working with numpy arrays code example

Example 1: how to import numpy array in python

>>> import numpy as np
>>> a = np.array([0, 1, 2, 3])
>>> a
array([0, 1, 2, 3])

Example 2: get column or row of matrix array numpy python

test = numpy.array([[1, 2], [3, 4], [5, 6]])
column = test[:,0]
# column == array([1, 3, 5])
row = test[1,:]
# row == array([3, 4])

Example 3: data[:,:2]

X = dataset[:,0:3] is interpreted as "All rows for columns 0 through 3" and y = dataset[:,4] is interpreted as "all rows for column 4".