Python 中的错误：未定义名称“df”

Question

我是 python 的新手，在 stackoverflow 中用谷歌搜索和搜索了很多小时。但是我的代码仍然有问题。我需要在时间间隔内运行 foo 函数，并填充数据帧（例如，每秒向 df 添加时间戳）。我仍然遇到错误消息： NameError: name ‘df’ is not defined

谢谢您的回答。

代码：

     WAIT_TIME_SECONDS = 1

class ProgramKilled(Exception):
    pass

    df = pd.DataFrame([])

############################################################
############################################################
def foo():

    global df
    time1 = str(datetime.now())
    time2 = time1.replace(":", "_")
    print(time2)

    df2 = pd.DataFrame(data= {
    'timestamp': [time2],
    'cas_zapas_1_text': ['cas']
    })

    df = df.append(df2)

############################################################
############################################################
def signal_handler(signum, frame):
    raise ProgramKilled

class Job(threading.Thread):
    def __init__(self, interval, execute, *args, **kwargs):
        threading.Thread.__init__(self)
        self.daemon = False
        self.stopped = threading.Event()
        self.interval = interval
        self.execute = execute
        self.args = args
        self.kwargs = kwargs

    def stop(self):
                self.stopped.set()
                self.join()
    def run(self):
            while not self.stopped.wait(self.interval.total_seconds()):
                self.execute(*self.args, **self.kwargs)

if __name__ == "__main__":
    signal.signal(signal.SIGTERM, signal_handler)
    signal.signal(signal.SIGINT, signal_handler)
    job = Job(interval=timedelta(seconds=WAIT_TIME_SECONDS), execute=foo)
    job.start()

    while True:
          try:
              time.sleep(1)
          except ProgramKilled:
              print("Program killed: running cleanup code")
              job.stop()
              break

这是脚本的结果：

 runfile('C:/Users/Miro/.spyder-py3/untitled8.py', wdir='C:/Users/Miro/.spyder-py3')
Exception in thread Thread-8:
Traceback (most recent call last):
  File "C:\Users\Miro\Anaconda3\envs\spyder_4_0_1\lib\threading.py", line 932, in _bootstrap_inner
    self.run()
  File "C:\Users\Miro\.spyder-py3\untitled8.py", line 90, in run
    self.execute(*self.args, **self.kwargs)
  File "C:\Users\Miro\.spyder-py3\untitled8.py", line 68, in foo
    df = df.append(df2)
NameError: name 'df' is not defined
2020-06-16 08_29_31.920157
Program killed: running cleanup code

原文由 314mip 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

定义 global df 之前 class ProgramKilled(Exception):

原文由 Osadhi Virochana 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 2

谢谢大家的帮助和快速的回答。此解决方案有效：

     WAIT_TIME_SECONDS = 1

global df
df = pd.DataFrame([])

class ProgramKilled(Exception):
    pass

############################################################
############################################################
def foo():

    global df
    time1 = str(datetime.now())
    time2 = time1.replace(":", "_")
    print(time2)

    df2 = pd.DataFrame(data= {
    'timestamp': [time2],
    'cas_zapas_1_text': ['cas']
    })

    df = df.append(df2)

############################################################
############################################################
def signal_handler(signum, frame):
    raise ProgramKilled

class Job(threading.Thread):
    def __init__(self, interval, execute, *args, **kwargs):
        threading.Thread.__init__(self)
        self.daemon = False
        self.stopped = threading.Event()
        self.interval = interval
        self.execute = execute
        self.args = args
        self.kwargs = kwargs

    def stop(self):
                self.stopped.set()
                self.join()
    def run(self):
            while not self.stopped.wait(self.interval.total_seconds()):
                self.execute(*self.args, **self.kwargs)

if __name__ == "__main__":
    signal.signal(signal.SIGTERM, signal_handler)
    signal.signal(signal.SIGINT, signal_handler)
    job = Job(interval=timedelta(seconds=WAIT_TIME_SECONDS), execute=foo)
    job.start()

    while True:
          try:
              time.sleep(1)
          except ProgramKilled:
              print("Program killed: running cleanup code")
              job.stop()
              break

原文由 314mip 发布，翻译遵循 CC BY-SA 4.0 许可协议