Concatenating two one-dimensional NumPy arrays

Question

I have two simple one-dimensional arrays in NumPy. I should be able to concatenate them using numpy.concatenate. But I get this error for the code below:

TypeError: only length-1 arrays can be converted to Python scalars

Code

import numpy a = numpy.array([1, 2, 3]) b = numpy.array([5, 6]) numpy.concatenate(a, b) 

Why?

Answer 1

The line should be:

numpy.concatenate([a,b]) 

The arrays you want to concatenate need to be passed in as a sequence, not as separate arguments.

From the NumPy documentation:

numpy.concatenate((a1, a2, ...), axis=0)

Join a sequence of arrays together.

It was trying to interpret your b as the axis parameter, which is why it complained it couldn't convert it into a scalar.