错误：AttributeError：模块“numpy”没有属性“sqrt”

Question

import numpy as np
np. sqrt(3)

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-14-029a7ac454da> in <module>()
      1 import numpy as np
----> 2 np. sqrt(3)

AttributeError: module 'numpy' has no attribute 'sqrt'

I know it's basic but please guide. I am new to python 3.

Answer 1

Make sure that you don't have a file named numpy.py in your workspace.

(test-py38) gino:test$ touch numpy.py
(test-py38) gino:test$ ll
total 0
-rw-r--r-- 1 gino gino 0  6月 10 12:30 numpy.py

(test-py38) gino:test$ ipython
Python 3.8.3 (default, May 14 2020, 20:11:43) 
...

In [1]: import numpy as np 

In [2]: np. sqrt(3)                                                                                                     
---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-2-54486447ed79> in <module>
----> 1 np. sqrt(3)

AttributeError: module 'numpy' has no attribute 'sqrt'

You must not have files named after Python packages because import will import your file instead of the actual package. You need to rename them to something else.

See the Module Search Path docs for info how Python imports stuff:

When a module named spam is imported, the interpreter first searches for a built-in module with that name. If not found, it then searches for a file named spam.py in a list of directories given by the variable sys.path .

• The directory containing the input script (or the current directory when no file is specified).
• PYTHONPATH (a list of directory names, with the same syntax as the shell variable PATH).
• The installation-dependent default.

You could also check that it's importing the correct package by printing __path__ :

(test-py38) gino:test$ ipython
Python 3.8.3 (default, May 14 2020, 20:11:43) 
...

In [1]: import numpy as np

In [2]: np.__path__                                                                                                     
Out[2]: ['/path/to/.venvs/test-py38/lib/python3.8/site-packages/numpy']

In [4]: np.  sqrt(3)     # The spaces don't matter                                                                      
Out[4]: 1.7320508075688772