Access elements of matrix(vectors and Euler angles) in Animation nodes using script node I would like to know to access individual elements of a matrix or matrices from Matrix/Matrix list input in the script node. Then I can perform some operations(experimentation) on those elements and then send them to output as a Matrix/Matrix list. I would like to do similar with Euler angles and Vectors. I am very new to programming and have searched this forum and coudn't find anything to do with this with regards to animation nodes.
Here are some examples for creating and decomposing each type:
Vector and Vector list
from mathutils import Vector

# create Vector
x = 1
y = 2
z = 3
new_vector = Vector((x,y,z))

# extract individual elements
x_element = new_vector.x # new_vector[0]
y_element = new_vector.y # new_vector[1]
z_element = new_vector.z # new_vector[2]

# create AN vector list
new_vector_list = Vector3DList()

# append element to vector List
new_vector_list.append(new_vector)
 
# get element from vector List
first_element = new_vector_list[0]

# get first element's x value
first_vector_x = new_vector_list[0].x

Euler and Euler list
from math import radians
from mathutils import Euler

# create Euler
x = radians(30)
y = radians(45)
z = radians(60)
new_euler = Euler((x,y,z)) # Euler((x,y,z),&quot;XYZ&quot;)

# extract individual elements
x_element = new_euler.x # new_euler[0]
y_element = new_euler.y # new_euler[1]
z_element = new_euler.z # new_euler[2]

# create AN euler List
new_euler_list = EulerList()

# append element to euler List
new_euler_list.append(new_euler)

# get element from euler List
first_element = new_euler_list[0]

# get first element's x value
first_element_x = new_euler_list[0].x

Matrix and Matrix list
from mathutils import Matrix, Euler, Vector

# create matrix
location = Vector((0,0,0))
rotation = Euler((0,0,0))
scale = Vector((0,0,0))
new_matrix = AN.utils.math.composeMatrix(location, rotation, scale)

# extract location
extracted_loc = new_matrix.to_translation()

# extract rotation
extracted_rot = new_matrix.to_euler()

# extract scale
extracted_scale = new_matrix.to_scale()

# create AN matrix list
new_matrix_list = Matrix4x4List()

# append element to matrix list
new_matrix_list.append(new_matrix)

# get element from matrix list
first_element = new_matrix_list[0]

# get first element's location
first_element_location = new_matrix_list[0].to_translation()

# get first element's x location
first_element_location = new_matrix_list[0].to_translation().x

# get raw matrix element
matrix_first_element = new_matrix_list[0][0]

I suggest you to look at blender api documentation for more information.