python之包含额外逗号的 csv 文件的 CSV 模块问题_编程设计

我正在阅读 Clinton W. Brownley (O'Reilly Media Inc.) 的Foundation for Analytics with Python一书

对于第 2 章 - 读取和写入 CSV 文件(第 2 部分) 基本 Python，带有 csv 模块

脚本如下:

#!/usr/bin/env python3 
import sys 
import csv 
 
input_file = sys.argv[1] 
output_file = sys.argv[2] 
 
with open(input_file, 'r', newline='') as csv_input_file: 
    with open(output_file, 'w', newline='') as csv_output_file: 
 
        filereader = csv.reader(csv_input_file, delimiter=',') 
        filewriter = csv.writer(csv_output_file, delimiter=',') 
 
        for row_list in filereader: 
            print(row_list) 
            filewriter.writerow(row_list)

输入文件的字段包含逗号(最后两行中的美元金额):

Supplier Name,Invoice Number,Part Number,Cost,Purchase Date 
Supplier X,001-1001,2341,$500.00,1/20/14 
Supplier X,001-1001,2341,$500.00,1/20/14 
Supplier X,001-1001,5467,$750.00,1/20/14 
Supplier X,001-1001,5467,$750.00,1/20/14 
Supplier Y,50-9501,7009,$250.00,1/30/14 
Supplier Y,50-9501,7009,$250.00,1/30/14 
Supplier Y,50-9505,6650,$125.00,2/3/14 
Supplier Y,50-9505,6650,$125.00,2/3/14 
Supplier Z,920-4803,3321,$615.00,2/3/14 
Supplier Z,920-4804,3321,$615.00,2/10/14 
Supplier Z,920-4805,3321,$6,015.00,2/17/14 
Supplier Z,920-4806,3321,$1,006,015.00,2/24/14

运行脚本在终端中产生以下输出:

['Supplier Name', 'Invoice Number', 'Part Number', 'Cost', 'Purchase Date'] 
['Supplier X', '001-1001', '2341', '$500.00', '1/20/14'] 
['Supplier X', '001-1001', '2341', '$500.00', '1/20/14'] 
['Supplier X', '001-1001', '5467', '$750.00', '1/20/14'] 
['Supplier X', '001-1001', '5467', '$750.00', '1/20/14'] 
['Supplier Y', '50-9501', '7009', '$250.00', '1/30/14'] 
['Supplier Y', '50-9501', '7009', '$250.00', '1/30/14'] 
['Supplier Y', '50-9505', '6650', '$125.00', '2/3/14'] 
['Supplier Y', '50-9505', '6650', '$125.00', '2/3/14'] 
['Supplier Z', '920-4803', '3321', '$615.00', '2/3/14'] 
['Supplier Z', '920-4805', '3321', '$615.00', '2/17/14'] 
['Supplier Z', '920-4804', '3321', '$6', '015.00', '2/10/14'] 
['Supplier Z', '920-4806', '3321', '$1', '006', '015.00', '2/24/14']

但是这本书显示了这样的预期输出:

我做错了什么？

请您参考如下方法:

您可以通过三种方式来更正您的输出:

从金额中删除逗号。
使用引号:将金额用双引号引起来。例如，第一行 $500.00 将是“$500.00”。引用是一种流行的技术。使用引用时，将您的阅读语句更改为:

filereader = csv.reader(csv_input_file, delimiter=',', quotechar='"')
使用不同的分隔符。您不必使用逗号作为分隔符。要使用此方法，请将输入文件中的分隔符更改为另一个分隔符。我喜欢管道分隔的文件，因为管道很少用作文本。

filereader = csv.reader(csv_input_file, delimiter='|')