[ python-Bugs-1431091 ] CSV Sniffer fails to report mismatch of column counts

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Bugs item #1431091, was opened at 2006-02-13 23:47
Message generated for change (Comment added) made by tekkaman
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Category: Extension Modules
Group: Python 2.4
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Vinko (vvrsalob)
Assigned to: Andrew McNamara (andrewmcnamara)
Summary: CSV Sniffer fails to report mismatch of column counts

Initial Comment:
If one line of a CSV file is missing one or more
commas, the delimiter detection code of the Sniffer
class fails, setting delimiter to an empty string.

This leads to a totally misleading error when using
has_header(). 

This code shows the problem (Python 2.4.2, FC3 and
Ubuntu Breezy):

import csv

str1 = "a,b,c,d\r\n1,2,foo bar,dead
beef\r\nthis,line,is,ok\r\n"
str2 = "a,b,c,d\r\n1,2,foo bar,dead beef\r\nthis,line
is,not\r\n"

s = csv.Sniffer()

d1 = s.sniff(str1)
d2 = s.sniff(str2)

for line in str1.split('\r\n'):
    print line.count(',')

print d1.delimiter
print s.has_header(str1)

for line in str2.split('\r\n'):
    print line.count(',')

print d2.delimiter
print s.has_header(str2)


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Comment By: Simone Leo (tekkaman)
Date: 2007-04-11 17:59

Message:
Logged In: YES 
user_id=891539
Originator: NO

Problem is still there as of Python 2.4.3.

Trying to read in a file whose lines have a different number of fields, I
get:

Traceback (most recent call last):
  File "../myscript.py", line 59, in ?
    main()
  File "../myscript.py", line 30, in main
    reader = csv.reader(fin, dialect)
TypeError: bad argument type for built-in operation

where "dialect" has been sniffed by feeding the first two lines to the
Sniffer.

What I expect is to either:
  1. get different sized rows, with no exception raised
  2. get a csv.Error instead of the TypeError above

Thanks

----------------------------------------------------------------------

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