runtimecompare approaches one problem · two ways
Compare Approaches
The same problem solved different ways in Python, run on the same input, with what really differs and when to use each.
Python loops vs pandas
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what differs
The loop handles one row at a time in Python. pandas filters with a boolean mask over the whole column and groups in compiled code.
at a glance
| approach | use it when |
|---|---|
| A · loop over rows | Small data, simple logic, or no pandas available. |
| B · pandas | Anything beyond a few thousand rows, or several steps of analysis. |
Watch out: Float sums can differ in the last digits when added in a different order; both round before printing.
the outputs
Each approach runs on the same input.
concepts
vectorisationboolean masksgroupby
learn it
Filtering rows · Group and aggregate
related comparisons
pandas groupby vs SQL GROUP BY · DataFrame.apply vs vectorised columns