how to print return function in Python

Question

It is very strange in Python that, I need specify the return vector and print them out. My original code is:

import scipy.cluster.vq as spk
result = spk.kmeans2(dataset, 5)
print result.label

or like this:

import scipy.cluster.vq as spk
print spk.kmeans2(dataset, 5).label

I got an error: AttributeError: 'tuple' object has no attribute 'label'

However, when I change the code to:

import scipy.cluster.vq as spk
code, label = spk.kmeans2(dataset, 5)
print label

The code works fine. So what is the problem?

It is not weird, you are just unpacking the returned value. Also keep in mind that a function in Python can return multiple things which are actually wrapped up with a tuple. — Ozgur Vatansever
– Ozgur Vatansever, Commented Dec 1, 2015 at 2:59

fzaziz · Accepted Answer · 2015-12-01 02:48:16Z

2

The result is a tuple. A tuple can be accessed with index. So the right way to access the data will be

import scipy.cluster.vq as spa
print spk.kmeans2(dataset, 5)[0]  # for code
print spk.kmeans2(dataset, 5)[1]  # for label

answered Dec 1, 2015 at 2:48

fzaziz

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2 Comments

That's not the right way. You processed the data twice! Tuple unpacking is a better option.

Thats right... Just an example to explain the concept of the positions of the data.