I apologise in advance as I cannot reproduce the dataset I'm working with. So I am just going to describe steps and hope someone is familiar with the whole process.
I'm trying to use LDA Gensim to extract topics from a list of text documents.
from gensim.models import LdaModel
from gensim.corpora import Dictionary
I build dictionary and corpus:
dictionary = Dictionary(final_docs)
corpus = [dictionary.doc2bow(doc) for doc in final_docs]
where final_docs is a list of lists with cleaned tokens for each text like this:
final_docs = [['cat','dog','animal'],['school','university','education'],...['music','dj','pop']]
then I initiate the model like this:
# Set training parameters:
num_topics = 60
chunksize = 100
passes = 20
iterations = 400
eval_every = None
# Make an index to word dictionary
temp = dictionary[0] # This is only to "load" the dictionary.
id2word = dictionary.id2token
model = LdaModel(corpus=corpus, id2word=id2word, chunksize=chunksize, \
alpha='auto', eta='auto', \
iterations=iterations, num_topics=num_topics, \
passes=passes, eval_every=eval_every)
I can print topics and terms (10 most important). And they make sense. So it seems working fine.
for idx in range(n_topics):
print("Topic #%s:" % idx, model.print_topic(idx, 10))
BUT I struggle to plot all the documents as clusters using Bokeh. (And I really need Bokeh because I compare the same plot from different models). I know I have to reduce dimensionality to 2. And I try to do it using CountVectorizer and then T-sne:
from sklearn.feature_extraction.text import CountVectorizer
docs_vect = [' '.join(txt) for txt in final_docs]
cvectorizer = CountVectorizer(min_df=6, max_df=0.50, max_features=10000, stop_words=stop)
cvz = cvectorizer.fit_transform(docs_vect)
X_lda = model.fit_transform(cvz)
But I get this error: AttributeError: 'LdaModel' object has no attribute 'fit_transform'
I'm definitely doing something wrong with CountVectorizer. Could anyone help me out?
Related
I want to retrain pre-trained word embeddings in Python using Gensim. The pre-trained embeddings I want to use is Google's Word2Vec in the file GoogleNews-vectors-negative300.bin.
Following Gensim's word2vec tutorial, "it’s not possible to resume training with models generated by the C tool, load_word2vec_format(). You can still use them for querying/similarity, but information vital for training (the vocab tree) is missing there."
Therefore I can't use the KeyedVectors and for training a model the tutorial suggests to use:
model = gensim.models.Word2Vec.load('/tmp/mymodel')
model.train(more_sentences)
(https://rare-technologies.com/word2vec-tutorial/)
However, when I try this:
from gensim.models import Word2Vec
model = Word2Vec.load('data/GoogleNews-vectors-negative300.bin')
I get an error message:
1330 # Because of loading from S3 load can't be used (missing readline in smart_open)
1331 if sys.version_info > (3, 0):
-> 1332 return _pickle.load(f, encoding='latin1')
1333 else:
1334 return _pickle.loads(f.read())
UnpicklingError: invalid load key, '3'.
I didn't find a way to convert the binary google new file into a text file properly, and even if so I'm not sure whether that would solve my problem.
Does anyone have a solution to this problem or knows about a different way to retrain pre-trained word embeddings?
The Word2Vec.load() method can only load full models in gensim's native format (based on Python object-pickling) – not any other binary/text formats.
And, as per the documentation's note that "it’s not possible to resume training with models generated by the C tool", there's simply not enough information in the GoogleNews raw-vectors files to reconstruct the full working model that was used to train them. (That would require both some internal model-weights, not saved in that file, and word-frequency-information for controlling sampling, also not saved in that file.)
The best you could do is create a new Word2Vec model, then patch some/all of the GoogleNews vectors into it before doing your own training. This is an error-prone process with no real best-practices and many caveats about the interpretation of final results. (For example, if you bring in all the vectors, but then only re-train a subset using only your own corpus & word-frequencies, the more training you do – making the word-vectors better fit your corpus – the less such re-trained words will have any useful comparability to retained untrained words.)
Essentially, if you can look at the gensim Word2Vec source & work-out how to patch-together such a frankenstein-model, it may be appropriate. But there's no built-in support or handy off-the-shelf recipes that make it easy, because it's an inherently murky process.
I have already answered it here .
Save the google news model as text file in wor2vec format using gensim.
