Pierre GM writes:
> On Nov 11, 2010, at 8:31 PM, Lluís wrote:
>> Pierre GM writes:
>>
>>> In practice, that's exactly what happens below the hood when
>>> genfromtxt tries to guess the output type of the converter. It tries a
>>> single value ('1'), fails, and decides that the result must be an
>>> object... Probably not the best strategy, as it crashes in your
>>> case. But yours is a buggy case anyway.
>> [...]
>>> Now, we can argue over the very last point: if both a converter and a
>>> dtype are specified, which one should take precedence?
>>> You have my opinion, let's hear yours.
>>
>> What about delaying the calculation of converters?
>> Instead of using type
>> checks with fake data, 'StringConverter.update' could take an optional
>> argument 'imput_sample' (defaulting to "1") in order to perform its
>> checks.
>>
>> Then, use real data from the first (non-comment, non-names) line of the
>> input file when calling 'StringConverter.update' in 'genfromtxt'.
> Mmh. That's an idea... Do you have a patch to suggest?
This will work as long as 'first_values' is assured to always contain
valid data and as long as its indexes are equivalent to those in
converters (which I simply haven't checked).
--- numpy/lib/_iotools.py.bak 2010-11-14 21:17:12.000000000 +0100
+++ numpy/lib/_iotools.py 2010-11-14 21:19:02.000000000 +0100
@@ -672,7 +672,7 @@
self._status = _status
self.iterupgrade(value)
- def update(self, func, default=None, missing_values='', locked=False):
+ def update(self, func, default=None, missing_values='', locked=False, input_sample='1'):
"""
Set StringConverter attributes directly.
@@ -689,6 +689,7 @@
locked : bool, optional
Whether the StringConverter should be locked to prevent automatic
upgrade or not. Default is False.
+ input_sample : A sample input to test the validity of `func`.
Notes
-----
@@ -705,7 +706,7 @@
self.type = self._getsubdtype(default)
else:
try:
- tester = func('1')
+ tester = func(input_sample)
except (TypeError, ValueError):
tester = None
self.type = self._getsubdtype(tester)
--- numpy/lib/io.py.bak 2010-11-14 21:14:05.000000000 +0100
+++ numpy/lib/io.py 2010-11-14 21:24:37.000000000 +0100
@@ -1235,7 +1235,8 @@
continue
converters[i].update(conv, locked=True,
default=filling_values[i],
- missing_values=missing_values[i],)
+ missing_values=missing_values[i],
+ input_sample=first_values[i])
uc_update.append((i, conv))
# Make sure we have the corrected keys in user_converters...
user_converters.update(uc_update)
apa!
--
"And it's much the same thing with knowledge, for whenever you learn
something new, the whole world becomes that much richer."
-- The Princess of Pure Reason, as told by Norton Juster in The Phantom
Tollbooth
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