how to concatenate two numpy.ndarrays?

Question

How can I extend two ndarrays ?

for instance,

df = np.fromfile(f"/data/8d6ea70b_bitmex_XBTUSD_0001.dat", dtype)

df.extend( np.fromfile(f"/data/8d6ea70b_bitmex_XBTUSD_0002.dat", dtype) )

I neither see two numpy arrays in your post, nor the expected output or your attempt. — timgeb
– timgeb, Commented Nov 18, 2018 at 20:54
Numpy arrays don't have an extend method. They aren't lists. There is a poorly named np.append, but I prefer that people use np.concatenate. But take time to read its docs. — hpaulj
– hpaulj, Commented Nov 18, 2018 at 21:52

Matthieu Brucher · Accepted Answer · 2018-11-18 21:45:45Z

4

To concatenate two numpy arrays, use concatenate:

v1 = np.fromfile(f"/data/8d6ea70b_bitmex_XBTUSD_0001.dat", dtype)
v2 = np.fromfile(f"/data/8d6ea70b_bitmex_XBTUSD_0002.dat", dtype)
v = np.concatenate((v1, v2))

Then use them for a dataframe (your question being concatenating numpy arrays, not dataframes).

edited Nov 18, 2018 at 21:45

answered Nov 18, 2018 at 20:56

Matthieu Brucher

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