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我是python初学者。我有包含 5 个表的数据库，我使用 python 使用 asammdf 将所有这些表导出到 mdf 文件。

path_data = os.path.join('..\\Data', 'db_2021-05-06_11-49-42_day.db')
con = sqlite3.connect(path_data)
cursor = con.cursor()
cursor.execute('SELECT name FROM sqlite_master WHERE type="table";')
tables = cursor.fetchall()
print(tables)

sigs = []
for equipment in tables:
    df = pd.read_sql_query('select * from' + equipment , con)
    df_small = df[0:1000]
    df_time = (df_small['ts']-df_small.iloc[0]['ts'])
    df_time_int = df_time.astype('int64')
    for signal in df_small.columns.to_list():
        test_signal = Signal(samples=df_small[signal],  timestamps=df_time,
                        name=signal,
                        unit='A')
        sigs.append(test_signal)
mdf.append(sigs)
mdf.save('test_complete.mf4', overwrite=True)

我发现这个错误：

TypeError                                 Traceback (most recent call last)
c:\Users\Muhammad Lazaroni\SW_Workspace\MeasurementMerger\Scripts\merger.py in 
      37 # table_list= list[tables]
      38 for equipment in tables:
----> 39     df = pd.read_sql_query('select * from' + equipment , con)
      40     df_small = df[0:1000]
      41     df_time = (df_small['ts']-df_small.iloc[0]['ts'])

TypeError: can only concatenate str (not "tuple") to str
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1 回答 1

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短语“can only concatenate str (not "tuple") to str”的意思是“试图连接 str 和 non-str (tuple)”。因此，我们需要匹配我们尝试组合的任何一个的类型。

df = pd.read_sql_query('select * from' + str(equipment) , con)

df = pd.read_sql_query('select * from' + equipment , str(con))

尝试其中任何一个。

于 2021-05-17T14:40:00.103 回答