Numpy generates row vectors and column vectors (1024 water medal text)

Preface

Just pay attention , The following sentence

np.array([1,2,3])
print(np.array([1,2,3]).shape)

Not a row vector , Nor is it a column vector , You output its shape：(3,). It's something like this , You can understand that achievement is a dimension of three array.

One 、 Row vector and column vector generation

1. Row vector

# 1. The method of generating row vectors 
row_vector1 = np.array([1, 2, 3]).reshape(1, -1)  # The most commonly used 
row_vector2 = np.array([[1, 2, 3]]) # Also often used 
row_vector3 = np.expand_dims(np.array([1, 2, 3]), axis=0)# Rarely used 

2. Column vector

# 1. How to generate column vectors 
col_vector1 = np.array([1, 2, 3]).reshape(-1, 1)# The most commonly used 
col_vector2 = np.array([[1], [2], [3]])# The most commonly used 
col_vector3 = row_vector1.T  #  Vector transpose   Commonly used 
col_vector4 = np.expand_dims(np.array([1, 2, 3]), axis=1)# Rarely used 

summary

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