Re: New to PSF
Yeah, I mean Python Software Foundation. I am a developer and I'm want to contribute. So, Can you please help me in getting started ? Thanks On Sunday, December 28, 2014 4:27:54 AM UTC+5:30, Steven D'Aprano wrote: > prateek pandey wrote: > > > Hey, I'm new to PSF. Can someone please help me in getting started. > > > Can we have some context? What do you mean by PSF? The Python Software > Foundation? Something else? > > > -- > Steven -- https://mail.python.org/mailman/listinfo/python-list
Re: New to PSF
Yeah, I mean Python Software Foundation. I am a developer and I want to contribute. So, Can you please help me in getting started ? Thanks On Sunday, December 28, 2014 4:27:54 AM UTC+5:30, Steven D'Aprano wrote: > prateek pandey wrote: > > > Hey, I'm new to PSF. Can someone please help me in getting started. > > > Can we have some context? What do you mean by PSF? The Python Software > Foundation? Something else? > > > -- > Steven -- https://mail.python.org/mailman/listinfo/python-list
Re: New to PSF
On Dec 28, 2014, at 09:54, prateek pandey wrote: > Yeah, I mean Python Software Foundation. I am a developer and I want to > contribute. So, Can you please help me in getting started ? https://www.python.org/psf/volunteer/ -- "You can't actually make computers run faster, you can only make them do less." - RiderOfGiraffes -- https://mail.python.org/mailman/listinfo/python-list
CSV Error
Hello,
I am trying to read a csv file using DictReader. I am getting error -
Traceback (most recent call last):
File "", line 1, in
r.fieldnames
File "/usr/lib/python2.7/csv.py", line 90, in fieldnames
self._fieldnames = self.reader.next()
ValueError: I/O operation on closed file
Here is my code in a Python shell -
>>> with open('x.csv','rb') as f:
... r = csv.DictReader(f,delimiter=",")
>>> r.fieldnames
I have tried to open the file in 'rU', 'r' mode. But still I am getting
the above error.
Please help.
Thanks.
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Re: CSV Error
> ValueError: I/O operation on closed file
>
> Here is my code in a Python shell -
>
> >>> with open('x.csv','rb') as f:
> ... r = csv.DictReader(f,delimiter=",")
> >>> r.fieldnames
The file is only open during the context of the with statement. Indent the
last line to match the assignment to r and you should be fine.
Skip
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Re: CSV Error
Skip Montanaro writes:
> > ValueError: I/O operation on closed file
> >
> > Here is my code in a Python shell -
> >
> > >>> with open('x.csv','rb') as f:
> > ... r = csv.DictReader(f,delimiter=",")
> > >>> r.fieldnames
>
> The file is only open during the context of the with statement.
> Indent the last line to match the assignment to r and you should be
> fine.
Or, don't use "with" when experimenting in the shell.
>>> import csv
>>> f = open('x.csv')
>>> r = csv.DictReader(f, delimiter = ',')
>>> r.fieldnames
['Foo', 'Bar']
>>>
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Re: CSV Error
On Sun, 28 Dec 2014 06:19:58 -0600, Skip Montanaro wrote:
>> ValueError: I/O operation on closed file
>>
>> Here is my code in a Python shell -
>>
>> >>> with open('x.csv','rb') as f:
>> ... r = csv.DictReader(f,delimiter=",")
>> >>> r.fieldnames
>
> The file is only open during the context of the with statement. Indent
> the last line to match the assignment to r and you should be fine.
>
> Skip > ValueError: I/O operation on closed file
> >
> > Here is my code in a Python shell -
> >
> > >>> with open('x.csv','rb') as f:
> > ... r = csv.DictReader(f,delimiter=",")
> > >>> r.fieldnames
> The file is only open during the context of the with
> statement. Indent the last line to match the assignment to r and you
> should be fine.
> Skip
I have indented the line. I am working in the shell. The error is still
there.
Thanks.
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Re: CSV Error
On Sun, 28 Dec 2014 14:41:55 +0200, Jussi Piitulainen wrote:
> Skip Montanaro writes:
>
>> > ValueError: I/O operation on closed file
>> >
>> > Here is my code in a Python shell -
>> >
>> > >>> with open('x.csv','rb') as f:
>> > ... r = csv.DictReader(f,delimiter=",")
>> > >>> r.fieldnames
>>
>> The file is only open during the context of the with statement. Indent
>> the last line to match the assignment to r and you should be fine.
