Q:

np.save is converting floats to weird characters

I am attempting to append results to an ongoing csv file. Each result comes out as an nd.array:
[IN]:  Print(savearray)
[OUT]: [[ 0.55219001  0.39838119]]

Initially I tried 
np.savetxt('flux_ratios.csv', savearray,delimiter=",")

But this overwrites the old data every time I save, so instead I am attempting to append the data like this:
f = open('flux_ratios.csv', 'ab')
np.save(f, 'a',savearray)
f.close()

This is (in a sense) appending, however it is saving the numerical data as weird characters, as can be seen in this screenshot:

I have no idea why or how this is happening so any help would be greatly appreciated!

A:

First off, np.save does not write text whereas np.savetxt does. You are trying to combine binary with text, which is why you get the odd characters when you try to read the file.
You could just change np.save(f, 'a', savearray) to np.savetxt(f, savearray, delimiter=',').
Otherwise you could also consider using pandas.to_csv in append mode. 

