This question may be obvious but I have trouble figuring out what's going on. As far as I can see there are no similar problems addressed on the internet.
I'm using Python 3.7 and Spyder (hence the Anaconda bundle). The problem I have is that I'm not able to use SymPy. I've written the following test code which seems to be correct according to documentation and examples:
from sympy import *
x, y, z, t = symbols('x y z t')
expr = x**2+2
d = diff(expr,x)
print(d)
When compiling this I get the message
NameError: name 'symbols' is not defined
What's going on here?
try the following:
import sympy as sp
x, y, z, t = sp.symbols('x, y, z, t')
expr = x**2+2
d = diff(expr,x)
print(d)
The issue MIGHT be, that you called your source file 'sympy.py'.
If you then "import sympy", you actually import your own source file instead of the sympy library. The solution is then to just rename your source file to something else... like "test.py" and try to run it.
The following comment actually gave ne the hint. However, since it's not the original poster, he might have had a different issue.
"Interestingly I have this problem when running the script as a file but not when running the code inside the console line by line. – logicbloke Jul 26 '20 at 1:00"
Your code works fine when I try it.
Have you updated your software recently?
If you're on Ubuntu, try running an update via the command line:
sudo apt-get update
For more information on this, check: https://askubuntu.com/questions/222348/what-does-sudo-apt-get-update-do
Related
Using interactive Glue Sessions in a Jupyter Notebook was working correctly with the aws-glue-sessions package version 0.32 installed. After upgrading with pip3 install --upgrade jupyter boto3 aws-glue-sessions to version 0.35, the kernel would not start. Gave an error message in GlueKernel.py line 443 in set_glue_version Exception: Valid Glue versions are {'3.0', '2,0} and the Kernel won't start.
Reverting to version 0.32 resolves the issue. Tried installing 0.35, 0.34, 0.33 and get the error, which makes me think it's something I'm doing wrong or don't understand and not something in the product. Is there anything additional I need to do to upgrade the version of the aws-glue-sessions?
Obviously this is not a good workaround - but it worked for me.
I went into the file GlueKernel.py in the directory: \site-packages\aws_glue_interactive_sessions_kernel\glue_pyspark
and hard-coded the 2nd line of this function to set the version to "3.0"
I'm on windows
def set_glue_version(self, glue_version):
glue_version = str("3.0")
if glue_version not in VALID_GLUE_VERSIONS:
raise Exception(f"Valid Glue versions are {VALID_GLUE_VERSIONS}")
self.glue_version = glue_version
I am a bit lost here as well -- and confused. I will add that I am a python newbie. I am running the whole thing on Windows. AWS has an article that describes the installation. So, I am assuming it's supported. I get the same error as #theOtherOne.
line 443 in set_glue_version Exception: Valid Glue versions are {'3.0', '2,0}
I checked GlueKernel.py of glue_pyspark, and found this code:
def _retrieve_os_env_variable(self, key):
_, output = subprocess.getstatusoutput(f"echo ${key}")
return output or os.environ.get(key)
When I run the code below manually, I get $GLUE_VERSION as final result. That obviously doesn't match '2.0' or '3.0'. The command for retrieving environment variables on Windows is a different one. If my understanding is correct, then this whole thing will never work on Windows. Maybe I am the only one who wants to run it on Windows and no one else cares? I got it to work on WSL, but still. I lost quite some time to fix something that cannot be fixed (or can it?)
import subprocess
import os
_, output = subprocess.getstatusoutput(f"echo $GLUE_VERSION")
osoutput = os.environ.get("GLUE_VERSION")
print(output) #$GLUE_VERSION
print (osoutput) #'3.0'
print(output or osoutput) #$GLUE_VERSION
enter image description here
So the issue seems to be that GLUE_VERSION is not set in the environment variables. Once this is set - it works
I am working with a command line tool called 'ideviceinfo' (see https://github.com/libimobiledevice) to help me to quickly get back serial, IMEI and battery health information from the iOS device I work with daily. It executes much quicker than Apple's own 'cfgutil' tools.
Up to know I have been able to develop a more complicated script than the one shown below in PyCharm (my main IDE) to assign specific values etc to individual variables and then to use something like to pyclip and pyautogui to help automatically paste these into the fields of the database app we work with. I have also been able to use the simplified version of the script both in Mac OS X terminal and in the python shell without any hiccups.
I am looking to use AppleScript to help make running the script as easy as possible.
When I try to use Applescript's "do shell script 'python script.py'" I just get back a string of lenght zero when I call 'ideviceinfo'. The exact same thing happens when I try to build an Automator app with a 'Run Shell Script' component for "python script.py".
I have tried my best to isolate the problem down. When other more basic commands such as 'date' are called within the script they return valid strings.
#!/usr/bin/python
import os
ideviceinfoOutput = os.popen('ideviceinfo').read()
print ideviceinfoOutput
print len (ideviceinfoOutput)
boringExample = os.popen('date').read()
print boringExample
print len (boringExample)
I am running Mac OS X 10.11 and am on Python 2.7
Thanks.