>
> Or, don't use "with" when experimenting in the shell.
>
>>>> import csv f = open('x.csv')
>>>> r = csv.DictReader(f, delimiter = ',')
>>>> r.fieldnames
>['Foo', 'Bar']
>>>>
Yes, Thanks. It's fixed.
Thanks.
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Re: CSV Error
Hmmm... Works for me.
% python
Python 2.7.6+ (2.7:db842f730432, May 9 2014, 23:53:26)
[GCC 4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.40)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> with open("coconutBattery.csv", "rb") as f:
... r = csv.DictReader(f)
... x = r.fieldnames
...
autoloading csv
>>> x
['date', 'capacity', 'loadcycles']
(Ignore the "autoloading" message. I use an autoloader in interactive
mode which comes in handy when I forget to import a module, as I did
here.)
It also works without assigning r.fieldnames to a new variable:
>>> with open("coconutBattery.csv", "rb") as f:
... r = csv.DictReader(f)
... r.fieldnames
...
['date', 'capacity', 'loadcycles']
>>> r.fieldnames
['date', 'capacity', 'loadcycles']
I think you're going to have to paste another example session to show
us what you might have done differently.
Skip
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Autoloader (was Re: CSV Error)
On Mon, Dec 29, 2014 at 12:58 AM, Skip Montanaro wrote: > (Ignore the "autoloading" message. I use an autoloader in interactive > mode which comes in handy when I forget to import a module, as I did > here.) We were discussing something along these lines a while ago, and I never saw anything truly satisfactory - there's no easy way to handle a missing name by returning a value (comparably to __getattr__), you have to catch it and then try to re-execute the failing code, which isn't perfect. How does yours work? Or was it one of the ones that was mentioned last time? ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Autoloader (was Re: CSV Error)
> We were discussing something along these lines a while ago, and I
> never saw anything truly satisfactory - there's no easy way to handle
> a missing name by returning a value (comparably to __getattr__), you
> have to catch it and then try to re-execute the failing code, which
> isn't perfect. How does yours work? Or was it one of the ones that was
> mentioned last time?
Just like that. I've attached a copy. As you said, I'm sure it's not
perfect, but it's handy in precisely those interactive interpreter
cases when *dope slap* you forgot to import a standard module before
launching into a block of code.
Skip
"""
autoload - load common symbols automatically on demand
When a NameError is raised attempt to find the name in a couple places.
Check to see if it's a name in a list of commonly used modules. If it's
found, import the name. If it's not in the common names try importing it.
In either case (assuming the imports succeed), reexecute the code in the
original context.
"""
import sys, traceback, re
_common = {}
# order important - most important needs to be last - os.path is chosen over
# sys.path for example
for mod in "sys os math xmlrpclib".split():
m = __import__(mod)
try:
names = m.__all__
except AttributeError:
names = dir(m)
names = [n for n in names if not n.startswith("_") and n.upper() != n]
for n in names:
_common[n] = mod
def _exec(import_stmt, tb):
f_locals = tb.tb_frame.f_locals
f_globals = tb.tb_frame.f_globals
sys.excepthook = _eh
try:
exec import_stmt in f_locals, f_globals
exec tb.tb_frame.f_code in f_locals, f_globals
finally:
sys.excepthook = _autoload_exc
def _autoload_exc(ty, va, tb):
##if ty != ImportError:
##traceback.print_exception(ty, va, tb)
##return
mat = re.search("name '([^']*)' is not defined", va.args[0])
if mat is not None:
name = mat.group(1)
if name in _common:
mod = _common[name]
print >> sys.stderr, "found", name, "in", mod, "module"
_exec("from %s import %s" % (mod, name), tb)
else:
print >> sys.stderr, "autoloading", name
_exec("import %s" % name, tb)
else:
traceback.print_exception(ty, va, tb)
_eh = sys.excepthook
sys.excepthook = _autoload_exc
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Re: Autoloader (was Re: CSV Error)
On Mon, Dec 29, 2014 at 1:15 AM, Skip Montanaro wrote: >> We were discussing something along these lines a while ago, and I >> never saw anything truly satisfactory - there's no easy way to handle >> a missing name by returning a value (comparably to __getattr__), you >> have to catch it and then try to re-execute the failing code, which >> isn't perfect. How does yours work? Or was it one of the ones that was >> mentioned last time? > > Just like that. I've attached a copy. As you said, I'm sure it's not > perfect, but it's handy in precisely those interactive interpreter > cases when *dope slap* you forgot to import a standard module before > launching into a block of code. Right, so its primary imperfection is that it potentially re-executes a block of code that had partially succeeded. Still of value, but definitely has its dangers. I wonder how hard it would be to tinker at the C level and add a __getattr__ style of hook... ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Re: Autoloader (was Re: CSV Error)
On Mon, Dec 29, 2014 at 1:22 AM, Chris Angelico wrote:
> I wonder how hard it would be to tinker at the C level and add a
> __getattr__ style of hook...
