I am trying to run a python script through another python script, with subprocess.Popen. I have:
import subprocess
p = subprocess.Popen(['/Library/Frameworks/Python.framework/Versions/3.8/bin/python3',
'myscript.py'])
p.poll() is None
Sometimes I get:
Out[21]: <subprocess.Popen at 0x11b5823a0>
But nothing happens and the script is not executed.
Some other times I get the following error:
Traceback (most recent call last):
File "myscript.py", line 11, in <module>
import requests
ModuleNotFoundError: No module named 'requests'
I am pretty sure that the requests module have been properly imported in the script I am trying to run. Any help welcome ;)
Related
help(time.sleep)
Traceback (most recent call last): File "", line 1, in
NameError: name 'time' is not defined
At the beginning of the program you have to import all the modules you need. To do this you need to use the import keyword followed by the package name.
import time
help(time.sleep)
I have a script named requests.py that needs to use the third-party requests package. The script either can't import the package, or can't access its functionality.
Why isn't this working, and how do I fix it?
Trying a plain import and then using the functionality results in an AttributeError:
import requests
res = requests.get('http://www.google.ca')
print(res)
Traceback (most recent call last):
File "/Users/me/dev/rough/requests.py", line 1, in <module>
import requests
File "/Users/me/dev/rough/requests.py", line 3, in <module>
requests.get('http://www.google.ca')
AttributeError: module 'requests' has no attribute 'get'
In more recent versions of Python, the error message instead reads AttributeError: partially initialized module 'requests' has no attribute 'get' (most likely due to a circular import).
Using from-import of a specific name results in an ImportError:
from requests import get
res = get('http://www.google.ca')
print(res)
Traceback (most recent call last):
File "requests.py", line 1, in <module>
from requests import get
File "/Users/me/dev/rough/requests.py", line 1, in <module>
from requests import get
ImportError: cannot import name 'get'
In more recent versions of Python, the error message instead reads ImportError: cannot import name 'get' from partially initialized module 'requests' (most likely due to a circular import) (/Users/me/dev/rough/requests.py).
Using from-import for a module inside the package results in a different ImportError:
from requests.auth import AuthBase
Traceback (most recent call last):
File "requests.py", line 1, in <module>
from requests.auth import AuthBase
File "/Users/me/dev/rough/requests.py", line 1, in <module>
from requests.auth import AuthBase
ImportError: No module named 'requests.auth'; 'requests' is not a package
Using a star-import and then using the functionality raises a NameError:
from requests import *
res = get('http://www.google.ca')
print(res)
Traceback (most recent call last):
File "requests.py", line 1, in <module>
from requests import *
File "/Users/me/dev/rough/requests.py", line 3, in <module>
res = get('http://www.google.ca')
NameError: name 'get' is not defined
This happens because your local module named requests.py shadows the installed requests module you are trying to use. The current directory is prepended to sys.path, so the local name takes precedence over the installed name.
An extra debugging tip when this comes up is to look at the Traceback carefully, and realize that the name of your script in question is matching the module you are trying to import:
Notice the name you used in your script:
File "/Users/me/dev/rough/requests.py", line 1, in <module>
The module you are trying to import: requests
Rename your module to something else to avoid the name collision.
Python may generate a requests.pyc file next to your requests.py file (in the __pycache__ directory in Python 3). Remove that as well after your rename, as the interpreter will still reference that file, re-producing the error. However, the pyc file in __pycache__ should not affect your code if the py file has been removed.
In the example, renaming the file to my_requests.py, removing requests.pyc, and running again successfully prints <Response [200]>.
The error occurs because a user-created script has a name-clash with a library filename. Note, however, that the problem can be caused indirectly. It might take a little detective work to figure out which file is causing the problem.
For example: suppose that you have a script mydecimal.py that includes import decimal, intending to use the standard library decimal library for accurate floating-point calculations with decimal numbers. That doesn't cause a problem, because there is no standard library mydecimal. However, it so happens that decimal imports numbers (another standard library module) for internal use, so a script called numbers.py in your project would cause the problem.
In one especially pernicious case, having a file named token.py in a project (or the current working directory, when starting up Python in interactive mode) causes the interactive help to break:
$ touch token.py
$ python
Python 3.8.10 (default, Nov 14 2022, 12:59:47)
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> help
Type help() for interactive help, or help(object) for help about object.
>>> help()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python3.8/_sitebuiltins.py", line 102, in __call__
import pydoc
File "/usr/lib/python3.8/pydoc.py", line 66, in <module>
import inspect
File "/usr/lib/python3.8/inspect.py", line 40, in <module>
import linecache
File "/usr/lib/python3.8/linecache.py", line 11, in <module>
import tokenize
File "/usr/lib/python3.8/tokenize.py", line 35, in <module>
from token import EXACT_TOKEN_TYPES
ImportError: cannot import name 'EXACT_TOKEN_TYPES' from 'token' (/current/working/directory/token.py)
The traceback tells us all we need to know: calling help triggers a deferred import of the standard library pydoc, which indirectly attempts to import the standard library token, but finds our token.py which doesn't contain the appropriate name. In older versions of Python, it was even worse: tokenize would do a star-import from token, and then its top-level code would try to use a name defined there, resulting in NameError - and a stack trace not mentioning the file name token.py.
If you still encounter problems like this after tracking own and renaming or removing the appropriate .py files in your project, also check for .pyc files that Python uses to cache bytecode compilation when importing modules. In 3.x, these will be stored in folders with the special name __pycache__; it is safe to delete such folders and files, and possible to suppress them (but you normally won't want to).