Refer this answer to save it as text file
Then try this code .
import os
import pickle
import numpy as np
import gensim
from gensim.models import Word2Vec, KeyedVectors
from gensim.models.callbacks import CallbackAny2Vec
import operator
os.mkdir("model_dir")
# class EpochSaver(CallbackAny2Vec):
# '''Callback to save model after each epoch.'''
# def __init__(self, path_prefix):
# self.path_prefix = path_prefix
# self.epoch = 0
# def on_epoch_end(self, model):
# list_of_existing_files = os.listdir(".")
# output_path = 'model_dir/{}_epoch{}.model'.format(self.path_prefix, self.epoch)
# try:
# model.save(output_path)
# except:
# model.wv.save_word2vec_format('model_dir/model_{}.bin'.format(self.epoch), binary=True)
# print("number of epochs completed = {}".format(self.epoch))
# self.epoch += 1
# list_of_total_files = os.listdir(".")
# saver = EpochSaver("my_finetuned")
# function to load vectors from existing model.
# I am loading glove vectors from a text file, benefit of doing this is that I get complete vocab of glove as well.
# If you are using a previous word2vec model I would recommed save that in txt format.
# In case you decide not to do it, you can tweak the function to get vectors for words in your vocab only.
def load_vectors(token2id, path, limit=None):
embed_shape = (len(token2id), 300)
freqs = np.zeros((len(token2id)), dtype='f')
vectors = np.zeros(embed_shape, dtype='f')
i = 0
with open(path, encoding="utf8", errors='ignore') as f:
for o in f:
token, *vector = o.split(' ')
token = str.lower(token)
if len(o) <= 100:
continue
if limit is not None and i > limit:
break
vectors[token2id[token]] = np.array(vector, 'f')
i += 1
return vectors
# path of text file of your word vectors.
embedding_name = "word2vec.txt"
data = "<training data(new line separated tect file)>"
# Dictionary to store a unique id for each token in vocab( in my case vocab contains both my vocab and glove vocab)
token2id = {}
# This dictionary will contain all the words and their frequencies.
vocab_freq_dict = {}
# Populating vocab_freq_dict and token2id from my data.
id_ = 0
training_examples = []
file = open("{}".format(data),'r', encoding="utf-8")
for line in file.readlines():
words = line.strip().split(" ")
training_examples.append(words)
for word in words:
if word not in vocab_freq_dict:
vocab_freq_dict.update({word:0})
vocab_freq_dict[word] += 1
if word not in token2id:
token2id.update({word:id_})
id_ += 1
# Populating vocab_freq_dict and token2id from glove vocab.
max_id = max(token2id.items(), key=operator.itemgetter(1))[0]
max_token_id = token2id[max_id]
with open(embedding_name, encoding="utf8", errors='ignore') as f:
for o in f:
token, *vector = o.split(' ')
token = str.lower(token)
if len(o) <= 100:
continue
if token not in token2id:
max_token_id += 1
token2id.update({token:max_token_id})
vocab_freq_dict.update({token:1})
with open("vocab_freq_dict","wb") as vocab_file:
pickle.dump(vocab_freq_dict, vocab_file)
with open("token2id", "wb") as token2id_file:
pickle.dump(token2id, token2id_file)
# converting vectors to keyedvectors format for gensim
vectors = load_vectors(token2id, embedding_name)
vec = KeyedVectors(300)
vec.add(list(token2id.keys()), vectors, replace=True)
# setting vectors(numpy_array) to None to release memory
vectors = None
params = dict(min_count=1,workers=14,iter=6,size=300)
model = Word2Vec(**params)
# using build from vocab to build the vocab
model.build_vocab_from_freq(vocab_freq_dict)
# using token2id to create idxmap
idxmap = np.array([token2id[w] for w in model.wv.index2entity])
# Setting hidden weights(syn0 = between input layer and hidden layer) = your vectors arranged accoring to ids
model.wv.vectors[:] = vec.vectors[idxmap]
# Setting hidden weights(syn0 = between hidden layer and output layer) = your vectors arranged accoring to ids
model.trainables.syn1neg[:] = vec.vectors[idxmap]
model.train(training_examples, total_examples=len(training_examples), epochs=model.epochs)
output_path = 'model_dir/final_model.model'
model.save(output_path)
I want to perform text classification using word2vec.
