Improve error message when trying to view a dataframe and Pandas is not installed next to Spyder

Issue Report Checklist

• [ yes] Searched the issues page for similar reports
• [ yes] Read the relevant sections of the Spyder Troubleshooting Guide and followed its advice
• Reproduced the issue after updating with conda update spyder (or pip, if not using Anaconda)
• Could not reproduce inside jupyter qtconsole (if console-related)
• Tried basic troubleshooting (if a bug/error)
  • Restarted Spyder
  • Reset preferences with spyder --reset
  • Reinstalled the latest version of Anaconda
  • Tried the other applicable steps from the Troubleshooting Guide
• Completed the Problem Description, Steps to Reproduce and Version sections below

Problem Description

After opening spyder in virtualenv, checked pip freeze and lists pandas , numpy , sklearn everything needed for data analysis the i wrote a code and ran it. it worked well., but when i am trying to open same variable in variable explorer window, it showing error

What steps reproduce the problem?

1. install spyder using pip
2. open spyder in virtualenv
3. ran the code and check in variable explorer

What is the expected output? What do you see instead?

IPython console is working fine and giving perferct results, only variable explorer is not able to open variables that are coming form using pandas library i tired defining numpy array and list , i could able to open them as below

but when i am trying open pandas dataframe variable , variable explorer is throwing below error

Paste Traceback/Error Below (if applicable)

PASTE TRACEBACK HERE

Versions

• Spyder version: 4.1.2
• Python version: 3.8
• Qt version:
• PyQt version:
• Operating System name/version: Windows 10

Dependencies

# Mandatory:
atomicwrites >=1.2.0           :  1.4.0 (OK)
chardet >=2.0.0                :  3.0.4 (OK)
cloudpickle >=0.5.0            :  1.4.0 (OK)
diff_match_patch >=20181111    :  20181111 (OK)
intervaltree                   :  None (OK)
IPython >=4.0                  :  7.13.0 (OK)
jedi =0.15.2                   :  0.15.2 (OK)
nbconvert >=4.0                :  5.6.1 (OK)
numpydoc >=0.6.0               :  0.9.2 (OK)
paramiko >=2.4.0               :  2.7.1 (OK)
parso =0.5.2                   :  0.5.2 (OK)
pexpect >=4.4.0                :  4.8.0 (OK)
pickleshare >=0.4              :  0.7.5 (OK)
psutil >=5.3                   :  5.7.0 (OK)
pygments >=2.0                 :  2.6.1 (OK)
pylint >=0.25                  :  2.5.0 (OK)
pyls >=0.31.9;<0.32.0          :  0.31.10 (OK)
qdarkstyle >=2.8               :  2.8.1 (OK)
qtawesome >=0.5.7              :  0.7.1 (OK)
qtconsole >=4.6.0              :  4.7.3 (OK)
qtpy >=1.5.0                   :  1.9.0 (OK)
sphinx >=0.6.6                 :  3.0.3 (OK)
spyder_kernels >=1.9.0;<1.10.0 :  1.9.0 (OK)
watchdog                       :  None (OK)
zmq >=17                       :  19.0.0 (OK)

# Optional:
cython >=0.21                  :  None (OK)
matplotlib >=2.0.0             :  None (OK)
numpy >=1.7                    :  1.18.2 (OK)
pandas >=0.13.1                :  None (OK)
scipy >=0.17.0                 :  None (OK)
sympy >=0.7.3                  :  None (OK)

[bcolsen]

I think the error message should explain the situation. Something like optional dependency <package> not found in spyder environment

I would also be ok with them being mandatory.

[maximlt]

I encountered the same bug and it took me a while before I understood what went wrong and to find this issue eventually. I use the Variable Explorer mostly to explore DataFrames so I would expect this feature to work out-of-the-box, thus I’m +1 on having Pandas (hence Numpy) as a hard dependency here.

Note that even if pandas isn’t installed the DataFrame shows up in the Variable Explorer, it’s even able to parse it somehow without pandas as the column names are displayed.

Are there other types of object that could lead to the same error besides the Numpy and Pandas ones?

I’ll update the wiki (see #12107) according to your decision here.