Discussion on: Vectors in Python

import numpy as np

# Vector in numpy
height_weight_age = np.asarray([70, 170, 40])
grades = np.asarray([85, 80, 75, 62])

# Vector addition / subtraction
print( np.asarray([1, 2, 3]) + np.asarray([4, 5, 6]) ) # => array([5, 7, 9])
print( np.asarray([5, 7, 9]) - np.asarray([4, 5, 6]) ) # => array([5, 7, 9])

# Componentwise sum
# Without `axis=0`, it would sum all matrix components
print( np.asarray([[1,2], [3,4], [5,6], [7,8]]).sum(axis=0) ) # => array([16, 20])

# Multiplying vector with a number
print( 2 * np.asarray([2, 4, 6]) ) # => array([4, 8, 12])

# Componentwise mean
print( np.asarray([[1,2], [3,4], [5,6]]).mean(axis=0) ) # => array([3., 4.])

# Dot product
print( np.asarray([1, 2, 3]).dot(np.asarray([4, 5, 6])) ) # => 32

# Sum of squares
# Equivalent to dot with self
print( np.asarray([1, 2, 3]).dot(np.asarray([1, 2, 3])) ) # => 14

# Magnitude
print( np.linalg.norm(np.asarray([3, 4])) ) # => 5.0

# Squared difference
def squared_difference(v, w):
  return (v - w).dot(v - w)

# Euclidean distance
def distance(v, w):
  return np.linalg.norm(v - w)