word2vec - KeyError：“单词 X 不在词汇表中”

使用Word2Vec模块的实现为gensim我在纯文本文件中的句子构建词嵌入。尽管happy在词汇表中定义了这个词，但还是出现了错误KeyError: "word 'happy' not in vocabulary"。试图将给定的答案应用于类似问题，但没有奏效。因此，发布了我自己的问题。

这是代码：

try:
    data = []
    with open(TXT_PATH, 'r', encoding='utf-8') as txt_file:
        for line in txt_file:
            for part in line.split(' '):
                data.append(part.strip())

    # When I debug, both of the words 'happy' and 'birthday' exist in the variable 'data'
    word2vec = Word2Vec(data, min_count=5, size=10000, window=5, workers=4)

    # Print result
    word_1 = 'happy'
    word_2 = 'birthday'
    print(f'Similarity between {word_1} and {word_2} thru word2vec: {word2vec.similarity(word_1, word_2)}')
except Exception as err:
    print(f'An error happened! Detail: {str(err)}')