I'm sure that the answer for this is out there, but I've read the site info, I've watched the video they made and I've tried to find a really basic tutorial but I can't. I've been messing about with this for most of the day and It's not really making sense to me.
Here's my error:
vco#geoHP:~$ python3 a_blah.py "don't scare the cats" magic
Traceback (most recent call last):
File "a_blah.py", line 20, in <module>
arguments = docopt.docopt(__doc__)
File "/usr/lib/python3/dist-packages/docopt.py", line 579, in docopt
raise DocoptExit()
docopt.DocoptExit: Usage:
a_blah.py <start>... <end>
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "a_blah.py", line 33, in <module>
except DocoptExit:
NameError: name 'DocoptExit' is not defined
line 20 - I don't see why that line is creating an error, it worked before and I've seen that exact line in others programmes?
I don't know why the line 570 of docopt is creating an error - I've seen others use DocoptExit(), isn't this something that's just part of Docopt? Do I have to write my own exit function for this? (I've not seen anyone else do that)
here's the code
import docopt
if __name__ == '__main__':
try:
arguments = docopt.docopt(__doc__)
print(arguments['<start>'])
print("that was that")
print(arguments['<end>'])
except docopt.DocoptExit:
print("this hasn't worked")
What I'm trying to make this for is a script that I've written that moves files from one place to another based on their extension.
So the arguments at the command line will be file type, start directory, destination directory, and an option to delete them from the start directory after they've been moved.
I'm trying (and failing) to get docopt working on it's own prior to including it in the other script though.
The exception you want is in docopt's namespace. You never import it into your global namespace, so you can't refer to it simply with it's name. You need to import it separately or refer to it through the module. You also shouldn't use parenthesis after the exception.
import docopt
try:
# stuff
except docopt.DocoptExit:
# other stuff
or
import docopt
from docopt import DocoptExit
try:
# stuff
except DocoptExit:
# other stuff
Related
I recently made a program using an external document with pickle. But when it tries to load the file with pickle, I got this error (the file is already existing but it also fails when the file in't existing):
python3.6 check-graph_amazon.py
a
b
g
URL to follow www.amazon.com
Product to follow Pool_table
h
i
[' www.amazon.com', ' Pool_table', []]
p
Traceback (most recent call last):
File "check-graph_amazon.py", line 17, in <module>
tab_simple = pickle.load(doc_simple)
io.UnsupportedOperation: read
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "check-graph_amazon.py", line 42, in <module>
pickle.dump(tab_simple, 'simple_data.dat')
TypeError: file must have a 'write' attribute
Here is the code :
import pickle5 as pickle
#import os
try:
print("a")
with open('simple_data.dat', 'rb') as doc_simple:
print("b")
tab_simple = pickle.load(doc_simple)
print("c")
print(tab_simple)
print("d")
URL = tab_simple[0]
produit_nom = tab_simple[1]
tous_jours = tab_simple[2]
print("f")
except :
print("g")
URL = str(input("URL to follow"))
produit_nom = str(input("Product to follow"))
with open('simple_data.dat', 'wb+') as doc_simple:
print("h")
#os.system('chmod +x simple_data.dat')
tab_simple = []
tab_simple.append(URL)
tab_simple.append(produit_nom)
tab_simple.append([])
print(tab_simple)
print("c'est le 2")
print("p")
pickle.dump(tab_simple, 'simple_data.dat')
print("q")
The prints are here to show which lines are executed. The os.system is here to allow writing on the file but the error is persisting.
I don't understand why it's said that the document doesn't have a write attribute because I opened it in writing mode. And I neither understand the first error where it can't load the file.
If it can help you the goal of this script is to initialise the program, with a try. It tries to open the document in reading mode in the try part and then set variables. If the document doesn't exist (because the program is lauched for the first time) it goes in the except part and create the document, before writing informations on it.
I hope you will have any clue, including changing the architecture of the code if you have a better way to make an initialisation for the 1st time the program is launched.
Thanks you in advance and sorry if the code isn't well formated, I'm a beginner with this website.
Quote from the docs for pickle.dump:
pickle.dumps(obj, protocol=None, *, fix_imports=True)
Write a pickled representation of obj to the open file object file. ...
...
The file argument must have a write() method that accepts a single bytes argument. It can thus be an on-disk file opened for binary writing, an io.BytesIO instance, or any other custom object that meets this interface.
So, you should pass to this function a file object, not a file name, like this:
with open("simple_data.dat", "wb"): as File:
pickle.dump(tab_simple, File)
Yeah, in your case the file has already been opened, so you should write to doc_simple.
I can't seem to generate this exception with python code with a genuine error.
