关于pandas通过操作文件操作符读取文件首行时遇到的一点异常

处于业务上的原因，我需要先用pandas读取一下文件首行，再用pyarrow读取剩余的数据。但是在程序运行完后发现少了700多行数据。

import zipFIle
import pandas as pd
from pyarrow import feather as ft, csv as psv

with zipfile.ZipFile(file_path) as zip_file:
    with zip_file.open(zip_file.namelist()[0], pwd=b"abc") as f:
        fcolumns = f.readline().decode("utf-8").split(",")
        first_line = f.readline().decode("utf-8").split(",")
        f.seek(0)


        columns_df = pd.read_csv(f, nrows=0, delimiter=",", index_col=False)
        
        data = psv.read_csv(f)

经过反复测试，发现是因为columns_df = pd.read_csv(f, nrows=0, delimiter=",", index_col=False)这行代码出了问题，虽然我指定了nrows=0，但是实际上文件操作符往后跳跃了700多行。通俗来说就是，虽然我只想用pandas读第一行，但它可能读了700多行，只给我返回一行。

在代码最后加上 f.seek(0)使文件操作符返回文件开头即可

import zipFIle
import pandas as pd
from pyarrow import feather as ft, csv as psv

with zipfile.ZipFile(file_path) as zip_file:
    with zip_file.open(zip_file.namelist()[0], pwd=b"abc") as f:
        fcolumns = f.readline().decode("utf-8").split(",")
        first_line = f.readline().decode("utf-8").split(",")
        f.seek(0)

        columns_df = pd.read_csv(f, nrows=0, delimiter=",", index_col=False)
        
        data = psv.read_csv(f)
        
        # 加这一行代码即可
        f.seek(0)