Pandas 在合并多个 CSV 文件后向输出文件添加标题

Question

import pandas as pd
import os

file1 = 'https://public.fyers.in/sym_details/NSE_CM.csv'
file2 = 'https://public.fyers.in/sym_details/NSE_FO.csv'
file3 = 'https://public.fyers.in/sym_details/BSE_CM.csv'
CHUNK_SIZE = 10 ** 6
csv_file_list = [file1, file2, file3]
output_file = "/content/output.csv"

for csv_file_name in csv_file_list:
  skipRows = [2022,92805]
  chunk_container = pd.read_csv(csv_file_name, chunksize=CHUNK_SIZE, skiprows=skipRows)
  for chunk in chunk_container:
    headerList =["fytoken", "symbol", "instrumentType","lotSize","tickSize","ISIN","tradingSession","lastUpdate","expiryDate","symbolTicker","exchange","segment","scripCode","scripName","scripToken","strikePrice","optionType"]
    chunk.to_csv(output_file,header=headerList, mode="a", index=False)

---

我想合并三个 CSV 文件并将标题添加到输出文件。 但它在每个 CSV 的开头（在输出文件中）返回带有标题的输出文件。

Answer 1

您正在阅读块中的内容并为每个块附加header 。

相反，请尝试以下操作：

import pandas as pd

file1 = 'https://public.fyers.in/sym_details/NSE_CM.csv'
file2 = 'https://public.fyers.in/sym_details/NSE_FO.csv'
file3 = 'https://public.fyers.in/sym_details/BSE_CM.csv'
CHUNK_SIZE = 10 ** 6
csv_file_list = [file1, file2, file3]
output_file = "./content/output.csv"

headerList = ["fytoken", "symbol", "instrumentType", "lotSize", "tickSize", "ISIN", "tradingSession",
              "lastUpdate", "expiryDate", "symbolTicker", "exchange", "segment", "scripCode", "scripName",
              "scripToken", "strikePrice", "optionType"]

df = pd.DataFrame(columns=headerList)
df.to_csv(output_file, index=False)

for csv_file_name in csv_file_list:
    skipRows = [2022, 92805]
    with pd.read_csv(csv_file_name, chunksize=CHUNK_SIZE, skiprows=skipRows) as chunk_container:
        for chunk in chunk_container:
            chunk.to_csv(output_file, header=None, mode="a", index=False)

在这里，我们预先创建了一个只有headers的 csv 文件，并将从上述 URL 读取的数据附加到同一个文件中。