I got vectors of words.
ls = []
sentences = lines.split(".")
for i in sentences:
ls.append(i.split())
model = Word2Vec(ls, min_count=1, size = 4)
words = list(model.wv.vocab)
print(words)
vectors = []
for word in words:
vectors.append(model[word].tolist())
data = np.array(vectors)
data
output:
array([[ 0.00933912, 0.07960335, -0.04559333, 0.10600036],
[ 0.10576613, 0.07267512, -0.10718666, -0.00804013],
[ 0.09459028, -0.09901826, -0.07074171, -0.12022413],
[-0.09893986, 0.01500741, -0.04796079, -0.04447284],
[ 0.04403428, -0.07966098, -0.06460238, -0.07369237],
[ 0.09352681, -0.03864434, -0.01743148, 0.11251986],.....])
How can i perform classification (product & non product)?
You already have the array of word vectors using model.wv.syn0. If you print it, you can see an array with each corresponding vector of a word.
You can see an example here using Python3:
import pandas as pd
import os
import gensim
import nltk as nl
from sklearn.linear_model import LogisticRegression
#Reading a csv file with text data
dbFilepandas = pd.read_csv('machine learning\\Python\\dbSubset.csv').apply(lambda x: x.astype(str).str.lower())
train = []
#getting only the first 4 columns of the file
for sentences in dbFilepandas[dbFilepandas.columns[0:4]].values:
train.extend(sentences)
# Create an array of tokens using nltk
tokens = [nl.word_tokenize(sentences) for sentences in train]
Now it's time to use the vector model, in this example we will calculate the LogisticRegression.
# method 1 - using tokens in Word2Vec class itself so you don't need to train again with train method
model = gensim.models.Word2Vec(tokens, size=300, min_count=1, workers=4)
# method 2 - creating an object 'model' of Word2Vec and building vocabulary for training our model
model = gensim.models.Word2vec(size=300, min_count=1, workers=4)
# building vocabulary for training
model.build_vocab(tokens)
print("\n Training the word2vec model...\n")
# reducing the epochs will decrease the computation time
model.train(tokens, total_examples=len(tokens), epochs=4000)
# You can save your model if you want....
# The two datasets must be the same size
max_dataset_size = len(model.wv.syn0)
Y_dataset = []
# get the last number of each file. In this case is the department number
# this will be the 0 or 1, or another kind of classification. ( to use words you need to extract them differently, this way is to numbers)
with open("dbSubset.csv", "r") as f:
for line in f:
lastchar = line.strip()[-1]
if lastchar.isdigit():
result = int(lastchar)
Y_dataset.append(result)
else:
result = 40
clf = LogisticRegression(random_state=0, solver='lbfgs', multi_class='multinomial').fit(model.wv.syn0, Y_dataset[:max_dataset_size])
# Prediction of the first 15 samples of all features
predict = clf.predict(model.wv.syn0[:15, :])
# Calculating the score of the predictions
score = clf.score(model.wv.syn0, Y_dataset[:max_dataset_size])
print("\nPrediction word2vec : \n", predict)
print("Score word2vec : \n", score)
You can also calculate the similarity of words belonging to your created model dictionary:
print("\n\nSimilarity value : ",model.wv.similarity('women','men'))
You can find more functions to use here.
Your question is rather broad but I will try to give you a first approach to classify text documents.
First of all, I would decide how I want to represent each document as one vector. So you need a method that takes a list of vectors (of words) and returns one single vector. You want to avoid that the length of the document influences what this vector represents. You could for example choose the mean.
def document_vector(array_of_word_vectors):
return array_of_word_vectors.mean(axis=0)
where array_of_word_vectors is for example data in your code.
Now you can either play a bit around with distances (for example cosine distance would a nice first choice) and see how far certain documents are from each other or - and that's probably the approach that brings faster results - you can use the document vectors to build a training set for a classification algorithm of your choice from scikit learn, for example Logistic Regression.
The document vectors will become your matrix X and your vector y is an array of 1 and 0, depending on the binary category that you want the documents to be classified into.
I am trying to implement K-Nearest Neighbours algorithm from scratch in Python. The code I wrote worked well for the Breast-Cancer-Wisconsin.csv dataset.
However, the same code when I try to run for Iris.csv dataset, my implementation fails and gives KeyError.
