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Python - From a list of matrices, create an array containing the i-th and j-th element of each matrix?

How to Python - From a list of matrices, create an array containing the i-th and j-th element of each matrix

I have a list of matirces each containing pixel values of a screen at a given moment. Matrix1 contains pixel values at moment1, matrix2 contains pixel values at moment2 and so on. Lets say I want to take a look at how one individual pixel evolves throughout time. I created some dummy matrices to test how that would work and put them in mylist:

m1=[[1,2],[3,4]]
m2=[[1,2],[3,4]]
m3=[[5,6],[7,8]]

mylist=[m1,m2,m3]

print(mylist)

Then I wanted to select the (0,0) element of the second matrix:


print(mylist[1][1][0])

This gives me the expected output 1. Then I wanted to generalize it and pick the (0,0) element of every matrix, which should give me the output mynewlist=[1,1,5]:

mynewlist=[]

for i in 2:
    mynewlist.append(mylist[i][1][0])
    
print("hello hello")
print(mynewlist)

However, it gives me the error message:

for i in 2:
TypeError: 'int' object is not iterable

What did I do wrong? How can I bypass this problem? Is there any other (most propably smoother and better) way to select the (i,j) element from each matrix?

Solution:

A better aproach would be to directly loop through the ellement of mylist as:

   mynewlist = [] 
   for image in mylist:
       mynewlist.append(image[1][0])

This makes your code more readible. And now it doesn't matter how many images you have in your initial list.