I created a ndarray from a txt file using numpy.genfromtxt. The txt file looks like:
2505000
10.316 1.936 0.025 0 15 0 0
10.316 1.937 0.028 0 15 0 0
10.316 1.943 0.028 0 15 0 0
10.316 1.954 0.022 0 9 58 0
10.316 1.955 0.026 0 9 58 0
I am running the reading the data with:
data = np.genfromtxt(fname,
skip_header =1,
dtype = [('X','f'),('Y','f'),('Z','f'),('V', 'i'),('T', 'i')],
usecols = (0,1,2,4,5))
I am now trying to duplicate the 4th column (the one I called V) and place it just after itself (before the last T column).
I know I can copy the column by doing data['V'], but how do I place this copy in between V and T (the 4th and 5th columns)? I had a look at numpy.insert, but I am not sure how to specify the index (the obj argument). I tried with numpy.insert(data_copy, data_copy['T'],data_copy['V']) with no luck (I received IndexError: index 61 is out of bounds for size 20).
You have to make a new dtype with the added field, and copy values by field name from the original array to the new one.
recfunctions has functions to do this (and related actions):
from numpy.lib import recfunctions