I am trying to create a GUI that I can all it from the terminal (Ubuntu here). The problem is, whenever I try to run the code from the terminal, I get the following message:
Traceback (most recent call last):
File "alert.pyw", line 3, in <module>
from PyQt5.QtCore import *
ImportError: No module named 'PyQt5'
The problem is: I only get this message when I try to call the program from the terminal using
python3 alert.pyw Hello
PyQt5 is installed and when I import it from the shell it (apparently) works fine...
I have a script named requests.py that needs to use the third-party requests package. The script either can't import the package, or can't access its functionality.
Why isn't this working, and how do I fix it?
Trying a plain import and then using the functionality results in an AttributeError:
import requests
res = requests.get('http://www.google.ca')
print(res)
Traceback (most recent call last):
File "/Users/me/dev/rough/requests.py", line 1, in <module>
import requests
File "/Users/me/dev/rough/requests.py", line 3, in <module>
requests.get('http://www.google.ca')
AttributeError: module 'requests' has no attribute 'get'
In more recent versions of Python, the error message instead reads AttributeError: partially initialized module 'requests' has no attribute 'get' (most likely due to a circular import).
Using from-import of a specific name results in an ImportError:
from requests import get
res = get('http://www.google.ca')
print(res)
Traceback (most recent call last):
File "requests.py", line 1, in <module>
from requests import get
File "/Users/me/dev/rough/requests.py", line 1, in <module>
from requests import get
ImportError: cannot import name 'get'
In more recent versions of Python, the error message instead reads ImportError: cannot import name 'get' from partially initialized module 'requests' (most likely due to a circular import) (/Users/me/dev/rough/requests.py).
Using from-import for a module inside the package results in a different ImportError:
from requests.auth import AuthBase
Traceback (most recent call last):
File "requests.py", line 1, in <module>
from requests.auth import AuthBase
File "/Users/me/dev/rough/requests.py", line 1, in <module>
from requests.auth import AuthBase
ImportError: No module named 'requests.auth'; 'requests' is not a package
Using a star-import and then using the functionality raises a NameError:
from requests import *
res = get('http://www.google.ca')
print(res)
Traceback (most recent call last):
File "requests.py", line 1, in <module>
from requests import *
File "/Users/me/dev/rough/requests.py", line 3, in <module>
res = get('http://www.google.ca')
NameError: name 'get' is not defined
This happens because your local module named requests.py shadows the installed requests module you are trying to use. The current directory is prepended to sys.path, so the local name takes precedence over the installed name.
An extra debugging tip when this comes up is to look at the Traceback carefully, and realize that the name of your script in question is matching the module you are trying to import:
Notice the name you used in your script:
File "/Users/me/dev/rough/requests.py", line 1, in <module>
The module you are trying to import: requests
Rename your module to something else to avoid the name collision.
Python may generate a requests.pyc file next to your requests.py file (in the __pycache__ directory in Python 3). Remove that as well after your rename, as the interpreter will still reference that file, re-producing the error. However, the pyc file in __pycache__ should not affect your code if the py file has been removed.
In the example, renaming the file to my_requests.py, removing requests.pyc, and running again successfully prints <Response [200]>.
The error occurs because a user-created script has a name-clash with a library filename. Note, however, that the problem can be caused indirectly. It might take a little detective work to figure out which file is causing the problem.
For example: suppose that you have a script mydecimal.py that includes import decimal, intending to use the standard library decimal library for accurate floating-point calculations with decimal numbers. That doesn't cause a problem, because there is no standard library mydecimal. However, it so happens that decimal imports numbers (another standard library module) for internal use, so a script called numbers.py in your project would cause the problem.
In one especially pernicious case, having a file named token.py in a project (or the current working directory, when starting up Python in interactive mode) causes the interactive help to break:
$ touch token.py
$ python
Python 3.8.10 (default, Nov 14 2022, 12:59:47)
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> help
Type help() for interactive help, or help(object) for help about object.
>>> help()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python3.8/_sitebuiltins.py", line 102, in __call__
import pydoc
File "/usr/lib/python3.8/pydoc.py", line 66, in <module>
import inspect
File "/usr/lib/python3.8/inspect.py", line 40, in <module>
import linecache
File "/usr/lib/python3.8/linecache.py", line 11, in <module>
import tokenize
File "/usr/lib/python3.8/tokenize.py", line 35, in <module>
from token import EXACT_TOKEN_TYPES
ImportError: cannot import name 'EXACT_TOKEN_TYPES' from 'token' (/current/working/directory/token.py)
The traceback tells us all we need to know: calling help triggers a deferred import of the standard library pydoc, which indirectly attempts to import the standard library token, but finds our token.py which doesn't contain the appropriate name. In older versions of Python, it was even worse: tokenize would do a star-import from token, and then its top-level code would try to use a name defined there, resulting in NameError - and a stack trace not mentioning the file name token.py.
If you still encounter problems like this after tracking own and renaming or removing the appropriate .py files in your project, also check for .pyc files that Python uses to cache bytecode compilation when importing modules. In 3.x, these will be stored in folders with the special name __pycache__; it is safe to delete such folders and files, and possible to suppress them (but you normally won't want to).
Am new to python, i installed python 3.2 in my windows and tried the following code,
import urllib, urllister
usock = urllib.urlopen("http://diveintopython.net/")
parser = urllister.URLLister()
parser.feed(usock.read())
usock.close()
parser.close()
for url in parser.urls: print(url)
Its showing,
Traceback (most recent call last):
File "demo.py", line 1, in <module>
import urllib, urllister
ImportError: No module named urllister
How to add that module?
urllister is not part of the standard library.
You must download file urllister.py from here, and save it next to the script you're running.