The only difference in the 2 datasets is the fact that in Breast-Cancer-Wisconsin.csv there are only 2 classes ('2' for malignant and '4' for benign) and both the labels are integers wheres in Iris.csv there are 3 classes ('setosa', 'versicolor', 'virginica') and all these 3 labels are in string type.
Here is the code I wrote (for Iris.csv) :
import numpy as np
from math import sqrt
import matplotlib.pyplot as plt
from matplotlib import style
from collections import Counter
import warnings
import pandas as pd
import random
style.use('fivethirtyeight')
dataset = {'k':[[1,2],[2,3],[3,1]], 'r':[[6,5],[7,7],[8,6]]}
new_features = [5,7]
#[[plt.scatter(j[0],j[1], s=100, color=i) for j in dataset[i]] for i in dataset]
#plt.scatter(new_features[0], new_features[1], s=100)
#plt.show()
def k_nearest_neighbors(data, predict, k=3):
if len(data) >= k:
warnings.warn('K is set to a value less than total voting groups!')
distances = []
for group in data:
for features in data[group]:
euclidean_distance = np.linalg.norm(np.array(features) - np.array(predict))
distances.append([euclidean_distance, group])
votes = [i[1] for i in sorted(distances)[:k]]
vote_result = Counter(votes).most_common(1)[0][0]
return vote_result
df = pd.read_csv('iris.csv')
df.replace('?', -99999, inplace=True)
#full_data = df.astype(float).values.tolist()
#random.shuffle(full_data)
test_size = 0.2
train_set = {'setosa':[], 'versicolor':[], 'virginica':[]}
test_set = {'setosa':[], 'versicolor':[], 'virginica':[]}
train_data = full_data[:-int(test_size*len(full_data))]
test_data = full_data[-int(test_size*len(full_data)):]
for i in train_data:
train_set[i[-1]].append(i[:-1])
for i in test_data:
test_set[i[-1]].append(i[:-1])
correct = 0
total = 0
for group in test_set:
for data in test_set[group]:
vote = k_nearest_neighbors(train_set, data, k=5)
if group == vote:
correct += 1
total += 1
print('Accuracy : ', correct/total)
When I run the above code, I get a KeyError message at line number 49.
Could anyone please explain to me where I am going wrong? Also, it would be great if someone could point out how do I modify this algorithm to classify multiple classes (instead of 2 or 3) in the future?
Also, how do I handle if the classes are in string type instead of integer?
one solution I thought of was to convert all string types to integer types and try to solve but would that work?
REFERENCES
Iris.csv
Breas-Cancer-Wisconsin.csv
Let's start from your last question:
one solution I thought of was to convert all string types to integer types and try to solve but would that work?
Yes, that would work. You shouldn't have to hardcode the names of all the classes of every problem in your code. Instead, you can just write a function that reads all the different values for the class attribute, and assigns a numeric value to each different one.
Could anyone please explain to me where I am going wrong?
Most likely, the problem is that you are reading an instance whose class attribute is not 'setosa', 'versicolor', 'virginica' (something like Iris-setosa perhaps?). The idea above should fix this problem.
Also, it would be great if someone could point out how do I modify this algorithm to classify multiple classes (instead of 2 or 3) in the future?
As discuss before, you just need to avoid hard-coding the names of the classes in your code
Also, how do I handle if the classes are in string type instead of integer?
def get_class_values(data):
classes_seen = {}
for i in data:
_class = data[-1]
if _class not in classes_seen:
classes_seen[_class] = len(classes_seen)
return classes_seen
A function like this one would return a mapping between all your classes (no matter the type) and numeric codes (from 0 to N-1). Using this mapping would also solve all the problems mentioned before.
Convert String Labels In CSV Files To Integer Labels
After going through some GitHub repos I came across a very simple yet elegant piece of code that solves the above problem. Hope it helps those who have faced this problem before (beginners especially!)
% read the csv file
df = pd.read_csv('iris.csv')
% clean the data file
df.replace('?', -99999, inplace=True)
% convert the string classes into integer types.
% integers are assigned from 0 to N-1.
% species is the name of the column which has class labels.
df['species'] = df['species'].astype('category')
df['species_value'] = df['species'].cat.codes
df.drop(['species'], 1, inplace=True)
% convert the data frame to list
full_data = df.astype(float).values.tolist()
random.shuffle(full_data)
Post Debugging
Turns out that we need not use the above piece of code also, i.e I can get the answer without explicitly converting the string labels into integer labels (using the above code).
