python 中有没有办法删除 csv 文件中的几行？

Question

我目前正在从 sec.gov 下载 2016 年第一季度的 form.idx 文件。由于我只对 10-Ks 感兴趣，我想将文件下载为 .csv 文件并删除无用的行。 我尝试按表单类型进行过滤，但没有成功。

到目前为止，我的代码如下：

import requests
import os

years = [2016]

quarters = ['QTR1']

base_path = '/Users/xyz/Desktop'

current_dirs = os.listdir(path=base_path)

for yr in years:
    if str(yr) not in current_dirs:
        os.mkdir('/'.join([base_path, str(yr)]))
    
    current_files = os.listdir('/'.join([base_path, str(yr)]))
    
    for qtr in quarters:
        local_filename =  f'{yr}-{qtr}.csv'
        
    
        local_file_path = '/'.join([base_path, str(yr), local_filename])
        
        if local_filename in current_files:
            print(f'Skipping file for {yr}, {qtr} because it is already saved.')
            continue
        
        url = f'https://www.sec.gov/Archives/edgar/full-index/{yr}/{qtr}/form.idx'
        
        r = requests.get(url, stream=True)
        with open(local_file_path, 'wb') as f:
            for chunk in r.iter_content(chunk_size=128):
                f.write(chunk)

r2 = pd.read_csv('/Users/xyz/Desktop/2016-QTR1.csv', sep=";", encoding="utf-8")
r2.head()
filt = (r2 ['Form Type'] == '10-K')
r2_10K = r2.loc[filt]
r2_10K.head()
r2_10K.to_csv('/Users/xyz/Desktop/modified.csv')

The Error message I get is:
Traceback (most recent call last):

  File "<ipython-input-5-f84e3f81f3d1>", line 61, in <module>
    filt = (r2 ['Form Type'] == '10-K')

  File "/Users/xyz/opt/anaconda3/envs/spyder-4.1.5_1/lib/python3.8/site-packages/pandas/core/frame.py", line 2906, in __getitem__
    indexer = self.columns.get_loc(key)

  File "/Users/xyz/opt/anaconda3/envs/spyder-4.1.5_1/lib/python3.8/site-packages/pandas/core/indexes/base.py", line 2897, in get_loc
    raise KeyError(key) from err

KeyError: 'Form Type'

也许有一种方法可以删除文件中我不需要的行？ 否则，我也很感谢在这个问题上提供的任何帮助。

提前谢谢了。

亲切的问候，埃琳娜

Answer 1

您可以通过多种方式从 csv 文件中删除行。 Python 中的 Pandas 库具有任意数量的函数，您可以通过这些函数更改 csv 文件中的数据。 首先通过以下代码导入 Pandas 库：

import pandas as pd

通过以下代码读取您的 csv 文件：

df = pd.read_csv("filename.csv")

例如，如果您有一个名为 df 的数据字段，其中包含您的 csv 文件。 您可以通过以下代码按索引删除行：

df1 = df.drop([df.index[1], df.index[2]])

您可以通过多种方式使用 Pandas 从 csv 中删除行。 例如：按行值、按 null 值、按数据类型等等！

Answer 2

这是您的完整工作代码，主要问题是您从网上获得的 csv 格式，完整代码： https://rextester.com/QUGF24653

我做了什么：

1. 我确实跳过了前 10 行
2. 使用 3 个空格分隔符后设置列名
3. 将最后一列拆分为 2 个新列
4. 带有“10-K”的过滤器表单类型

import requests import os import pandas as pd years = [2016] quarters = ['QTR1'] base_path = '/Users/xyz/Desktop' current_dirs = os.listdir(path=base_path) for yr in years: if str(yr) not in current_dirs: os.mkdir('/'.join([base_path, str(yr)])) current_files = os.listdir('/'.join([base_path, str(yr)])) for qtr in quarters: local_filename = f'{yr}-{qtr}.csv' local_file_path = '/'.join([base_path, str(yr), local_filename]) if local_filename in current_files: print(f'Skipping file for {yr}, {qtr} because it is already saved.') continue url = f'https://www.sec.gov/Archives/edgar/full-index/{yr}/{qtr}/form.idx' r = requests.get(url, stream=True) with open(local_file_path, 'wb') as f: for chunk in r.iter_content(chunk_size=128): f.write(chunk) colnames=['Form Type', 'Company Name', 'CIK', 'Date Filed','File Name'] r2 = pd.read_csv('/Users/xyz/Desktop/2016-QTR1.csv', sep=r'\s{3,}', skiprows=10, encoding="utf-8", names=colnames,header=None) r2[['Date Filed','File Name']] = r2['Date Filed'].str.split(expand=True) filtered = (r2['Form Type'] == '10-K') r2_10K = r2.loc[filtered] print(r2_10K.head())

Output：

   Form Type                            Company Name      CIK  Date Filed                                    File Name
2181      10-K                       1347 Capital Corp  1606163  2016-03-21  edgar/data/1606163/0001144204-16-089184.txt
2182      10-K  1347 Property Insurance Holdings, Inc.  1591890  2016-03-17  edgar/data/1591890/0001387131-16-004603.txt
2183      10-K                1ST CONSTITUTION BANCORP  1141807  2016-03-22  edgar/data/1141807/0001141807-16-000010.txt
2184      10-K                         1ST SOURCE CORP    34782  2016-02-19    edgar/data/34782/0000034782-16-000102.txt
2185      10-K            1st Century Bancshares, Inc.  1420525  2016-03-04  edgar/data/1420525/0001437749-16-026765.txt