You know what, it's not that hard. It looks largeish as there are four
places where NameError (not counting UnboundLocalError, which I'm not
touching) can be raised - LOAD_GLOBAL and LOAD_NAME, both of which
have a fast path for the normal case and a fall-back for when
globals/builtins isn't a dict; but refactoring it into a helper
function keeps it looking reasonable.
Once that's coded in, all you need is:
def try_import(n):
try: return __import__(n)
except ImportError: raise NameError("Name %r is not defined"%n)
import sys
sys.__getglobal__ = try_import
and then any unknown name will be imported, if available, and
returned. It's just like __getattr__: if it returns something, it's as
if the name pointed to that thing, otherwise it raises NameError.
Is anyone else interested in the patch? Should I create a tracker
issue and upload it?
ChrisA
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Re: Autoloader (was Re: CSV Error)
On Mon, Dec 29, 2014 at 2:38 AM, Chris Angelico wrote:
> It's just like __getattr__: if it returns something, it's as
> if the name pointed to that thing, otherwise it raises NameError.
To clarify: The C-level patch has nothing about imports. What it does
is add a hook at the point where NameError is about to be raised,
allowing a Python function (stuffed into sys.__getglobal__) to control
what happens.
I do *not* recommend this for application code, and I would strongly
discourage it for library code, but it's handy for interactive work.
Like with Skip's hook, you could have a specific set of "from" imports
supported as well - here's a port of that script that uses this hook
instead:
"""
autoload - load common symbols automatically on demand
When a NameError is raised attempt to find the name in a couple places.
Check to see if it's a name in a list of commonly used modules. If it's
found, import the name. If it's not in the common names try importing it.
In either case (assuming the imports succeed), reexecute the code in the
original context.
"""
import sys
_common = {}
# order important - most important needs to be last - os.path is chosen over
# sys.path for example
for mod in "sys os math xmlrpclib".split():
m = __import__(mod)
try:
names = m.__all__
except AttributeError:
names = dir(m)
names = [n for n in names if not n.startswith("_") and n.upper() != n]
for n in names:
_common[n] = m
def _autoload_exc(name):
if name in _common:
return getattr(_common[name], name)
else:
return __import__(name)
sys.__getglobal__ = _autoload_exc
-- cut --
Note that I've removed the print-to-stderr when something gets
auto-imported. This is because the original hook inserted something
into the namespace, but this one doesn't; every time you reference
"exp", it'll look it up afresh from the math module, so it'd keep
spamming you with messages.
ChrisA
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Re: Autoloader (was Re: CSV Error)
On 28/12/2014 15:38, Chris Angelico wrote:
On Mon, Dec 29, 2014 at 1:22 AM, Chris Angelico wrote:
I wonder how hard it would be to tinker at the C level and add a
__getattr__ style of hook...
You know what, it's not that hard. It looks largeish as there are four
places where NameError (not counting UnboundLocalError, which I'm not
touching) can be raised - LOAD_GLOBAL and LOAD_NAME, both of which
have a fast path for the normal case and a fall-back for when
globals/builtins isn't a dict; but refactoring it into a helper
function keeps it looking reasonable.
