Thread

Anecdotally, programmers dislike "reduce"

175 points · 283 comments · vinhnx

RomanKornev · 1789606146 · focus · HN ↗
Every single `reduce` can be replaced with a more intuitive `groupBy`, `partition`, `mapValues`, `keyBy`, etc.
Reduce can approximate anything, that doesn't mean we should use it.
My favorite antipattern is
```
  items.reduce(
    (acc, item) =&gt; ({
      ...acc,
      [item.id]: item,
    }), {}
  );
```
Like, why? Not only is this ridiculously inefficient O(N^2), it's also longer and less understandable than "build a new map" version.
1. tehnub · 1789619225 · focus · HN ↗
  This one doesn't seem expressible in those terms:
  from functools import reduce df = reduce(DataFrame.union, dfs)

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