Question

我有一个CSV文件，其记录超过100k，在该记录中，一列的值以逗号分隔，我想对逗号分隔值进行排序。

示例数据：

"PT3QB789TSUIDF371261","THE TORONTO,DOMINION BANK","HZSN7FQBPO5IEWYIGC72","MAS,CA.ON.OSC,ASIC*,AAAA","XVCCCCCCCCCCYYUUUUU"
"11111111111111111111","ABC,XYZ,QWE","HZSN7FQBPO5IEWYIGC72","POU,ABC,MAS,CA.QC.OSC,CA.ON.OSC","XVRRRRRRRRTTTTTTTTTTTTT"
"22222222222222222222","BHC,NBC,MKY","HZSN7FQBPO5IEWYIGC72","BVC,AZX,CA.SK.FCAA,CA.NL.DSS","QQQQQQQQQRRCGHDKLKSLS"

正如您所看到的那样，第2列和第4列具有逗号分隔值，但我只想对第4列值进行排序。所以我的输出应该如下所示：

"PT3QB789TSUIDF371261","THE TORONTO,DOMINION BANK","HZSN7FQBPO5IEWYIGC72","AAAA,ASIC*,CA.ON.OSC,MAS","XVCCCCCCCCCCYYUUUUU"
"11111111111111111111","ABC,XYZ,QWE","HZSN7FQBPO5IEWYIGC72","ABC,CA.ON.OSC,CA.QC.OSC,MAS,POU","XVRRRRRRRRTTTTTTTTTTTTT"
"22222222222222222222","BHC,NBC,MKY","HZSN7FQBPO5IEWYIGC72","AZX,BVC,CA.NL.DSS,CA.SK.FCAA","QQQQQQQQQRRCGHDKLKSLS"

我想写的代码如下：

 #!/usr/bin/python

import csv

OUT_FILE = '/proj/ctc/temp/sanjay/REC-754/2017-05-29_IR_Position_Report_US_US_2017-05-30_out.csv'
IN_FILE = '/proj/ctc/temp/sanjay/REC-754/2017-05-29_IR_Position_Report_US_US_2017-05-30.csv'

f = open(IN_FILE, 'r')
o = open(OUT_FILE,'w')

with f:
 reader = csv.reader(f)
with o:
 writer = csv.writer(o)
 for row in reader:
    reportable_jurisdiction=row[68]
    if ',' in reportable_jurisdiction:
        row[68]=sorted(list(row[68].split(',')))
        print " reportable Jurisdiction with comma "+reportable_jurisdiction
    else:
        print "reportable Jurisdiction if single "+reportable_jurisdiction

        if(f.closed):
            f=open(IN_FILE,"r") 
        if(o.closed):
            o=open(OUT_FILE,"w")
    writer.writerow(row)
    print(row)

但是当我执行这个python脚本时，我得到以下错误：

$./Csvreader2.py
Traceback (most recent call last):
  File "./Csvreader2.py", line 15, in <module>
    for row in reader:
ValueError: I/O operation on closed file

我摆脱了这个问题，问题在于缩进代码但是我得到了新的问题

Traceback (most recent call last):
  File "./Csvreader2.py", line 14, in <module>
    reportable_jurisdiction=row[68]
IndexError: list index out of range

在我的CSV文件中有超过100列，但为什么会出现此错误？

Answer 1

您正在将这些文件用作上下文管理器：

with f:
    # ...
with o:
    # ...

with块结束后（后续代码的缩进级别低于或等于with语句缩进），文件已关闭且不能再读一遍。这意味着文件f在with o:行执行时关闭。

但是，您需要f保持打开状态，以便您可以通过csv.reader对象继续阅读它。将所有代码放在一个 with语句下，同时保持两个文件同时打开：

with f, o:
    reader = csv.reader(f)
    writer = csv.writer(o)
    for row in reader:
        # ...

ValueError：关闭文件的I / O操作

1 个答案: