Python 的 for 语句中的语法无效

Question

我正在尝试运行下面的代码，当我运行 python tfidf.py (Python 2.6.9) 我得到 SyntaxError: invalid syntax 错误下面一行，指向 for 语句。我做错了什么？

def produceVector(blob, bloblist):
    ##### SYNTAXERROR: invalid syntax in the "for" in the line below #####
    scores = {word: tfidf(word, blob, bloblist) for word in blob.words}
    return scores

def tf(word, blob):
    return blob.words.count(word) / len(blob.words)

def n_containing(word, bloblist):
    return sum(1 for blob in bloblist if word in blob)

def idf(word, bloblist):
    return math.log(len(bloblist) / (1 + n_containing(word, bloblist)))

def tfidf(word, blob, bloblist):
    return tf(word, blob) * idf(word, bloblist)

Answer 1

那不是 for 语句，那是听写理解。仅在 2.7 中引入。而是生成一个可迭代的 2 元组并将其传递给 dict() 构造函数。

Answer 2

a = [3, 2, 1, 0]
d = {i: a[i] for i in a}        # python > 2.6
e = dict((i, a[i]) for i in a)  # python <= 2.6 
print e == d

Python 的 for 语句中的语法无效

Invalid syntax in Python's for statement

python

for-loop

python-2.6