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I noticed that after each time I execute the following lines of code, my results are different. Any idea why? I think that the main issue here is this line of code But I dont understand why?

test_data['prediction']=sentiment_model.predict_proba(test_matrix)[:,0]

What is the best way to add new column with .predict_prob()?

test_data['prediction'] = sentiment_model.predict_proba(test_matrix)[:,0]
test_data['prediction_label'] = sentiment_model.predict(test_matrix) 
test_data['prediction'] = test_data['prediction'].apply(lambda x: round(x,2)) 
test_data.sort_values(by='prediction', ascending=False, inplace=True) 
test_data[test_data['name'] == 'Britax Decathlon Convertible Car Seat, Tiffany']
test_data.head() 
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  • $\begingroup$ there may be randomness at some point along the process e.g. random initialization of weights and/or biases, dataset shuffling, ... $\endgroup$ – tagoma Jul 14 '17 at 19:05
  • $\begingroup$ You need to present more of the algorithm. E.g. the setup of the model, not just getting the model results. $\endgroup$ – Pieter21 Jul 16 '17 at 11:54
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There is some randomness in the results from selecting/shuffling data that is used in the model.

If you don't want that, you could set a fixed random_state (seed) in your model.

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  • $\begingroup$ Can you please go into details, the answer is a liitle bit unclear, How can i avoid it? Why it's happening ? $\endgroup$ – David Lerech Jul 16 '17 at 6:32
  • $\begingroup$ Sorry but it's not correct I use Jupyter and I execute this lines of code, So it's not an issue of spliiting the datqa, moreever i split the data with fix values for each item $\endgroup$ – David Lerech Jul 19 '17 at 6:51
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My guess - the order of labels entered as training set is different.
From the docs -

The returned estimates for all classes are ordered by the label of classes.

So make sure you know which class prediction probability your slicing when using the [:, 0] in the first row.

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