Pandas

读取文件-------------------------------------------------------------------------------

df = pd.read_excel(xxxxxxxxxxxxxxxx,index_col=False)
df = pd.read_csv("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.csv")
data_power= pd.read_csv(xxxxxxxx, encoding='gbk', sep=',')  # 列以','为分隔符分隔列   有中文编码可以用gbk
data_r  = pd.read_csv(xxxxxxxxxxxx, encoding='gbk', sep=' ')  # 列以' '为分隔符 



修改字段名---------------------------------------------------------------------------------
df1.rename(columns={
            "Date_Time":"times",
            }, inplace=True)    

遍历dataframe----------------------------------------------------------------------------
for index, row in df1.iterrows():

    if "_" in str(df1["times"].iloc[index]):

        df1["times"].iloc[index] = str(df1["times"].iloc[index]).replace('_',' ')


对每一行的值进行修改
for index, row in data_airia.iterrows():

    start = datetime.datetime.strptime(str(data_airia["起报时刻"].iloc[index]).split(' ')[0].replace('/','-'), "%Y-%m-%d")
    stop = datetime.datetime.strptime(str(data_airia["预报时刻"].iloc[index]).split(' ')[0].replace('/','-'), "%Y-%m-%d")

    data_airia["预报时刻"].iloc[index] = datetime.datetime.strptime(str(data_airia["预报时刻"].iloc[index]),
                                                                 "%Y/%m/%d %H:%M:%S").strftime("%Y-%m-%d %H:%M:%S")
    
    data_airia["forecastorder"].iloc[index] = int((stop-start).days)
    data_airia["起报时刻"].iloc[index] = str(data_airia["起报时刻"].iloc[index]).replace('/' ,'-')
    data_airia["预报时刻"].iloc[index] = str(data_airia["预报时刻"].iloc[index]).replace('/', '-')

取值--------------------------------------------------------------------------------------
df. loc[行][列]
df[列].iloc[行]


删除某几列---------------------------------------------------------------------------------
new_df.drop(list(new_df)[0:1], axis=1, inplace=True)
df_2 = df2_sheet.drop(columns=['实发功率', "实测辐照度"])
new_data.drop([0], axis=0, inplace=True)  # 删除第一行



两个dataframe上下连接---------------------------------------------------------------------------
weather_df = pd.concat(weather_df_list, axis=0,ignore_index=True)


dataframe 横向连接-----------------------------------------------------------------------------
data = pd.merge(weather_df, power_df, how='left', on='date_time', sort=False)
data.sort_values(by='date_time', inplace=True)




dataframe写入excel---------------------------------------------------------------------------------
writer = pd.ExcelWriter(os.path.join(base_path, 'total.xlsx'))

data_total.to_excel(writer, index=False)

writer.save()

拷贝dataframe-------------------------------------------------------------------------------------------
data_total = file_data.copy()

df的列名列表----------------------------------------------------------------------------------------------
　　column_list = list(df.columns)