JuliaLang/julia

Ellipsis slicing

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#5,405 创建于 2014年1月15日

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 (29 评论) (8 反应) (0 负责人)Julia (48,709 star) (5,773 fork)batch import
arrayshelp wantedparser

描述

Numpy has this ellipsis notation for filling index tuples up to dimension, where in A[..., i, k] ... is interpreted as shorthand for the number of colons :, :, : etc needed to fill the indexing tuple up to dimension n.

http://docs.scipy.org/doc/numpy/reference/arrays.indexing.html

This gives nice access to contiguous subarrays in the dense array case and would be not more harmful than the : notation itself.

Was this feature already considered? It was mentioned by @toivoh on the mailing list, but did not trigger discussion.

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backend
议题类型
feature
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
4
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stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
Julia array indexingJulia parser internalsNumpy ellipsis notation
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
15
研究方向
Investigate how Julia currently handles array indexing with ':' and n dimensional slices. Look at the parser and indexing implementation in Julia's source (e.g., `src/julia parser.scm` or `base/abstractarray.jl`). Consider how to parse '...' as an operator that expands to appropriate number of colons. Study numpy's implementation for reference. Check existing comments in the issue for suggested approaches.