I used the code from this question to check my work. Here it is, modified only slightly:
import py_compile
def check(python_file):
try:
file = open(python_file, 'r')
py_compile.compile(python_file, doraise=True)
except py_compile.PyCompileError:
print("<"+python_file+"> does not contain syntactically correct Python code")
else:
print("Compiled " + python_file + " with no issues.")
check("example.py")
The file example.py contains just:
print ("This is fine.")
prant ("This should be an error.")
'prant' instead of 'print' would be a simple syntax error, and if I run 'python example.py' then I see:
This is fine.
Traceback (most recent call last):
File "example.py", line 2, in <module>
prant ("This should be an error.")
NameError: name 'prant' is not defined
If I call the script at the top 'compiler.py' and then run 'python compiler.py' it will say there are no issues.
I have verified that compiler.py will complain about syntactic correctness if there are unmatched parentheses or quotes, so it does catch some problems. But I would like to be able to detect when a file has errors in the same way that running 'python example.py' or whatever would do. Basically, if it has an error when running it with 'python', I'd like to be able to detect that.
Is there a way to do this? And why is PyCompileError not being thrown when there is a syntax error?
I've created a standalone exe Windows service written in Python and built with pyInstaller. When I try to import wmi, an exception is thrown.
What's really baffling is that I can do it without a problem if running the code in a foreground exe, or a foreground python script, or a python script running as a background service via pythonservice.exe!
Why does it fail under this special circumstance of running as a service exe?
import wmi
Produces this error for me:
com_error: (-2147221020, 'Invalid syntax', None, None)
Here's the traceback:
Traceback (most recent call last):
File "<string>", line 43, in onRequest
File "C:\XXX\XXX\XXX.pyz", line 98, in XXX
File "C:\XXX\XXX\XXX.pyz", line 31, in XXX
File "C:\XXX\XXX\XXX.pyz", line 24, in XXX
File "C:\XXX\XXX\XXX.pyz", line 34, in XXX
File "C:\Program Files (x86)\PyInstaller-2.1\PyInstaller\loader\pyi_importers.py", line 270, in load_module
File "C:\XXX\XXX\out00-PYZ.pyz\wmi", line 157, in <module>
File "C:\XXX\XXX\out00-PYZ.pyz\win32com.client", line 72, in GetObject
File "C:\XXX\XXX\out00-PYZ.pyz\win32com.client", line 87, in Moniker
wmi.py line 157 has a global call to GetObject:
obj = GetObject ("winmgmts:")
win32com\client__init.py__ contains GetObject(), which ends up calling Moniker():
def GetObject(Pathname = None, Class = None, clsctx = None):
"""
Mimic VB's GetObject() function.
ob = GetObject(Class = "ProgID") or GetObject(Class = clsid) will
connect to an already running instance of the COM object.
ob = GetObject(r"c:\blah\blah\foo.xls") (aka the COM moniker syntax)
will return a ready to use Python wrapping of the required COM object.
Note: You must specifiy one or the other of these arguments. I know
this isn't pretty, but it is what VB does. Blech. If you don't
I'll throw ValueError at you. :)
This will most likely throw pythoncom.com_error if anything fails.
"""
if clsctx is None:
clsctx = pythoncom.CLSCTX_ALL
if (Pathname is None and Class is None) or \
(Pathname is not None and Class is not None):
raise ValueError("You must specify a value for Pathname or Class, but not both.")
if Class is not None:
return GetActiveObject(Class, clsctx)
else:
return Moniker(Pathname, clsctx)
The first line in Moniker(), i.e. MkParseDisplayName() is where the exception is encountered:
def Moniker(Pathname, clsctx = pythoncom.CLSCTX_ALL):
"""
Python friendly version of GetObject's moniker functionality.
"""
moniker, i, bindCtx = pythoncom.MkParseDisplayName(Pathname)
dispatch = moniker.BindToObject(bindCtx, None, pythoncom.IID_IDispatch)
return __WrapDispatch(dispatch, Pathname, clsctx=clsctx)
Note: I tried using
pythoncom.CoInitialize()
which apparently solves this import problem within a thread, but that didn't work...
I also face the same issue and I figure out this issue finally,
import pythoncom and CoInitialize pythoncom.CoInitialize (). They import wmi
import pythoncom
pythoncom.CoInitialize ()
import wmi
I tried solving this countless ways. In the end, I threw in the towel and had to just find a different means of achieving the same goals I had with wmi.
Apparently that invalid syntax error is thrown when trying to create an object with an invalid "moniker name", which can simply mean the service, application, etc. doesn't exist on the system. Under this circumstance "winmgmts" just can't be found at all it seems! And yes, I tried numerous variations on that moniker with additional specs, and I tried running the service under a different user account, etc.
Honestly I didn't dig in order to understand why this occurs.
