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Diffstat (limited to 'doc/join.md')
| -rw-r--r-- | doc/join.md | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/doc/join.md b/doc/join.md index 50a817e7..f244db59 100644 --- a/doc/join.md +++ b/doc/join.md @@ -2,7 +2,7 @@ # Join and Join To -The glyph `∾` combines arrays along an existing axis, a concept that other languages might call "concatenation" or "catenation" but BQN names "Join". The one-argument form Join and two-argument form Join To are parallel to the [functions that combine arrays along a new axis](couple.md), Merge (`>`) and Couple (`≍`). +The glyph `∾` combines arrays along an existing axis, a concept that other languages might call "concatenation" or "catenation" but BQN names "Join". The one-argument form Join and two-argument form Join To are parallel to [the functions](couple.md) that combine arrays along a new axis, Merge (`>`) and Couple (`≍`). ## Join To @@ -18,7 +18,7 @@ If the arguments have the same rank, then they are combined along the first axis For this definition to work, major cells of `𝕨` and `𝕩` have to have the same shape. That means that `𝕨≡○(1↓≢)𝕩`, and the shape of the result is the sum of the lengths of `𝕨` and `𝕩` followed by their shared major cell shape: to use a self-referential definition, the final shape is given by `+○≠ ∾ ⊣⁼○(1↓≢)` for arguments of equal rank. - a ∾ 2‿5⥊b + a ∾ 2‿5⥊b # Shapes don't fit Join To will also allow arguments with ranks that are one apart. In this case, the smaller-rank argument is treated as a major cell in its entirety. If for example `𝕨<○=𝕩`, then we must have `(≢𝕨)≡1↓≢𝕩`, and the result shape is `1⊸+⌾⊑≢𝕩`. |