[python2]local variable referenced before assignment问题

Question

class Test(obj):

def __init__(self):
    pass
    
def _is_flag(self):
    try:
        v_sql="""
        Select count(*)
          From tablename
        """
        push_ctrl_conn=oracle('ETL_TEST')
        self.reach_flag=push_ctrl_conn.runsql(v_sql,1)[0][0]
    except Exception,e:
        self._set_scan_state('22', str(e))
    finally:
        push_ctrl_conn.close()
        
def run(self):
    self._is_flag()

if name == '__main__':

test_case=Test()
test_case.run()

类似这种格式,然后就报了
UnboundLocalError: local variable 'push_ctrl_conn' referenced before assignment

Answer 1

Blok sintaks try mungkin tidak dapat dilaksanakan, iaitu, push_ctrl_conn mungkin tidak diberikan nilai. Kesilapan yang sangat biasa, secara amnya anda boleh menetapkan nilai sebelum sintaks cuba.

Untuk keperluan sambungan seperti ini, fungsi pengurus konteks biasanya digunakan.