python lambda函數語法錯誤

Question

def get_cluster_rows():
for path, rows in itertools.groupby(get_word_rows(), key=lambda x: x[0]):
    wordcounts = [(w,c) for _,w,c in rows]
    wordcounts.sort(key=lambda (w,c): -c)

    yield path, len(wordcounts), wordcounts[:50], wordcounts

SyntaxError：語法無效：

wordcounts.sort(key=lambda (w,c): -c)
                           ^

如何用（w，c）編寫lambda函數？

Answer 1

您應該刪除括號：

wordcounts.sort(key=lambda w, c: -c)

Answer 2

只需列出您的逗號分隔參數，不帶任何方括號，例如：

f = lambda x,y: x+y
f(2,3)
5