import numpy as np
a = np.array([1, 2, 3]) # Create a rank 1 array
print(type(a)) # Prints "<class 'numpy.ndarray'>"
print(a.shape) # Prints "(3,)"
print(a[0], a[1], a[2]) # Prints "1 2 3"
a[0] = 5 # Change an element of the array
print(a) # Prints "[5, 2, 3]"
b = np.array([[1,2,3],[4,5,6]]) # Create a rank 2 array
print("forma")
print(b.shape) # Prints "(2, 3)"
print(b[0, 0], b[0, 1], b[1, 0]) # Prints "1 2 4"
print("Matriz")
a1 = np.array([[1,2,3,4], [5,6,7,8], [9,10,11,12]])
print(a1)
# Two ways of accessing the data in the middle row of the array.
# Mixing integer indexing with slices yields an array of lower rank,
# while using only slices yields an array of the same rank as the
# original array:
row_r1 = a1[0, :] # Rank 1 view of the second row of a
row_r2 = a1[1:2, :] # Rank 2 view of the second row of a
print("renglon 0")
print(row_r1, row_r1.shape) # Prints "[5 6 7 8] (4,)"
print("renglon 1")
print(row_r2, row_r2.shape) # Prints "[[5 6 7 8]] (1, 4)"
# We can make the same distinction when accessing columns of an array:
col_r1 = a1[:, 0]
col_r2 = a1[:, 1:2]
print("columna 0")
print(col_r1, col_r1.shape) # Prints "[ 2 6 10] (3,)"
print("columna 1")
print(col_r2, col_r2.shape) # Prints "[[ 2]
# [ 6]
# [10]] (3, 1)"
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