Anyway, the below imports solved my problem - which was occurring only when ran from a Flask instance:
import os
import pythoncom
pythoncom.CoInitialize()
from win32com.client import GetObject
import wmi
The error "com_error: (-2147221020, 'Invalid syntax', None, None)" is exactly what popped up in my case so I came here after a long time of searching the web and voila:
Under this circumstance "winmgmts" just can't be found at all it
seems!
This was the correct hint for because i had just a typo , used "winmgmt:" without trailing 's'. So invalid sythax refers to the first methods parameter, not the python code itself. o_0 Unfortunately I can't find any reference which objects we can get with win32com.client.GetObject()... So if anybody has a hint to which params are "allowed" / should work, please port it here. :-)
kind regards
ChrisPHL
I would like to know if there is a way to directly run a python function directly from a file by just mentioning the filename followed by the function in a single line.
For example, lets say I have a file 'test.py' with a function 'newfunction()'.
----------test.py-----------
def newfunction():
print 'welcome'
Can I run the newfunction() doing something similar to this.
python test.py newfunction
I know how to import and to call functions etc.Having seen similar commands in django etc (python manage.py runserver), I felt there is a way to directly call a function like this. Let me know if something similar is possible.
I want to be able to use it with django. But an answer that is applicable everywhere would be great.
Try with globals() and arguments (sys.argv):
#coding:utf-8
import sys
def moo():
print 'yewww! printing from "moo" function'
def foo():
print 'yeeey! printing from "foo" function'
try:
function = sys.argv[1]
globals()[function]()
except IndexError:
raise Exception("Please provide function name")
except KeyError:
raise Exception("Function {} hasn't been found".format(function))
Results:
➜ python calling.py foo
yeeey! printing from "foo" function
➜ python calling.py moo
yewww! printing from "moo" function
➜ python calling.py something_else
Traceback (most recent call last):
File "calling.py", line 18, in <module>
raise Exception("Function {} hasn't been found".format(function))
Exception: Function something_else hasn't been found
➜ python calling.py
Traceback (most recent call last):
File "calling.py", line 16, in <module>
raise Exception("Please provide function name")
Exception: Please provide function name
I think you should take a look at:
https://docs.djangoproject.com/en/1.9/howto/custom-management-commands/
All those commands like migrate, runserver or dbshell etc. are implemented like how it was described in that link:
Applications can register their own actions with manage.py. To do this, just add a management/commands directory to the application.
Django will register a manage.py command for each Python module in that directory whose name doesn’t begin with an underscore.
I am trying to write a python program that will eventually take a command line argument of a file, determine if its a tar or zip etc file and then exctract it accordingly. I am just trying to get the tar part working now and I am getting multiple errors. The file I am checking for resides in my ~/ directory. Any ideas would be great.
#!/usr/bin/python
import tarfile
import os
def open_tar(file):
if tarfile.is_tarfile(file):
try:
tar = tarfile.open("file")
tar.extractall()
tar.close()
except ReadError:
print "File is somehow invalid or can not be handled by tarfile"
except CompressionError:
print "Compression method is not supported or data cannot be decoded"
except StreamError:
print "Is raised for the limitations that are typical for stream-like TarFile objects."
except ExtractError:
print "Is raised for non-fatal errors when using TarFile.extract(), but only if TarFile.errorlevel== 2."
if __name__ == '__main__':
file = "xampp-linux-1.7.3a.tar.gz"
print os.getcwd()
print file
open_tar(file)
Here are the errors. IF I comment out the Read Error, I just get teh same error on the next exception as well.
tux#crosnet:~$ python openall.py
/home/tux
xampp-linux-1.7.3a.tar.gz
Traceback (most recent call last):
File "openall.py", line 25, in <module>
open_tar(file)
File "openall.py", line 12, in open_tar
except ReadError:
NameError: global name 'ReadError' is not defined
tux#crosnet:~$
You can clearly see in your error it states
NameError: global name 'ReadError' is not defined
ReadError is not a global python name. If you look at the tarfile documentation you will see ReadError is part of that modules exceptions. So in this case, you would want to do:
except tarfile.ReadError:
# rest of your code
And you will need to do the same for the rest of those errors. Also, if all those errors will generate the same result (an error message of some sort, or a pass) you can simply do:
except (tarfile.ReadError, tarfile.StreamError) # and so on
Instead of doing them each on a seperate line. That's only if they will give the same exception
You would need to use except tarfile.ReadError or alternatively use from tarfile import is_tarfile, open, ReadError, CompressionError, etc. and put that inside the open_tar function instead of globally.
I think you might need tarfile.ReadError rather than just ReadError?
Okay. All your exceptions (ReadError, CompressionError etc.) are inside the tarfile module and so you'll have to say except tarfile.ReadError instead of just except ReadError.