Once that's coded in, all you need is:
def try_import(n):
try: return __import__(n)
except ImportError: raise NameError("Name %r is not defined"%n)
import sys
sys.__getglobal__ = try_import
and then any unknown name will be imported, if available, and
returned. It's just like __getattr__: if it returns something, it's as
if the name pointed to that thing, otherwise it raises NameError.
Is anyone else interested in the patch? Should I create a tracker
issue and upload it?
ChrisA
I'd raise a tracker issue so it's easier to find in the future.
--
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what you can do for our language.
Mark Lawrence
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Re: Autoloader (was Re: CSV Error)
On Mon, Dec 29, 2014 at 3:14 AM, Mark Lawrence wrote: >> Is anyone else interested in the patch? Should I create a tracker >> issue and upload it? > > I'd raise a tracker issue so it's easier to find in the future. http://bugs.python.org/issue23126 ChrisA -- https://mail.python.org/mailman/listinfo/python-list
Searching through more than one file.
I need to search through a directory of text files for a string.
Here is a short program I made in the past to search through a single
text file for a line of text.
How can I modify the code to search through a directory of files that
have different filenames, but the same extension?
fname = raw_input("Enter file name: ") #"*.txt"
fh = open(fname)
lst = list()
biglst=[]
for line in fh:
line=line.rstrip()
line=line.split()
biglst+=line
final=[]
for out in biglst:
if out not in final:
final.append(out)
final.sort()
print (final)
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Re: Searching through more than one file.
On 28/12/2014 17:27, Seymore4Head wrote:
I need to search through a directory of text files for a string.
Here is a short program I made in the past to search through a single
text file for a line of text.
How can I modify the code to search through a directory of files that
have different filenames, but the same extension?
fname = raw_input("Enter file name: ") #"*.txt"
fh = open(fname)
lst = list()
biglst=[]
for line in fh:
line=line.rstrip()
line=line.split()
biglst+=line
final=[]
for out in biglst:
if out not in final:
final.append(out)
final.sort()
print (final)
See the glob function in the glob module here
https://docs.python.org/3/library/glob.html#module-glob
Similar functionality is available in the pathlib module
https://docs.python.org/3/library/pathlib.html#module-pathlib but this
is only available with Python 3.4
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what you can do for our language.
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Re: Searching through more than one file.
Seymore4Head writes: > How can I modify the code to search through a directory of files that > have different filenames, but the same extension? Use the os.listdir function to read the directory. It gives you a list of filenames that you can filter for the extension you want. Per Mark Lawrence, there's also a glob function. -- https://mail.python.org/mailman/listinfo/python-list
Re: Searching through more than one file.
On 12/28/2014 12:27 PM, Seymore4Head wrote:
I need to search through a directory of text files for a string.
Here is a short program I made in the past to search through a single
text file for a line of text.
How can I modify the code to search through a directory of files that
have different filenames, but the same extension?
You have two other replies to your specific question, glob and
os.listdir. I would also mention the module fileinput:
https://docs.python.org/2/library/fileinput.html
import fileinput
from glob import glob
fnames = glob('*.txt')
for line in fileinput.input(fnames):
pass # do whatever
If you're not on Windows, I'd mention that the shell will expand the
wildcards for you, so you could get the filenames from argv even
simpler. See first example on the above web page.
I'm more concerned that you think the following code you supplied does a
search for a string. It does something entirely different, involving
making a crude dictionary. But it could be reduced to just a few lines,
and probably take much less memory, if this is really the code you're
working on.
fname = raw_input("Enter file name: ") #"*.txt"
fh = open(fname)
lst = list()
biglst=[]
for line in fh:
line=line.rstrip()
line=line.split()
biglst+=line
final=[]
for out in biglst:
if out not in final:
final.append(out)
final.sort()
print (final)
Something like the following:
import fileinput
from glob import glob
res = set()
fnames = glob('*.txt')
for line in fileinput.input(fnames):
res.update(line.rstrip().split())
print sorted(res)
--
DaveA
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Re: Searching through more than one file.
On 12/28/2014 02:12 PM, Dave Angel wrote:
On 12/28/2014 12:27 PM, Seymore4Head wrote:
I need to search through a directory of text files for a string.
Here is a short program I made in the past to search through a single
text file for a line of text.
How can I modify the code to search through a directory of files that
have different filenames, but the same extension?
