comparing dialects of csv-module

[Malte Dik]

Hi out there!

I want to put some intelligence into a csv reading script and in order to do
so I want to compare possible different dialects I collect with some random

d = csv.Sniffer().sniff("1,2,3,4"),

because the csv is kinda dirty.

Now sniff() returns a class object and those aren't comparable in the "if
dialect_1 == dialect_2: count something" sense.

Has anyone around here already dealt with this kind of problem and maybe
even a solution I could utilize? That would be great.

If not - I guess I would just write a quick function comparing the
attributes of those dialects ... - but just out of educational curiosity:
Would it be the right way to implement an __eq__(...) function into the
Dialect class or how would someone who would want to make it right do it?


Sincerest greetings,

Malte

 

[Peter Otten]

Hi out there!

I want to put some intelligence into a csv reading script and in order to
do so I want to compare possible different dialects I collect with some
random

d = csv.Sniffer().sniff("1,2,3,4"),

because the csv is kinda dirty.

Now sniff() returns a class object and those aren't comparable in the "if
dialect_1 == dialect_2: count something" sense.

Has anyone around here already dealt with this kind of problem and maybe
even a solution I could utilize? That would be great.

An implementation for the lazy

import csv
d = csv.Sniffer().sniff("1,2,3")
def eq(a, b, attributes=[name for name in dir(d) if not

name.startswith("_")]):
.... return all(getattr(a, n, None) == getattr(b, n, None) for n in
attributes)
....True

If not - I guess I would just write a quick function comparing the
attributes of those dialects ... - but just out of educational curiosity:
Would it be the right way to implement an __eq__(...) function into the
Dialect class or how would someone who would want to make it right do it?

I don't know if you can do it for classic classes; for newstyle classes
you'd have to reimplement comparison in the metaclass:
.... class __metaclass__(type):
.... def __eq__(self, other):
.... return self._key() == other._key()
.... def __ne__(self, other):
.... return self._key() != other._key()
.... def _key(self):
.... return self.quotechar, self.delimiter #,...
........ quotechar = "'"
.... delimiter = ":"
........ quotechar = "'"
.... delimiter = ","
....True

On a side note, I think it's a C++ism that dialects are classes rather than
class instances. That's a superfluous complication since in Python no work
will be moved from compile time to runtime anyway.

Peter

 

[Malte Dik]

quote:

An implementation for the lazy

import csv
d = csv.Sniffer().sniff("1,2,3")
def eq(a, b, attributes=[name for name in dir(d) if not

name.startswith("_")]):
... return all(getattr(a, n, None) == getattr(b, n, None) for n in
attributes)
...

Wow, this is awesome. I'd never come up with something like this.


Will digg into it deeper as I implement it (code snippets like this need to
melt in order to effuse all their flavor , but want to thank you very much
in the first place!



Have a nice day everyone,

Malte

 

[Malte Dik]

quote:

d = csv.Sniffer().sniff("1,2,3")
def eq(a, b, attributes=[name for name in dir(d) if not

name.startswith("_")]):
... return all(getattr(a, n, None) == getattr(b, n, None) for n in
attributes)

Only change I made is substituting "dir(csv.excel)" or "dir(csv.Dialect)"
for "dir(d)", because I can't be always sure, that there'd be a nicely
defined "d".


Salute,

Malte