Projection、Key Extraction 与“按字段操作” | STL
本章覆盖：sort by field；find by condition；comparator duplication；projection concept；C++20 ranges projection；`ranges::sort(items, {}, &Type::field)`；member pointer；key extraction；减少手写 comparator；传统 algorithm 与 Ranges API 差异连接。
本章知识点
- sort by field
- find by condition
- comparator duplication
- projection concept
- C++20 ranges projection
ranges::sort(items, {}, &Type::field)- member pointer
- key extraction
- 减少手写 comparator
- 传统 algorithm 与 Ranges API 差异连接