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datacarpentry / python-ecology-lesson

Data Analysis and Visualization in Python for Ecologists
https://datacarpentry.org/python-ecology-lesson
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Ordering of left/right does not matter for *any* join #429

Closed maneesha closed 1 year ago

maneesha commented 4 years ago

The Combining DataFrames with Pandas notes that:

For inner joins, the order of the left and right arguments does not matter.

However, this is true of all joins. I would suggest modifying this text to reflect this. Otherwise it is misleading and implies that it may matter for other types of joins.

maxim-belkin commented 4 years ago

I believe order matters for left and right (outer) joins. Could you please clarify your point?

btovar commented 1 year ago

@maneesha Thank you for your report. Order does matter for certain joins, e.g., the left join preserves all rows for the left argument, so I'm closing this one.