[Tutor] question on array Operation

[Steven D'Aprano]

On Wed, Oct 29, 2014 at 05:08:28PM +0100, jarod_v6 at libero.it wrote:
> Dear All,
> 
> I have a long matrix where I have the samples (1to n) and then I have (1to j )elements.
> I would like to count how many times  each j element are present on each samples.

Jarod, looking at your email address, I am guessing that English is not 
your native language. I'm afraid that I cannot understand what you are 
trying to do. Please show a *simple* example.

I will make a *guess* that you have something like this:

matrix = [ # three samples of seven values each
           [2, 4, 6, 8, 6, 9, 5], 
           [3, 5, 1, 7, 9, 8, 8], 
           [1, 2, 0, 6, 6, 2, 1],
           ]

and then you want to count how many each element [0, 1, 2, 3, 4, 5, 6, 
7, 8, 9] appear in each sample:


from collections import Counter
for i, sample in enumerate(matrix, 1):
    c = Counter(sample)
    print("Sample %d" % i)
    print(c)
    

which gives me:

Sample 1
Counter({6: 2, 2: 1, 4: 1, 5: 1, 8: 1, 9: 1})
Sample 2
Counter({8: 2, 1: 1, 3: 1, 5: 1, 7: 1, 9: 1})
Sample 3
Counter({1: 2, 2: 2, 6: 2, 0: 1})


Does that help?

If not, you have to explain what you need better.


-- 
Steven