取消绑定LocalError。为什么会发生这种情况？

Question

c.execute("SELECT * FROM Student, Behaviour")
data = c.fetchall() #'data' is a tuple and cannot be altered
l = []
for i in data: #for individual records in the whole database do:
    record = str(i)
    record = record.replace("u'","")
    record = record.replace("'", "")
    record = record.replace('"', '')
    record = record.replace("(","")
    record = record.replace(")", "")
    Formattedrecord = record.replace(","," -")
l.append(Formattedrecord)

这将返回错误：UnboundLocalError:赋值前引用的局部变量'Formattedrecord' 但我不明白为什么，有人能帮忙吗？你知道吗

Answer 1

小心压痕：

c.execute("SELECT * FROM Student, Behaviour")
data = c.fetchall() #'data' is a tuple and cannot be altered
l = []
for i in data: #for individual records in the whole database do:
    record = str(i)
    record = record.replace("u'","")
    record = record.replace("'", "")
    record = record.replace('"', '')
    record = record.replace("(","")
    record = record.replace(")", "")
    Formattedrecord = record.replace(","," -")
    l.append(Formattedrecord) # this should be part of the for loop