How can I create a list of ranges and tell the program to verify in which range is my number and pick the inferior limit?

Hi, I have a quite simple question but It's difficult to me to translate that in Matlab code. I have a vector of numbers like a= [1,3,6,12,24,35] and a list of ranges that I divided in two vectors with all the inferior limits and the superior limits like: inf=[0,5,10,15,20,25,30] and sup=[5,10,15,20,25,30].

My goal it to verify in which range stays a number of the vector a and to create a vector of the inf limits of the range.

For example: first number =1, it stays in the range 0-3 so the answer must be 0. second number =3, it stays in the same range so the answer must be another time 0.

The same thing for every number of the vector a.

Thanks for the help,

Federico

[Jan]

Do you mean: 1, it stays in the range 0-*5*, not "0-3"?

[Federico Massetti]

Yes of course

Answer 1

[alice]

Hi,

• In Matlab, inf is the keyword for the infinity so you should avoid naming your inferior limits inf. Maybe you can name your vectors inf_lim and sup_lim ?
• One way to find the inferior limit of the interval in which a value is:

inf_lim=[0,5,10,15,20,25,30];              % inferior limits
sup_lim=[5,10,15,20,25,30,Inf];            % superior limits (I add the infinity in order to have the same number of elements)
value = 12; % value to be tested
inf_lim((value>inf_lim) & (value<sup_lim)) % the answer

• In your case, the simplest way to do it is to notice your inferior limits are all the multiple of 5 up to 30:

a=[1,3,6,12,24,35];
inf_limits = min(30,5*floor(a/5));

Answer 2

[Jan]

See histcounts:

a    = [1,3,6,12,24,35]
edge = [0,5,10,15,20,25,30,Inf];
[N, edge, bin] = histcounts(a, edge);

Now bin tells you the interval a given number fells in and edge(bin) should be the wanted anser.

Or:

bin = discretize(a, edge);
edge(bin)