the parameters, right?

Answer 2

[Roger Stafford]

This is very elementary matlab. Assuming 'mag' is a vector, do this:

   count = sum((7<=mag)&(mag<=8));

[Lora Priest Dutheil]

Sorry, your answer didn't work but the other one did. It probably is elementary but I couldn't find the answer anywhere in Help.

[Star Strider]

How could they give different results? They’re both the same code!

[Lora Priest Dutheil]

No idea, I'm far from an expert. All I know is that this code gave me an error message.

[Roger Stafford]

@Lora: It takes ingenuity to make an innocuous line like

count = sum((7<=mag)&(mag<=8));

give rise to an error message. Let me think of the ways.

1) An incomplete copy leading to unbalanced parentheses;
2) Naming a variable 'sum';
3) Failing to evaluate 'mag' in advance;
4) Having 'mag' be non-numeric and incomparable with numbers.

What exactly did your error message state, and did it actually refer to the above line?

[Lora Priest Dutheil]

Was replying from memory. Re-did it and it doesn't give me an error message, it's just blank, no result. And 'mag' is a numeric variable of earthquake magnitude with 11,655 data points. Thank you for trying to help the newbie with no experience in this kind of thing whatsoever and who, once this class is finished, will probably never, ever use Matlab again.