I think I've managed to fix it on my own. I just need to be far more explicit about where the 'ideviceinfo' binary (I hope that's the correct term) was stored on the computer.
Changed one line of code to
ideviceinfoOutput = os.popen('/usr/local/bin/ideviceinfo').read()
and all seems to be OK again.
I'm trying to debug some code in a Jupyter notebook. I've tried 3 4 different methods, and they all suffer from the same problem:
--Return--
None
> <ipython-input-22-04c6f5c205d1>(3)<module>()
1 import IPython.core.debugger as dbg
2 dber = dbg.Tracer()
----> 3 dber()
4 tst = huh.plot(ret_params=True)
5 type(tst)
ipdb> n
> y:\miniconda\lib\site-packages\ipython\core\interactiveshell.py(2884)run_code()
2882 finally:
2883 # Reset our crash handler in place
-> 2884 sys.excepthook = old_excepthook
2885 except SystemExit as e:
2886 if result is not None:
as you can see, the n command, which from what I understood from the pdb documentation should execute the next line (I'm assuming ipdb is just pdb adapted to work on IPython, especially since I can't find any command documentation that refers specifically to ipdb and not pdb)
s also has the same problem. This is actually what I want to do - step into the plot call (from what I understand, this is what s is supposed to do), but what I get is exactly the same as what I get from n. I also just tried r and I get the same problem.
Every example I've seen just uses Tracer()() or IPython.core.debugger.PDB().set_trace() to set a breakpoint in the line that follows the command, but both cause the same problems (and, I assume, are actually the exact same thing).
I also tried %debug (MultipleInstanceError) and %%debug (Doesn't show the code in the line being executed - just says what line, using s doesn't step into the function, just runs the line).
Edit: turns out, according to a blog post from April of this year, plain pdb should also work. It does allow me to interactively debug the notebook, but it only prints the current line being debugged (probably not a bug), and it has the same problem as IPython's set_trace() and Tracer()()
on plain IPython console, IPython's set_trace (only one I've tested) works just fine.
I encountered the same problem when debugging in Jupyter Notebook. What is working for me however, is when I call set_trace() inside a function. Why is explained here (click), though I don't really understand why others don't encounter this problem. Anyway, if you need a pragmatic solution for your problem and you want to debug a self-written function, try this:
from IPython.core.debugger import set_trace
def thisfunction(x):
set_trace() # start debugging when calling the function
x += 2
return x
thisfunction(5) # ipdb console opens and I can use 'n'
Now I can use 'n' and the debugging process runs the next line without problems. If I use the following code, however, I run into your above mentioned problem.
from IPython.core.debugger import set_trace
def thisfunction(x):
x += 2
return x
set_trace() # start debugging before calling the function.
# Calling 's' in the ipdb console to step inside "thisfunction" produces an error
thisfunction(5)
Hope this helps until somebody could solve the problem completely.
cv2.imread is always returning NoneType.
I am using python version 2.7 and OpenCV 2.4.6 on 64 bit Windows 7.
Maybe it's some kind of bug or permissions issue because the exact same installation of python and cv2 packages in another computer works correctly. Here's the code:
im = cv2.imread("D:\testdata\some.tif",CV_LOAD_IMAGE_COLOR)
I downloaded OpenCV from http://www.lfd.uci.edu/~gohlke/pythonlibs/#opencv. Any clue would be appreciated.
First, make sure the path is valid, not containing any single backslashes. Check the other answers, e.g. https://stackoverflow.com/a/26954461/463796.
If the path is fixed but the image is still not loading, it might indeed be an OpenCV bug that is not resolved yet, as of 2013. cv2.imread is not working properly under Win32 for me either.
In the meantime, use LoadImage, which should work fine.
im = cv2.cv.LoadImage("D:/testdata/some.tif", CV_LOAD_IMAGE_COLOR)
In my case the problem was the spaces in the path. After I moved the images to a path with no spaces it worked.
Try changing the direction of the slashes
im = cv2.imread("D:/testdata/some.tif",CV_LOAD_IMAGE_COLOR)
or add r to the begining of the string
im = cv2.imread(r"D:\testdata\some.tif",CV_LOAD_IMAGE_COLOR)
I also met the same issue before on ubuntu 18.04.
cv2.imread(path)
I solved it when I changed the path argument from Relative_File_Path to Absolute_File_Path.
Hope it be useful.
just stumbled upon this one.
The solution is very simple but not intuitive.
if you use relative paths, you can use either '\' or '/' as in test\pic.jpg or test/pic.jpg respectively
if you use absolute paths, you should only use '/' as in /.../test/pic.jpg for unix or C:/.../test/pic.jpg for windows
to be on the safe side, just use for root, _, files in os.walk(<path>): in combination with abs_path = os.path.join(root, file). Calling imread afterwards, as in img = ocv.imread(abs_path) is always going to work.
