This is my very first experience with sympy. I am usingDEbian bullseye with pythong. I installed git then "git clone https://github.com/sympy/sympy.git" Following that:
abraca#SS:~/SymPy$ python3
Python 3.9.2 (default, Feb 28 2021, 17:03:44)
[GCC 10.2.1 20210110] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from sympy import *
>>> x = symbols('x')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'symbols' is not defined
>>> quit()
What have I done wrong?
Here is what my tree looks like, starting from my root directory:
abraca#SS:~$ ls SymPy/sympy/sympy
abc.py core integrals polys tensor
algebras crypto interactive printing testing
assumptions diffgeom liealgebras release.py this.py
benchmarks discrete logic sandbox unify
calculus external matrices series utilities
categories functions multipledispatch sets vector
codegen galgebra.py ntheory simplify
combinatorics geometry parsing solvers
concrete holonomic physics stats
conftest.py __init__.py plotting strategies
Installing sympy via git never worked. Here is what did work (note the all important 3, placed after python, not pip):
sudo apt install python3-pip
pip3 install sympy
From then on it all works:
abraca#SS:~$ python3
Python 3.9.2 (default, Feb 28 2021, 17:03:44)
[GCC 10.2.1 20210110] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>> from sympy import *
>>> x=symbols('x')
>>> limit(sin(x)/x,x,0)
1
>>> quit()
abraca#SS:~$
Related
When trying to install pgadmin4 in desktop mode on my Ubuntu system, I received a ModuleNotFoundError for _ctypes.
I did some research and found that _ctypes requires the libffi-dev package to be installed. However it seems that libffi-dev and thus _ctypes was installed for Python 2.7, when I run import ctypes it seems to work:
$ python2
Python 2.7.15+ (default, Nov 27 2018, 23:36:35)
[GCC 7.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import ctypes
>>>
When I try to do the same for Python 3.7, it doesn't work:
$ python
Python 3.7.3 (default, Jun 21 2019, 12:46:58)
[GCC 7.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import ctypes
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python3.7/ctypes/__init__.py", line 7, in <module>
from _ctypes import Union, Structure, Array
ModuleNotFoundError: No module named '_ctypes'
How could I add the module _ctypes to my Python 3.7 configuration?
If you install python from source file, you have to install some required packages manually as mentioned in https://superuser.com/questions/1412975/how-to-build-and-install-python-3-7-x-from-source-on-debian-9-8.
Actually you are supposed to see some errors after make due to libffinot found as shown in the screenshot below. However, you can still run make install despite the error. When you open python after the installation and import the module, it then gives you such error.
To solve this problem, you can install the dependent package i.e libffi or libffi-devel(redhat) prior to ./configure, make and make install as mentioned in:
Package libffi was not found in the pkg-config search path REDHAT6.5 and
https://bugs.python.org/issue31652.
I have installed graph-tool:
brew --prefix graph-tool
'/usr/local/opt/graph-tool
but when trying to import it:
Python 3.6.4 |Anaconda, Inc.| (default, Jan 16 2018, 12:04:33)
[GCC 4.2.1 Compatible Clang 4.0.1 (tags/RELEASE_401/final)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from graph_tool.all import *
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'graph_tool'
:(
Does anyone have a solution for this?
Thanks
Homebrew installs the library using its own Python interpreter, which has its module path somewhere in /usr/local/opt/. You are using the anaconda Python interpreter, which knows nothing about homebrew-installed modules. The solution here is simply to use homebrew's Python interpreter, not anaconda's.
After installing pandas am able to import in cmd as below :
C:\Users\me\Desktop\Django_Project>python
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:59:51) [MSC v.1914 64 bit
(AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import pandas
>>>
But when am importing pandas in Spyder in IPython 6.5.0 console I get below error:
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:06:47) [MSC v.1914 32 bit (Intel)]
Type "copyright", "credits" or "license" for more information.
IPython 6.5.0 -- An enhanced Interactive Python.
c:\program files (x86)\python37-32\lib\site-packages\ipykernel\parentpoller.py:116: UserWarning: Parent poll failed. If the frontend dies,
the kernel may be left running. Please let us know
about your system (bitness, Python, etc.) at
ipython-dev#scipy.org
ipython-dev#scipy.org""")
In [1] : import pandas
Traceback (most recent call last):
File "<ipython-input-1-38d4b0363d82>", line 1, in <module>
import pandas
ModuleNotFoundError: No module named 'pandas'
In [2] :
Note: I have installed python in "C:\Users\me\AppData\Local\Programs\Python\Python37\" path and environment variables is set as "C:\Users\me\AppData\Local\Programs\Python\Python37;"
And I installed pandas using PIP
Please suggest the solution to resolve this issue.I have tried reinstalling the pandas package almost 6-7 times.
I think you should open anaconda command prompt by searching it in windows search bar . Now write there "conda install -c anaconda pandas" and try again to run the program
I am unable to dynamically import a module which I have no problem importing in code and I have no idea why.
I have the following:
> ls lib
__init__.py main.py
The init file is empty. The following works:
> python3
Python 3.4.3 (default, Oct 14 2015, 20:28:29)
[GCC 4.8.4] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import lib.main
>>> lib.main.sayyay()
yay
The following does not work:
> python3
Python 3.4.3 (default, Oct 14 2015, 20:28:29)
[GCC 4.8.4] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import importlib
>>> importlib.import_module("lib.main")
<module 'lib.main' from '/some/path/lib/main.py'>
>>> lib.main.sayyay()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'lib' is not defined
I did read the importlib documentation as well as a couple of answers here on SO, e.g., How to import a module in Python with importlib.import_module and Dynamically import a method in a file, from a string
But what am I missing?
import_module returns the imported module.
Therefore, you need to give the imported module a name and use this just like lib.main
>>> lib_main = importlib.import_module("lib.main")
>>> lib_main.sayyay()
I have python 2.7.12 installed in Ubuntu 16.04 (64-bit version). I have modules such as numpy, scipy, sympy etc. installed via pip as well. My problem is, when I open python command line via Terminal and try to import these modules, I get the following error:
$ python
Python 2.7.12 (default, Jul 10 2016, 20:42:07)
[GCC 5.3.1 20160413] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named numpy
>>>
Upon doing some research, I found from this thread that if I open python command line using /usr/bin/python and try importing these modules, I don't get any errors.
$ /usr/bin/python
Python 2.7.11+ (default, Apr 17 2016, 14:00:29)
[GCC 5.3.1 20160413] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy
>>> import scipy
>>> import sympy
>>> import matplotlib
>>> import pandas
>>>
But I would like to know if there is any way I can just type in python from Terminal and import these modules in the python command line? For example, if I write a program like this,
x = 2
print x
y = 5
print y
print x+y
import numpy
import scipy
import sympy
save it in a file named test.py in my desktop and open it using the command /usr/bin/python test.py, I am getting the desired output.
$ /usr/bin/python test.py
2
5
7
But if I try the same with the command python test.py, I get the error again
$ python test.py
2
5
7
Traceback (most recent call last):
File "test.py", line 8, in <module>
import numpy
ImportError: No module named numpy
From what I understand, python doesn't have access to system wide modules since it is installed locally. If so, is there a way to make python global or the modules local to python? I have been trying for the past couple of hours to find a solution but I haven't found anything yet and I am new to Linux. Thanks for your help.
I think the root cause is you have several python binary under $PATH, and your system doesn't use /usr/bin/python by default.
run command which python to see which python is used by default
rename the default python file to something like 'python-2-7-12'
then try to run python test.py again to see if it is resolved.