问题
I am wondering if there is any build in function or an easy way to plot a histogram of elements of a 2d array.
For example, if A=rand(100,1), then A is an 1D array, and hist(A) can do the histogram.
However, what if A=rand(100,100), and I would like to make a histogram on elements of A, just like treating each element in A as an element on a 1D array. Is there a easy way to do so?
回答1:
You just have to reshape A into a vector, then you can use hist as usual:
hist(A(:))
回答2:
This command will do what you want:
hist(reshape(A, prod(size(A)), 1))
What it does is create a vector out of the matrix A by reshaping it into a matrix with one column and a number of rows equal to the number of elements of A:
prod(size(A)) = number_of_columns(A) * number_of_rows(A)
Or the short way:
hist(A(:))
This takes every element of A in sequence and thus also generates a vector.
来源：https://stackoverflow.com/questions/5568516/histogram-on-elements-of-a-2d-matrix-in-matlab