删除csv中的特定字符数

import csv

def delete_characters(csv_file, column_index, num_characters):
    with open(csv_file, 'r') as file:
        reader = csv.reader(file)
        rows = list(reader)
        
    for row in rows:
        if len(row) > column_index:
            cell = row[column_index]
            if len(cell) > num_characters:
                row[column_index] = cell[:-num_characters]
    
    with open(csv_file, 'w', newline='') as file:
        writer = csv.writer(file)
        writer.writerows(rows)

delete_characters('data.csv', 2, 3)