You have two other replies to your specific question, glob and
os.listdir. I would also mention the module fileinput:
https://docs.python.org/2/library/fileinput.html
import fileinput
from glob import glob
fnames = glob('*.txt')
for line in fileinput.input(fnames):
pass # do whatever
If you're not on Windows, I'd mention that the shell will expand the
wildcards for you, so you could get the filenames from argv even
simpler. See first example on the above web page.
I'm more concerned that you think the following code you supplied does a
search for a string. It does something entirely different, involving
making a crude dictionary. But it could be reduced to just a few lines,
and probably take much less memory, if this is really the code you're
working on.
Note: the changes I suggest also should be tons faster, if you have
very many words you're parsing this way.
fname = raw_input("Enter file name: ") #"*.txt"
fh = open(fname)
lst = list()
biglst=[]
for line in fh:
line=line.rstrip()
line=line.split()
biglst+=line
final=[]
for out in biglst:
if out not in final:
final.append(out)
final.sort()
print (final)
Something like the following:
Untested, I should have said.
import fileinput
from glob import glob
res = set()
fnames = glob('*.txt')
for line in fileinput.input(fnames):
res.update(line.rstrip().split())
And I should have omitted the rsplit(), which does nothing that split()
isn't already going to do.
print sorted(res)
--
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Re: Searching through more than one file.
Dave Angel writes:
> res = set()
> fnames = glob('*.txt')
> for line in fileinput.input(fnames):
> res.update(line.rstrip().split())
> print sorted(res)
Untested:
print sorted(set(line.rstrip().split() for line in fileinput(fnames)))
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Re: Searching through more than one file.
On 12/28/2014 12:27 PM, Seymore4Head wrote: I need to search through a directory of text files for a string. Here is a short program I made in the past to search through a single text file for a line of text. How can I modify the code to search through a directory of files that have different filenames, but the same extension? You could simplify the relevant parts of idlelib/grep.py -- Terry Jan Reedy -- https://mail.python.org/mailman/listinfo/python-list
Re: suggestions for VIN parsing
On Fri, Dec 26, 2014 at 12:15 PM, Denis McMahon wrote: > Note, I think the 1981 model year ran KCA - DCA prefixes, not as shown on > the website you quoted. > Denis, Regarding the KCA - DCA prefixes, do you have a source as to why you think this? Here is what I have so far with a simple test at the end. I don't show is a dict which contains more information about the year/model, its not relivant. I am happy with how it is working, I hope to be able to decode BSA, and other British or more generally vintage motorcycle frame and engine numbers. BSA looks like a mess. def vin_to_year2(vin): vin = vin.lower() alpha_digit_alpha = re.match(r'^(\D+)(\d+)(\D+)$', vin) digit_alpha = re.match(r'^(\d+)(\D+)$', vin) alpha_digit = re.match(r'^(\D+)+(\d+)$', vin) alpha = re.match(r'^(\d+)$', vin) if alpha_digit_alpha: alpha_digit_alpha.groups() elif digit_alpha: g = digit_alpha.groups() if 100<=int(g[0]) and g[-1]=='n': # Triumph 1950: From 100N return 't1950' elif 101<=int(g[0])<=15808 and g[-1]=='na': # Triumph 1951: 101NA - 15808NA return 't1951' elif 15809<=int(g[0])<=25000 and g[-1]=='na': # Triumph 1952: 15809NA - 25000NA, see also alpha only vin for 1952 # Triumph 1952: 15809NA - 