Python 数据帧创建问题

以下函数用于加载数据。城市数据[城市] 映射到用户定义的城市对应的.csv文件

然而，当我“打印（df）”时，我在所有阶段都会得到一个空的数据帧。不知道这里发生了什么

def load_data(city, month, day):
    """
    Loads data for the specified city and filters by month and day if applicable.

    Args:
        (str) city - name of the city to analyze
        (str) month - name of the month to filter by, or "all" to apply no month filter
        (str) day - name of the day of week to filter by, or "all" to apply no day filter
    Returns:
        df - Pandas DataFrame containing city data filtered by month and day
    """
    print (CITY_DATA[city])
    df = pd.read_csv(CITY_DATA[city])
    print (df)
    df['Start Time'] = pd.to_datetime(df['Start Time'])
    df['month'] = df['Start Time'].dt.month
    df['day_of_week'] = df['Start Time'].dt.weekday_name

    if month != 'all':
        months = ['january', 'february', 'march', 'april', 'may', 'june']
        month = months.index(month) + 1
        df = df[df['month'] == month]

    if day != 'all':
        df = df[df['day_of_week'] == day.title()]

    print (df)
    return df

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任何帮助都将不胜感激

只是想澄清一下：什么时候你得到一个空的df，只是在返回语句之前，还是已经在开始的时候（在读取CSV文件之后）？在读取CSV文件之后，你确定文件存在并且有你想要的内容吗？您可以尝试

print（open（CITY_DATA[CITY]））

（或类似的方法），以查看Python是否能够正确地查找和读取该文件。