How can I plot histogram using b as x value and k as bin values? plotting histogram error line 16

load sizes2.txt
results= sizes2(:,1) 
n=size(sizes2,1) % num of rows 
a=sizes2(:,:)
b=sort(a)
y=log10(n)
k= 1+3.322*y %  is suggested number of class intervals and n is the number of values in the data set

fprintf('The suggested number of class intervals is %d\n', k );

x=range(b)
w=x/k         % width of class intervals 
fprintf('The suggested number of class intervals is %d\n', w)
k=8
hist(b,k)

Thank you

[rathod ujjval rameshbhai]

i think k should be integer

[Jackie]

the first k in line 7 is a double but then I just used the variable k to define it as 8, an integer, should I rename the variable?

[Jackie]

So, I changed the name to nbin but I still get the same error: Subscript indices must either be real positive integers or logicals.

load sizes2.txt
results= sizes2(:,1) 
n=size(sizes2,1) % num of rows 
a=sizes2(:,:)
b=sort(a)
y=log10(n)
k= 1+3.322*y %  is suggested number of class intervals and n is the number of values in the data set

fprintf('The suggested number of class intervals is %d\n', k );
nbin=8
x=range(b)
w=x/nbin         % width of class intervals 
fprintf('The suggested number of class intervals is %d\n', w)
nbin=8
hist(b,nbin)

[dpb]

nbins ~= integer doesn't cause the above error; it does change the binning calculation.

Need to attach your data to test to see what might be going on here.

[Jackie]

Hi, ok thanks just uploaded the txt file

[dpb]

I can't reproduce an error; I would simplify quite a lot, but I get no error...I did just paste the data from the text file into the command window as variable sizes. Whatever is causing the above error is somewhere else than in the above.

>> n=length(sizes);
>> k=1+3.322*log10(n)  % without rounding
k =
  8.3130
>> k1=fix(k); % truncate; use round() if to nearest integer
>> n=hist(sizes,k)  % with the non-integer value
n =
  58    51    27    11     4     4     2     2
>> m=hist(sizes,k1) % and the integer version...
m =
  58    56    22    14     2     3     2     2
>> sum(m)==sum(n)  % both get all the elements
ans =
   1
>> hist(sort(sizes),k1)  % and to so you don't need sort()
>> o=hist(sort(sizes),k1)
o =
  58    56    22    14     2     3     2     2
>>

I didn't delve into the code of hist to see just exactly what it's doing with the non-integer bins; clearly it also truncated to the integer number but it did modify the binning as can be seen comparing the two outputs.

But, it doesn't cause an indexing error (and it doesn't appear to be the problem in your case as you still got an error)

Oh; you haven't by chance inadvertently created a variable hist, have you? Try

clear hist

and then try again...or, to see before clear try

which hist

[Jackie]

Hi, thank you so much for the clarification actually yeah I think at some point when I was trying to put this together I accidentally at some point put hist=... and later realized that this can't be done . Once I put clear hist the historgram was plotting as desired. Thank you again

Answer 1

[Image Analyst]

Why not just call histcounts() and then bar()?