25000NA return 't1952' else: return None elif alpha_digit: g = alpha_digit.groups() if g[0] == 'h' and 101 <= int(g[1]) <= 760: # tu1957: H101 - H760 return 'tu1957' elif g[0] == 'h' and 761 <= int(g[1]) <= 5484:# tu1958: H761 - H5484 return 'tu1958' elif g[0] == 'h' and 5485 <= int(g[1]) <= 11511: # tu1959: H5485 - H11511 return 'tu1959' elif g[0] == 'h' and 11512 <= int(g[1]) <= 18611: # tu1960: H11512 - H18611 return 'tu1960' elif g[0] == 'h' and 18612 <= int(g[1]) <= 25251: # tu1961: H18612 - H25251 return 'tu1961' elif g[0] == 'h' and 25252 <= int(g[1]) <= 29732: # tu1962: H25252 - H29732 return 'tu1962' elif g[0] == 'h' and 29733 <= int(g[1]) <= 32464: # tu1963: H29733 - H32464 return 'tu1963' elif g[0] == 'h' and 32465 <= int(g[1]) <= 35986: # tu1964: H32465 - H35986 return 'tu1964' elif g[0] == 'h' and 35987 <= int(g[1]) <= 40527: # tu1965: H35987 - H40527 return 'tu1965' elif g[0] == 'h' and 40528 <= int(g[1]) <= 49832: # tu1966: H40528 - H49832 return 'tu1966' elif g[0] == 'h' and 49833 <= int(g[1]) <= 57082: # tu1967: H49833 - H57082 return 'tu1967' elif g[0] == 'h' and 57083 <= int(g[1]) <= 65572: # tu1968: H57083 - H65572 return 'tu1968' elif g[0] == 'h' and 65573 <= int(g[1]) <= 67331: # tu1969: H65573 - H67331 return 'tu1969' elif g[0] == 'd' and 101 <= int(g[1]) <= 7726: # tp1960: D101 - D7726 return 'tp1960' elif g[0] == 'd' and 7727 <= int(g[1]) <= 15788: # tp1961: D7727 - D15788 return 'tp1961' elif g[0] == 'd' and 15789 <= int(g[1]): # tp1962: D15789 - onward return 'tp1962' elif g[0] == 'du' and 101 <= int(g[1]) <= 5824: # 650 t65u1963: DU101 - DU5824 return 't65u1963' elif g[0] == 'du' and 5825 <= int(g[1]) <= 13374: # 650 t65u1964: DU5825 - DU13374 return 't65u1964' elif g[0] == 'du' and 5825 <= int(g[1]) <= 13374: # 650 t65u1965: DU5825 - DU13374 return 't65u1965' elif g[0] == 'du' and 24875 <= int(g[1]) <= 44393: # 650 t65u1966: DU24875 - DU44393 return 't65u1966' elif g[0] == 'du' and 44394 <= int(g[1]) <= 66245: # 650 t65u1967: DU44394 - DU66245 return 't65u1967' elif g[0] == 'du' and 66246 <= int(g[1]) <= 85903: # 650 t65u1968: DU66246 - DU85903 return 't65u1968' elif g[0] == 'du' and 85904 <= int(g[1]) <= 90282: # 650 t65u1969: DU85904 - DU90282 return 't65u1969' else: return None elif alpha: g = alpha.groups() if 25000 <= int(g[0]) <= 32302: # t1952: 25000 - 32302 return 't1952' elif 32303 <= int(g[0]) <= 44134: # t1953: 32303 - 44134 return 't1953' elif 44135 <= int(g[0]) <= 56699: # t1954: 44135 - 56699 return 't1954' elif 56700 <= int(g[0]) <= 70929: # t1955: 56700 - 70929 return 't1955' elif 70930 <= int(g[0]) <= 82799: # t1956: 70930 - 82799 return 't1956' elif 100 <= int(g[0]) <= 944 and g[0][0]=='0': # t1956: 0100 - 0944 return 't1956' elif g[0][0] == '0' and 945 <= int(g[0]) <= 5: # tp1957: 0945 - 05 return 'tp1957' elif g[0][0] == '0' and 6 <= int(g[0]) <= 20075: # tp1958: 06 - 020075 return 'tp1958' elif g[0][0] == '0' and 20076 <= int(g[0]) <= 29363: # tp1
Re: suggestions for VIN parsing
On Sunday, December 28, 2014 5:34:11 PM UTC-6, Vincent Davis wrote:
>
> [snip: code sample with Unicode spaces! Yes, *UNICODE SPACES*!]
Oh my! Might i offer some suggestions to improve the
readability of this code?
1. Indexing is syntactically noisy, so if you find yourself
fetching the same index more than once, then that is a good
time to store the indexed value into a local variable.
2. The only thing worse than duplicating code which fetches
the same index over and over again, is wrapping the fetch in
casting function (in this case: "int()") OVER and OVER again!