I have posted the original code after some minor changes (below) and the key error is now fixed. Also, I am now getting an accuracy of 97% to 100% (only on IRIS dataset).
test_size = 0.2
train_set = {0:[], 1:[], 2:[]}
test_set = {0:[], 1:[], 2:[]}
That is the only change you need to make to the original code I posted in order to make it work!! Simple!
However, please note that the numbers have to be given as integers and not string (otherwise it would lead to key error!).
Wrap-Up
There are some commented lines in the original code which I thought would be good to explain in case somebody ran into some issues. Here's one snippet with the comments removed (compare with original code in the question).
df = pd.read_csv('iris.csv')
df.replace('?', -99999, inplace=True)
full_data = df.astype(float).values.tolist()
random.shuffle(full_data)
Here's the output you get:
ValueError: could not convert string to float: 'virginica'
What went wrong?
Note that here we did not convert the string labels into integer labels. Therefore, when we tried to convert the data in the CSV to float values, the kernel threw an error because a string cannot be converted to float!
So one way to go about it is that you don't convert the data into floating point values and then you won't get this error. However in many cases you need to convert all the data into floating point (for eg.. normalisation, accuracy, long mathematical calculations, prevention of loss of precision etc etc..).
Hence after heavy debugging and going through a lot of articles I finally came up with a simple version of the original code (below):
import numpy as np
from math import sqrt
import matplotlib.pyplot as plt
from matplotlib import style
from collections import Counter
import warnings
import pandas as pd
import random
def k_nearest_neighbors(data, predict, k=3):
if len(data) >= k:
warnings.warn('K is set to a value less than total voting groups!')
distances = []
for group in data:
for features in data[group]:
euclidean_distance = np.linalg.norm(np.array(features) - np.array(predict))
distances.append([euclidean_distance, group])
votes = [i[1] for i in sorted(distances)[:k]]
vote_result = Counter(votes).most_common(1)[0][0]
return vote_result
df = pd.read_csv('iris.csv')
df.replace('?', -99999, inplace=True)
df['species'] = df['species'].astype('category')
df['species_value'] = df['species'].cat.codes
df.drop(['species'], 1, inplace=True)
full_data = df.astype(float).values.tolist()
random.shuffle(full_data)
test_size = 0.2
train_set = {0:[], 1:[], 2:[]}
test_set = {0:[], 1:[], 2:[]}
train_data = full_data[:-int(test_size*len(full_data))]
test_data = full_data[-int(test_size*len(full_data)):]
for i in train_data:
train_set[i[-1]].append(i[:-1])
for i in test_data:
test_set[i[-1]].append(i[:-1])
correct = 0
total = 0
for group in test_set:
for data in test_set[group]:
vote = k_nearest_neighbors(train_set, data, k=5)
if group == vote:
correct += 1
total += 1
print('Accuracy : ', (correct/total)*100,'%')
Hope this helps!
I have trained a doc2vec and corresponding word2vec on my own corpus using gensim. I want to visualise the word2vec using t-sne with the words. As in, each dot in the figure has the "word" also with it.
I looked at a similar question here : t-sne on word2vec
Following it, I have this code :
import gensim
import gensim.models as g
from sklearn.manifold import TSNE
import re
import matplotlib.pyplot as plt
modelPath="/Users/tarun/Desktop/PE/doc2vec/model3_100_newCorpus60_1min_6window_100trainEpoch.bin"
model = g.Doc2Vec.load(modelPath)
X = model[model.wv.vocab]
print len(X)
print X[0]
tsne = TSNE(n_components=2)
X_tsne = tsne.fit_transform(X[:1000,:])
plt.scatter(X_tsne[:, 0], X_tsne[:, 1])
plt.show()
This gives a figure with dots but no words. That is I don't know which dot is representative of which word. How can I display the word with the dot?
Two parts to the answer: how to get the word labels, and how to plot the labels on a scatterplot.
Word labels in gensim's word2vec
model.wv.vocab is a dict of {word: object of numeric vector}. To load the data into X for t-SNE, I made one change.
vocab = list(model.wv.key_to_index)
X = model.wv[vocab]
This accomplishes two things: (1) it gets you a standalone vocab list for the final dataframe to plot, and (2) when you index model, you can be sure that you know the order of the words.
