bool(MultiIndex) seems to always return False · Issue #7897 · pandas-dev/pandas (original) (raw)

Skip to content

Navigation Menu

• • GitHub Copilot Write better code with AI
  • GitHub Advanced Security Find and fix vulnerabilities
  • Actions Automate any workflow
  • Codespaces Instant dev environments
  • Issues Plan and track work
  • Code Review Manage code changes
  • Discussions Collaborate outside of code
  • Code Search Find more, search less
• Explore
  • Learning Pathways
  • Events & Webinars
  • Ebooks & Whitepapers
  • Customer Stories
  • Partners
  • Executive Insights
• • GitHub Sponsors Fund open source developers
  • The ReadME Project GitHub community articles
• • Enterprise platform AI-powered developer platform
• Pricing

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Sign up

Appearance settings

Description

This means that patterns such as:

if my_frame.index: # do something

with my_frame having a MultiIndex will never enter the if block. One can check that bool(my_frame.index) returns False. A single index (pandas.Index) will (correctly IMO) raise a ValueError warning that the truth value of an array is ambiguous. However, a MultiIndex fails silently.

This is such an awesome source of silent bugs that I'm surprised this hasn't come up before. Is there any reason why we want bool to return False every time for a MultiIndex?