如何计算数组中一系列自然数之间的重复数

Question

I have a sorted (Ascending trend) array as

[1 1 1 1 1 1.2 1.6 2 2 2 2.4 2.4 2.4 2.6 3 3.5 3.6 3.8 3.9 4 4.3 4.3 4.6 5 5.02 6 7]

I want to check and print the number of the repeated numbers between each "natural numbers".

for example:

between 1 and 2: 0 (no repeated)

between 2 and 3: 3 repeated with 2.4

between 3 and 4: 0

between 4 and 5: 2 repeated with 4.3

between 5 and 6: 0

between 6 and 7: 0

Is there any function in MATLAB to do this task?

Answer 1

you can use tabulate , and the array need not be even sorted for that. Then just select the proper elements using logical conditions. For example:

A=[1 1 1 1 1 1.2 1.6 2 2 2 2.4 2.4 2.4 2.6 3 3.5 3.6 3.8 3.9 4 4.3 4.3 4.6 5 5.02 6 7]
M=tabulate(A)                  % get frequency table
id1=mod(M(:,1),1)>0;           % get indices for non integer values
id2=M(:,2)>1;                  % get indices for more than one occurrence
idx=id1 & id2;                 % get indices that combines the two above
ans=[M(idx,1) , M(idx,2)]      % show value , # of repeats

ans =
    2.4000    3.0000
    4.3000    2.0000

Answer 2

the alternative is to use histc . So if your vector is stored in a then

h = histc(a,a); % count how many times the number is there, the a should be sorted
natNumbers = (mod(a,1)==0) .* h;
nonnatNum = (mod(a,1)>0).*h;
indNN = find(natNumbers>0);
indNNN = find(nonNatNumbers>1);
resultIndex = sort([indNN indNNN]);
result = [a(resultIndex);h(resultIndex)]

Then you can work with the result matrix by checking if there are any numbers between natural numbers