Proceed as before with
tsne = TSNE(n_components=2)
X_tsne = tsne.fit_transform(X)
Now let's put X_tsne together with the vocab list. This is easy with pandas, so import pandas as pd if you don't have that yet.
df = pd.DataFrame(X_tsne, index=vocab, columns=['x', 'y'])
The vocab words are the indices of the dataframe now.
I don't have your dataset, but in the other SO you mentioned, an example df that uses sklearn's newsgroups would look something like
x y
politics -1.524653e+20 -1.113538e+20
worry 2.065890e+19 1.403432e+20
mu -1.333273e+21 -5.648459e+20
format -4.780181e+19 2.397271e+19
recommended 8.694375e+20 1.358602e+21
arguing -4.903531e+19 4.734511e+20
or -3.658189e+19 -1.088200e+20
above 1.126082e+19 -4.933230e+19
Scatterplot
I like the object-oriented approach to matplotlib, so this starts out a little different.
fig = plt.figure()
ax = fig.add_subplot(1, 1, 1)
ax.scatter(df['x'], df['y'])
Lastly, the annotate method will label coordinates. The first two arguments are the text label and the 2-tuple. Using iterrows(), this can be very succinct:
for word, pos in df.iterrows():
ax.annotate(word, pos)
[Thanks to Ricardo in the comments for this suggestion.]
Then do plt.show() or fig.savefig(). Depending on your data, you'll probably have to mess with ax.set_xlim and ax.set_ylim to see into a dense cloud. This is the newsgroup example without any tweaking:
You can modify dot size, color, etc., too. Happy fine-tuning!
With the following, you can convert your model to a TSV and then use this page for visualization.
with open(self.word_tensors_TSV, 'bw') as file_vector, open(self.word_meta_TSV, 'bw') as file_metadata:
for word in model.wv.vocab:
file_metadata.write((word + '\n').encode('utf-8', errors='replace'))
vector_row = '\t'.join(str(x) for x in model[word])
file_vector.write((vector_row + '\n').encode('utf-8', errors='replace'))
:)
I have created a Gaussian Naive Bayes classifier on a email (spam/not spam) dataset and was able to run it successfully. I vectorized the data, divided in it train and test sets and then calculated the accuracy, all the features that are present in the sklearn-Gaussian Naive Bayes classifier.
Now I want to be able to use this classifier to predict "labels" for new emails - whether they are by spam or not.
For example say I have an email. I want to feed it to my classifier and get the prediction as to whether it is a spam or not. How can I achieve this? Please Help.
Code for classifier file.
#!/usr/bin/python
import sys
from time import time
import logging
# Display progress logs on stdout
logging.basicConfig(level = logging.DEBUG, format = '%(asctime)s %(message)s')
sys.path.append("../DatasetProcessing/")
from vectorize_split_dataset import preprocess
### features_train and features_test are the features
for the training and testing datasets, respectively### labels_train and labels_test are the corresponding item labels
features_train, features_test, labels_train, labels_test = preprocess()
#########################################################
from sklearn.naive_bayes import GaussianNB
clf = GaussianNB()
t0 = time()
clf.fit(features_train, labels_train)
pred = clf.predict(features_test)
print("training time:", round(time() - t0, 3), "s")
print(clf.score(features_test, labels_test))
## Printing Metrics
for Training and Testing
print("No. of Testing Features:" + str(len(features_test)))
print("No. of Testing Features Label:" + str(len(labels_test)))
print("No. of Training Features:" + str(len(features_train)))
print("No. of Training Features Label:" + str(len(labels_train)))
print("No. of Predicted Features:" + str(len(pred)))
## Calculating Classifier Performance
from sklearn.metrics import classification_report
y_true = labels_test
y_pred = pred
labels = ['0', '1']
target_names = ['class 0', 'class 1']
print(classification_report(y_true, y_pred, target_names = target_names, labels = labels))
# How to predict label of a new text
new_text = "You won a lottery at UK lottery commission. Reply to claim it"
Code for Vectorization
#!/usr/bin/python
import os
import pickle
import numpy
numpy.random.seed(42)
path = os.path.dirname(os.path.abspath(__file__))
### The words(features) and label_data(labels), already largely processed.###These files should have been created beforehand
feature_data_file = path + "./createdDataset/dataSet.pkl"
label_data_file = path + "./createdDataset/dataLabel.pkl"
feature_data = pickle.load(open(feature_data_file, "rb"))
label_data = pickle.load(open(label_data_file, "rb"))
### test_size is the percentage of events assigned to the test set(the### remainder go into training)### feature matrices changed to dense representations
for compatibility with### classifier functions in versions 0.15.2 and earlier
from sklearn import cross_validation
