IndexError: list index out of range 现在我已经改变了文件的读取方式

Posted 2023-02-23

【中文标题】IndexError: list index out of range 现在我已经改变了文件的读取方式

【英文标题】：IndexError: list index out of range is thrown now that i've changed the way the file is read

【发布时间】：2018-11-15 04:46:35

【问题描述】：

我正在尝试读取并重新格式化一个非常大 (2GB+) 的 .out 文件，该文件的结构类似于 csv。我之前使用的是标准的 open()，没有出现这样的问题，但将其更改为 codecs.open()，因为它遇到了一些字符问题。

现在开始扔了

Traceback (most recent call last): line 21, in <module> if(r[5]==""): IndexError: list index out of range 在第一行，尽管在 r[5] 处肯定有一个元素。 （运行时间为 0.301s）

import sys
import csv
import datetime
import codecs
maxInt=sys.maxsize
decrement=True

while decrement:
    decrement=False
    try:
        csv.field_size_limit(maxInt)
    except OverflowError:
        maxInt = int(maxInt/10)
        decrement = True

with codecs.open("file.out", 'rU', 'utf-16-be') as source:
    rdr = csv.reader(source)
    with open("out.csv","w", newline='') as result:
        wtr = csv.writer(result)
        wtr.writerow(("Column1", "column2", "column3", "etc..."))
        for r in rdr:
            if(r[5]==""):
                continue
            wtr.writerow((datetime.datetime.strptime(r[5], '%m/%d/%Y').strftime('%Y-%m-%d'), r[3], r[7], r[9]+r[10]+" "+r[12]))

使用 utf-8 抛出 UnicodeDecodeError: 'utf-8' codec can't decode byte 0xc9 in position 12: invalid continuation byte

使用 latin-1 或 ISO-8859-1 会抛出 UnicodeEncodeError: 'charmap' codec can't encode characters in position 57-58: character maps to <undefined>，尽管在运行更多之后。

输入文件如下所示：

"A00017","K","G","1999","4530","01/12/1999","","","","PEOPLE TO ELECT MANGINELLI","","","","258 MAGNIOLIA DRIVE","SELDEN","NY","11784","","","404.57","","","","","","","2","","NAA","07/22/1999 08:43:59"
"A00037","K","G","1999","999999","01/12/1999","","","","CITIZENS TO ELECT TEDISCO TO ASSEMBLY","","","","","","","","","","0","","","","","","","2","","",""
"A00037","K","N","1999","1693","01/15/1999","","","","OUTSTANDING LOAN","","","","2176 GUILDERLAND AVE","SCHENECTADY","NY","12306","","","10474.8","10474.8","","","OTHER","","PREVIOUS LOAN FROM JAMES TEDISCO","","P","JM","07/15/1999 15:08:17"
"A00037","J","N","2000","1694","01/13/2000","","","","OUTSTANDING LOAN","","","","2176 GUILDERLAND","SCHENECTADY","NY","12306","","","10474.8","10474.8","","","OTHER","","LOANS FROM PREVIOUS CAMPAIGNS FROM J","","P","JM","01/14/1900 16:35:09"
"A00037","K","X","2000","999999","","","","","","","","","","","","","","","","","","","","","","","","","07/20/2000 00:00:00"
"A00037","J","X","2001","999999","","","","","","","","","","","","","","","","","","","","","","","","","01/17/2001 00:00:00"
"A00037","K","X","2002","999999","","","","","","","","","","","","","","","","","","","","","","","","","07/19/2002 00:00:00"
"A00037","J","X","2003","999999","","","","","","","","","","","","","","","","","","","","","","","","","01/21/2003 00:00:00"
"A00037","K","X","2003","999999","","","","","","","","","","","","","","","","","","","","","","","","","07/16/2003 00:00:00"
"A00037","J","X","2004","999999","","","","","","","","","","","","","","","","","","","","","","","","","01/22/2004 00:00:00"

感谢：

"Line contains NULL byte" in CSV reader (Python)

_csv.Error: field larger than field limit (131072)

【问题讨论】：

你能在你的循环中打印r吗？

没有看到重现问题的文件，我们很难为您提供帮助。

【参考方案1】：

在您正在读取的“file.out”中，找出行中每个单元格的元素之间的分隔符。像 '\t'-tab 或 ','-comma 并将其传递给 'delimiter' 属性。

尝试打印 'r' 并查看列名之间的字符或行中的值

rdr = csv.reader(source,delimiter=<separator>)

【讨论】：

你试过打印 'r' 看看它是不是一个数组吗？

尝试将 r 打印到控制台并得到 UnicodeEncodeError: 'charmap' codec can't encode characters in position 2-97: character maps to <undefined>

在 codecs.open("file.out", 'rU', 'utf-8') 中使用 'utf-8'

你可以尝试使用'latin-1'或'ISO-8859-1'编码而不是'utf-8'

你能试试这个代码吗：rdr = csv.reader((line.replace('\0','') for line in source),delimiter=',') 你也可以分享导致错误的数据行