"""
1.在自然语言处理中常常使用预训练的word2vec,这个预训练的词向量可以使用google的GoogleNews-vectors-negative300.bin
2.GoogleNews-vectors-negative300.bin是训练好的300维的新闻语料词向量
3.本函数的作用就是把一个词转换成词向量,以供我们后期使用。没有在该word2vec中的词采用其他的方式构建,如采用均匀分布或者高斯分布等随机初始化
"""
import numpy as np # loads 300x1 word vectors from file.
def load_bin_vec(fname, vocab):
word_vecs = {}
with open(fname, "rb") as f:
header = f.readline()
vocab_size, layer1_size = map(int, header.split()) # 3000000 300
binary_len = np.dtype('float32').itemsize * layer1_size #
for line in range(vocab_size):
word = []
while True:
ch = f.read(1)
if ch == ' ':
word = ''.join(word)
break
if ch != '\n':
word.append(ch)
if word in vocab:
word_vecs[word] = np.fromstring(f.read(binary_len), dtype='float32')
else:
f.read(binary_len)
return word_vecs # add random vectors of unknown words which are not in pre-trained vector file.
# if pre-trained vectors are not used, then initialize all words in vocab with random value.
def add_unknown_words(word_vecs, vocab, min_df=1, k=300):
for word in vocab:
if word not in word_vecs and vocab[word] >= min_df:
word_vecs[word] = np.random.uniform(-0.25, 0.25, k) vectors_file = './GoogleNews-vectors-negative300.bin'
vocab = ['I', 'can', 'do'] vectors = load_bin_vec(vectors_file, vocab) # pre-trained vectors
add_unknown_words(vectors, vocab)
print(vectors['I'])
print('*'*40)
print(vectors['can'])
print('*'*40)
print(vectors['do'])