如何更改多个 CSV 单元格中的值？

Question

我有 118 个 CSV，我需要进入每个 CSV 并将 F1、F2、F3 等更改为 0。

例如，在 csv1 中，F1 = 0，在 csv2 中，F2 = 0，在 csv3 中，F3 = 0 等等。

CSV 包含标题：

Answer 1

我假设您所有的 CSV 文件都具有相同的格式，并且您尝试将列 F 设置为所有这些文件的 0。

您可以使用 Python CSV 库来帮助您，如下所示：

import csv
import glob

for filename in glob.glob('*.csv'):
    print(f'Processing: {filename}')
    
    with open(filename) as f_input:
        csv_input = csv.reader(f_input)
        header = next(csv_input)
        rows = [[*row[:5], '0'] for row in csv_input]

    with open(filename, 'w', newline='') as f_output:
        csv_output = csv.writer(f_output)
        csv_output.writerow(header)
        csv_output.writerows(rows)

这会从给定文件夹中读取所有.csv 文件并将Multi Col 2 值更改为0。它对所有行执行此操作，但标题保持不变。

Answer 2

Mr. Evans 有pretty neat code 使用 Python CSV 库，所以我将对其进行扩展以回答 y 我们的具体问题。

import csv
import glob

file_count = 0

for filename in glob.glob('*.csv'):
    file_count += 1
    print(f'Processing: {filename}')

    with open(filename) as f_input:
        csv_input = csv.reader(f_input)
        header = next(csv_input)
        line_count = 0
        rows = []
        for row in csv_input:
            line_count += 1
            if line_count == file_count:
                rows.append([*row[:5], '0'])
            else:
                rows.append([*row[:6]])        
        
    with open(filename, 'w', newline='') as f_output:
        csv_output = csv.writer(f_output)
        csv_output.writerow(header)
        csv_output.writerows(rows)

注意：代码将针对工作目录中的所有 .csv 文件运行，并将按字母顺序遍历文件。

Answer 3

谢谢大家，我制定了自己的解决方案，它比这里发布的要优雅得多。但我从需要 x 个文件到修改 col/row 的角度自动化了它。

#==============================================================================

# Import the necessary packages
import os
#import glob
import shutil
import pathlib
import pandas as pd
#import numpy as np

#==============================================================================

InputPath = 'F:\\cells\\bc_dbase\\bc_dbase1.csv'

OutputPath = 'F:\\cells\\bc_dbase'

str1 = 'Name '
str2 = 'Mult Col 2'

NoStart = 1
NoEnd = 119

#==============================================================================

# Create complete path of folders
def CreatePath(FullPath,File=False):
    Parts = pathlib.Path(FullPath).parts
    for [n1,Folder] in enumerate(Parts):
        if File==True and n1==len(Parts)-1 and "." in Parts[n1]:
            continue
        elif n1==0:
            FolderPath = Parts[n1]
        else:
            FolderPath = os.path.join(FolderPath,Folder)
        if os.path.exists(FolderPath)==False:
            os.mkdir(FolderPath)

#==============================================================================

# Delete folder
def DeleteFolder(FullPath):
    FullPath = pathlib.Path(FullPath)
    try:
        shutil.rmtree(FullPath)
    except:
        pass

#==============================================================================

CreatePath(OutputPath,File=False)

[FolderPath,File] = os.path.split(InputPath)
[FileName,FileExt] = os.path.splitext(os.path.basename(InputPath))


ReversedFileName = FileName[::-1]
AdjFileName = FileName


for n1 in reversed(range(len(AdjFileName))):
    char = FileName[n1]
    if char.isdigit():
        AdjFileName = AdjFileName[:n1] + AdjFileName[(n1+1):]
    else: break;


Data1 = pd.read_csv(InputPath)
Data2 = pd.DataFrame.copy(Data1)
NameCols = Data1.columns
if str2 in NameCols:
    Data2.loc[:,str2] = 1

for n1 in range(NoStart,NoEnd+1):
    NewFile = AdjFileName + str(n1) + FileExt
    NewFilePath = os.path.join(OutputPath,NewFile)
    Data3 = pd.DataFrame.copy(Data2)
    index = Data3[Data3[str1]==n1].index[0]
    Data3.loc[index,str2] = 0
    
    Data3.to_csv(NewFilePath, index=False)
    print('[INFO] Storing file:',NewFilePath)



                
                
            
#==============================================================================