features_train, features_test, labels_train, labels_test = cross_validation.train_test_split(feature_data, label_data, test_size = 0.1, random_state = 42)
from sklearn.feature_extraction.text import TfidfVectorizer
vectorizer = TfidfVectorizer(sublinear_tf = True, max_df = 0.5, stop_words = 'english')
features_train = vectorizer.fit_transform(features_train)
features_test = vectorizer.transform(features_test)#.toarray()
## feature selection to reduce dimensionality
from sklearn.feature_selection import SelectPercentile, f_classif
selector = SelectPercentile(f_classif, percentile = 5)
selector.fit(features_train, labels_train)
features_train_transformed_reduced = selector.transform(features_train).toarray()
features_test_transformed_reduced = selector.transform(features_test).toarray()
features_train = features_train_transformed_reduced
features_test = features_test_transformed_reduced
def preprocess():
return features_train, features_test, labels_train, labels_test
Code for dataset generation
#!/usr/bin/python
import os
import pickle
import re
import sys
# sys.path.append("../tools/")
""
"
Starter code to process the texts of accuate and inaccurate category to extract
the features and get the documents ready for classification.
The list of all the texts from accurate category are in the accurate_files list
likewise for texts of inaccurate category are in (inaccurate_files)
The data is stored in lists and packed away in pickle files at the end.
"
""
accurate_files = open("./rawDatasetLocation/accurateFiles.txt", "r")
inaccurate_files = open("./rawDatasetLocation/inaccurateFiles.txt", "r")
label_data = []
feature_data = []
### temp_counter is a way to speed up the development--there are### thousands of lines of accurate and inaccurate text, so running over all of them### can take a long time### temp_counter helps you only look at the first 200 lines in the list so you### can iterate your modifications quicker
temp_counter = 0
for name, from_text in [("accurate", accurate_files), ("inaccurate", inaccurate_files)]:
for path in from_text: ###only look at first 200 texts when developing### once everything is working, remove this line to run over full dataset
temp_counter = 1
if temp_counter < 200:
path = os.path.join('..', path[: -1])
print(path)
text = open(path, "r")
line = text.readline()
while line: ###use a
function parseOutText to extract the text from the opened text# stem_text = parseOutText(text)
stem_text = text.readline().strip()
print(stem_text)### use str.replace() to remove any instances of the words# stem_text = stem_text.replace("germani", "")### append the text to feature_data
feature_data.append(stem_text)### append a 0 to label_data
if text is from Sara, and 1
if text is from Chris
if (name == "accurate"):
label_data.append("0")
elif(name == "inaccurate"):
label_data.append("1")
line = text.readline()
text.close()
print("texts processed")
accurate_files.close()
inaccurate_files.close()
pickle.dump(feature_data, open("./createdDataset/dataSet.pkl", "wb"))
pickle.dump(label_data, open("./createdDataset/dataLabel.pkl", "wb"))
Also I want to know whether i can incrementally train the classifier meaning thereby that retrain a created model with newer data for refining the model over time?
I would be really glad if someone can help me out with this. I am really stuck at this point.
You are already using your model to predict labels of emails in your test set. This is what pred = clf.predict(features_test) does. If you want to see these labels, do print pred.
But perhaps you what to know how you can predict labels for emails that you discover in the future and that are not currently in your test set? If so, you can think of your new email(s) as a new test set. As with your previous test set, you will need to run several key processing steps on the data:
1) The first thing you need to do is to generate features for your new email data. The feature generation step is not included in your code above, but will need to occur.
2) You are using a Tfidf vectorizer, which converts a collection of documents to a matrix of Tfidf features based upon term frequency and inverse document frequency. You need to put your new email test feature data through the vectorizer that you fit on your training data.
3) Then your new email test feature data will need to go through dimensionality reduction using the same selector that you fit on your training data.
4) Finally, run predict on your new test data. Use print pred if you want to view the new label(s).
To respond to your final question about iteratively re-training your model, yes you definitely can do this. It's just a matter of selecting a frequency, producing a script that expands your data set with incoming data, then re-running all steps from there, from pre-processing to Tfidf vectorization, to dimensionality reduction, to fitting, and prediction.