Fastest way to generate delimited string from 1d numpy array

Question

I have a program which needs to turn many large one-dimensional numpy arrays of floats into delimited strings. I am finding this operation quite slow relative to the mathema

Answer 1

','.join(x.astype(str))

is about 10% slower than as

x_arrstr = np.char.mod('%f', x)
x_str = ",".join(x_arrstr)

but is more readable.