3. I see that you are utilizing regexps to aid in the logic,
and although i agree that regexps are overkill for this
problem (since it could "technically" be solved with string
methods) if *I* had to solve this problem, i would use the
power of regexps -- although i would use them more wisely ;-)
I have not studied the data thoroughly, but just by "grazing
over" the code you posted i can see a few distinct patterns
that emerge from the VIN data-set. Here is a description of
the patterns:
"\d+n"
"\d+na"
"d\d+"
"du\d+"
and the last pattern being all digits:
"\d+"
Even though your "verbose-run-on-conditional" would most
likely execute faster, i prefer to write code (when
performance is not mission critical!) in the most readable
and maintainable fashion. And in order to achieve that goal,
you always want to keep the main logic as succinct as
possible whist encapsulating the difficult bits in "suitably
abstracted structures".
DIVIDE AND CONQUER!
My approach would be as follows:
1. Create a map for each distinct set of VIN patterns with
the keys being a two-tuple that represents the low and high
limits of the serial number, and the values being the year
of that range..
database = {
'map_NA':{
(101, 15808): "Triumph 1951",
(15809, 25000): "Triumph 1952",
...,
},
'map_N':{
...,
},
'map_H':{
...,
},
'map_D':{
...,
},
'map_DU':{
...,
},
}
2. Create a regexp pattern for each "distinct VIN pattern".
The group captures will be used to strip-out *ONLY* the
numeric parts! Then concatenate all the regexp patterns into
a single monolithic program utilizing "named groups". (The
group names will be the corresponding "map_*" for which to
search)
[code stub here] :-P"
3. Now you can write some fairly simple logic.
prog = re.compile("pat1|pat2|pat3...")
def parse_vin(vin):
match = prog.search(vin)
if match:
gname = # Fetch the groupname from the match object.
number = # Fetch the digits from the group capture.
d = database[gname]
for k in d:
low, high = d[k]
if low <= number <= high:
return d[k]
return None
While this approach could be "heavy handed", i feel it will
be much easier to maintain and expand. I'd argue that if
you're going to utilize re's, then you should wield the full
power they provide, else, use some other method.
PS: You know you have a Unicode monkey on your back when you
use tools that insert Unicode spaces!
PPS: Hopefully i did not make any stupid mistakes, it's past my
bedtime!
--
https://mail.python.org/mailman/listinfo/python-list
Re: suggestions for VIN parsing
On Monday, December 29, 2014 12:50:39 AM UTC-6, Rick Johnson wrote:
[EDIT]
> 3. Now you can write some fairly simple logic.
>
> prog = re.compile("pat1|pat2|pat3...")
> def parse_vin(vin):
> match = prog.search(vin)
> if match:
> gname = # Fetch the groupname from the match object.
> number = # Fetch the digits from the group capture.
> d = database[gname]
> for k in d:
> low, high = d[k]
Dammit! That last line should have been:
low, high = k
But even better would be:
d = database[gname]
for low,high in d:
if low <= number <= high:
...
I knew something was tickling my sub-conscience as i sent
that reply, i should have known better!
PS: Hey, I said it was "fairly simple" logic, not "perfect"
logic!
--
https://mail.python.org/mailman/listinfo/python-list
Re: Searching through more than one file.
On Sunday, December 28, 2014 11:29:48 AM UTC-6, Seymore4Head wrote: > I need to search through a directory of text files for a string. > Here is a short program I made in the past to search through a single > text file for a line of text. Step1: Search through a single file. # Just a few more brush strokes... Step2: Search through all files in a directory. # Time to go exploring! Step3: Option to filter by file extension. # Waste not, want not! Step4: Option for recursing down sub-directories. # Look out deeply nested structures, here i come! # Look out deeply nested structures, here i come! # Look out deeply nested structures, here i come! # Look out deeply nested structures, here i come! # Look out deeply nested structures, here i come! # Look out deeply nested structures, here i come! # Look out deeply nested structures, here i come! [Opps, fell into a recursive black hole!] # Look out deeply nested structures, here i come! # Look out deeply nested structures, here i come! # Look out deeply nested structures, here i come! # Look out deeply nested structures, here i come! [BREAK] # Whew, no worries, MaximumRecursionError is my best friend! ;-) In addition to the other advice, you might want to check out os.walk(). -- https://mail.python.org/mailman/listinfo/python-list