In case no one mentioned in this question, another way to workaround is using plt to read image, then convert it to BGR format.
img=plt.imread(img_path)
print(img.shape)
img=img[...,::-1]
it has been mentioned in
cv2.imread does not read jpg files
This took a long time to resolve. first make sure that the file is in the directory and check that even though windows explorer says the file is "JPEG" it is actually "JPG". The first print statement is key to making sure that the file actually exists. I am a total beginner, so if the code sucks, so be it.
The code, just imports a picture and displays it . If the code finds the file, then True will be printed in the python window.
import cv2
import sys
import numpy as np
import os
image_path= "C:/python27/test_image.jpg"
print os.path.exists(image_path)
CV_LOAD_IMAGE_COLOR = 1 # set flag to 1 to give colour image
CV_LOAD_IMAGE_COLOR = 0 # set flag to 0 to give a grayscale one
img = cv2.imread(image_path,CV_LOAD_IMAGE_COLOR)
print img.shape
cv2.namedWindow('Display Window') ## create window for display
cv2.imshow('Display Window', img) ## Show image in the window
cv2.waitKey(0) ## Wait for keystroke
cv2.destroyAllWindows() ## Destroy all windows
I had a similar problem, changing the name of the image to English alphabetic worked for me. Also, it didn't work with a numeric name (e.g. 1.jpg).
My OS is Windows 10. I noticed imread is very sensitive to path. No any recommendation about slashes worked for me, so how I managed to solve problem: I have placed file to project folder and typed:
img = cv2.imread("MyImageName.jpg", 0)
So without any path and folder, just file name. And that worked for me.
Also try different files from different sources and of different formats
I spent some time on this only to find that this error is caused by a broken image file on my case. So please manually check your file to make sure it is valid and can be opened by common image viewers.
I had a similar issue,changing direction of slashes worked:
Change / to \
In my case helped changing file names to latin alphabet.
Instead of renaiming all files I wrote a simple wrapper to rename a file before the load into a random guid and right after the load rename it back.
import os
import uuid
import cv2
uid = str(uuid.uuid4())
def wrap_file_rename(my_path, function):
try:
directory = os.path.dirname(my_path)
new_full_name = os.path.join(directory, uid)
os.rename(my_path, new_full_name)
return function(new_full_name)
except Exception as error:
logger.error(error) # use your logger here
finally:
os.rename(new_full_name, my_path)
def my_image_read(my_path, param=None):
return wrap_file_rename(my_path, lambda p: cv2.imread(p) if param is None else cv2.imread(p, param))
Sometimes the file is corrupted. If it exists and cv2.imread returns None this may be the case.
Try opening the file כfrom file explorer and see if that works
I've run into this. Turns out the PIL module provides this functionality.
Similarly, numpy.imread and scipy.misc.imread both didn't exist until I installed PIL
In my configuration (win7 python2.7), that was done as follows:
cd /c/python27/scripts
easy_install PIL
I have just started with using IPython Notebook and have been fascinated by its power. I have been using a few examples available on the net to get started with. I was following this tutorial: http://nbviewer.ipython.org/url/finiterank.com/cuadernos/suavesylocas.ipynb but the maths output is not getting rendered as expected. Below is the my code and the output:
In [30]:
%load_ext sympyprinting
%pylab inline
from __future__ import division
import sympy as sym
from sympy import *
init_printing()
x,y,z=symbols("x y z")
k,m,n=symbols("k m n", integer=True)
The sympyprinting extension is already loaded. To reload it, use:
%reload_ext sympyprinting
Welcome to pylab, a matplotlib-based Python environment [backend: module://IPython.kernel.zmq.pylab.backend_inline].
For more information, type 'help(pylab)'.
In [31]:
t = sin(2*pi*x*(k**2))/ (4*(pi**2)*(k**5)) + (x**2) / (2*k)
t
Out[31]:
2 ⎛ 2 ⎞
x sin⎝2⋅π⋅k ⋅x⎠
─── + ─────────────
2⋅k 2 5
4⋅π ⋅k
I have tried other examples also, and they are also not getting rendered properly. Where am I going wrong?
I had the same problem. Try
from sympy.interactive import printing
printing.init_printing(use_latex=True)
instead of
%load_ext sympyprinting
I am using sympy 0.7.2
I recently had the same problem, and I'm using Linux Crunchbang, which is a derivative of Redhat I think. Originally I installed sympy using
pip install sympy
However, this led to the above problem as described. So then I went to the sympy webpage and cloned the git repository to a folder. Then it can be installed (once in the local folder) by using
python setup.py install
After that everything worked fine, so I think it had something to do with the version used. For the record, the commands I used to initialize the printing in python were
import sympy
sympy.init_printing()
Import:
from sympy import *
init_printing()
Example:
x = symbols('x')
a = Integral(cos(x)*exp(x), x)
Eq(a, a.doit())
Output: