Concatenate a NumPy array to another NumPy array
In [1]: import numpy as npIn [2]: a = np.array([[1, 2, 3], [4, 5, 6]])In [3]: b = np.array([[9, 8, 7], [6, 5, 4]])In [4]: np.concatenate((a, b))Out[4]: array([[1, 2, 3], [4, 5, 6], [9, 8, 7], [6, 5, 4]])
or this:
In [1]: a = np.array([1, 2, 3])In [2]: b = np.array([4, 5, 6])In [3]: np.vstack((a, b))Out[3]: array([[1, 2, 3], [4, 5, 6]])
Well, the error message says it all: NumPy arrays do not have an append()
method. There's a free function numpy.append()
however:
numpy.append(M, a)
This will create a new array instead of mutating M
in place. Note that using numpy.append()
involves copying both arrays. You will get better performing code if you use fixed-sized NumPy arrays.