[Numpy-discussion] Extracting data from genfromtxt?

Rohaq rohaq@dearinternet....
Fri Mar 18 15:27:17 CDT 2011


I've got a CSV file with the following layout:

Location,Result1,Result2
1,0,0
2,0,0
3,1,0
4,1,0
5,1,1
6,0,1
7,0,1
8,0,0

...etc., and I've loaded it using the following:

import numpy as np
data = np.genfromtxt('file.csv',delimiter=',',dtype=None,names=True)

Resulting in the following:

array([(1, 0, 0), (2, 0, 0), (3, 0, 0), ..., (16382, 0, 0), (16383, 0, 0),
       (16384, 0, 0)],
      dtype=[('Location', '<i8'), ('Result1', '<i8'), ('Result2', '<i8')])

I want to plot the data in matplotlib.pyplot, but I'm having trouble
reshaping the data into something it'll recognise. I can pull the
Location easily enough with data['Location'], but I need to get the
results from every other column present.

There could be a lot more than 2 other columns, Result3,Result4, etc.,
so I need to code it to be scalable; if this were acting like a normal
dict, I could write a loop that iterates over the keys, and loads the
results data into a new object, but I can't seem to find a function
that will return the keys so that I can do this.

Can anybody offer any tips for this? I'm fairly new to Python/Numpy,
so any help is appreciated.

Cheers,

Rohaq


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