Count Values in a Matrix

Forum|Forum|9 years ago
September 13, 2016
4 replies
7613 views

Hello,

I'm new to MathCAD and may have missed something obvious, but is it possible to count particular values in a matrix? For example, counting how many times the number "18" occurs in a 1 x 5 matrix.

Thanks,

Adrian

Other

Best answer by RichardJ

It's not only possible, it's very easy;

R

RichardJ

Answer

19-Tanzanite

It's not only possible, it's very easy;

A

acharest

Author

1-Visitor

But if the value isn't present MathCAD returns an error. Sorry for not being clear, is there a way to return "0" if the value is not there?

R

RichardJ

19-Tanzanite

No problem:

The "on error" statement is from the programming toolbar, you can't just type it.

1_MatchCount-xmcdz.zip

L

LucMeekes

23-Emerald IV

There are more roads that lead to Rome...

Hist will count the number of elements of its second argument (M in this case), that are within the intervals as described by its first argument (the vector with elements 0 through 9, note that 0.5 is added to each element of this vector).

From the help:

hist(intvls,data) Returns a histogram of data - a vector representing the frequencies with which values in data fall into the intervals represented by intvls.

Note that this method will count 1.1 as well as 0.9 in the bin for 1's, like wise for the other numbers.

Success!
Luc

L

LucMeekes

23-Emerald IV

And then there's this:

histogram(intvls,data) Returns a matrix with two columns. The first column contains midpoints of the n subintervals of the range min(A) <= value <= max(A) of equal length. The second column is identical to hist(n, A), and hence the resulting matrix has n rows. Using histogram rather than hist saves you the additional step of defining horizontal axis data when plotting.

Luc

M

MartinHanak