Replacing the obsolete applymap with map

[quant12345]

Checklist before merging this PR:

• [x] Mentioned all issues that this PR fixes or addresses.
• [ ] Summarized the updates of this PR under Summary.
• [ ] Added an entry under Unreleased in the Changelog.

Contributes to #2435

Fixes #. Replacing DataFrame.applymap to DataFrame.map.

Removes the warning:

FutureWarning: DataFrame.applymap has been deprecated. Use DataFrame.map instead.

Summary

Replacing the obsolete applymap with map

Other Information

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 93.78%. Comparing base (5c8b366) to head (af4725e).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2436      +/-   ##
==========================================
- Coverage   93.79%   93.78%   -0.02%     
==========================================
  Files         138      138              
  Lines       14654    14640      -14     
==========================================
- Hits        13745    13730      -15     
- Misses        909      910       +1     

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[quant12345]

@dennisbader when I commit af4725e, the following tests occurred:

tests (macos-13, 3.9, all)
tests (ubuntu-latest, 3.9, all)

when merging commit 54f39f7 I see that there is, tests (ubuntu-latest, 3.8, core) and there are old versions of Pandas that led to failure and error: AttributeError: 'DataFrame' object has no attribute 'map' (that is, applymap is needed for older versions).

Are you planning to use older versions of Pandas? I can redo it like here with version processing.