Vocabulary/commadot
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,. y Ravel Items
Rank Infinity -- operates on x and y as a whole, by items of y -- WHY IS THIS IMPORTANT?
Creates a table where each row of the table comes from an item of y.
Converts an atom to a (1-by-1) table
$ ,. 'a' 1 1
Converts a list to a 1-column table
] ,. i.3 0 1 2
Converts a table to itself (i.e. unchanged)
] z=: 3 4 {. i. 2#10 NB. self-indexing table
0 1 2 3
10 11 12 13
20 21 22 23
z -: ,.z
1
Converts an array of rank 3 or higher to a table
] z=: 2 3 4 {. i. 3#10 NB. self-indexing brick
0 1 2 3
10 11 12 13
20 21 22 23
100 101 102 103
110 111 112 113
120 121 122 123
,.z
0 1 2 3 10 11 12 13 20 21 22 23
100 101 102 103 110 111 112 113 120 121 122 123
Common Uses
1. Arrange the atoms of a list of boxed strings vertically for easier reading
d +------------------------------------------+--------... |The curfew tolls the knell of parting day,|The lowi... +------------------------------------------+--------... ,. d +-------------------------------------------+ |The curfew tolls the knell of parting day, | +-------------------------------------------+ |The lowing herd wind slowly o'er the lea | +-------------------------------------------+ |The ploughman homeward plods his weary way,| +-------------------------------------------+ |And leaves the world to darkness and to me.| +-------------------------------------------+
Related Primitives
Ravel (,)
More Information
1. When y is an array, ,.y applies Ravel (,) to each item of y — which gives the monad (,.) its name.
x ,. y Stitch
Rank Infinity -- operates on x and y as a whole, after adjusting the smaller operand -- WHY IS THIS IMPORTANT?
Joins each item of x to the corresponding item of y
x ; y =: toupper x=: 3 5 $ 97}.a. +-----+-----+ |abcde|ABCDE| |fghij|FGHIJ| |klmno|KLMNO| +-----+-----+ x ,. y abcdeABCDE fghijFGHIJ klmnoKLMNO
If x or y is an atom, it is appended to each item of the other
x ,. '/'
abcde/
fghij/
klmno/
'\' ,. y
\ABCDE
\FGHIJ
\KLMNO
Common uses
1. Create a two-column table from two lists, or from a list and an atom
1 2 3 ,. 5 6 7 1 5 2 6 3 7 1 2 3 ,. 4 1 4 2 4 3 4 10 ,. 1 2 3 10 1 10 2 10 3
2. Attach an index column to a table
]z=: 5 3 {. i.10 10 NB. sample noun
0 1 2
10 11 12
20 21 22
30 31 32
40 41 42
(_ ,. z) ,.~ i. #z NB. uses (_) as a column separator
0 _ 0 1 2
1 _ 10 11 12
2 _ 20 21 22
3 _ 30 31 32
4 _ 40 41 42
3. Prefix a space (or other character) to each line of a literal table
] z=: > ;: 'this is a matrix' this is a matrix ' ' ,. z this is a matrix
Related Primitives
Append (,), Laminate (,:), Raze (;)
More Information
1. x ,. y is exactly equivalent to x ,"_1 y .
Use These Combinations
Combinations using x ,. y that have exceptionally good performance include:
What it does Type;
Precisions;
RanksSyntax Variants;
Restrictions
Benefits;
Bug Warnings
Combine axes 1 and 2 ,./ y linear time Join contents of boxed items along axis 1 ,.&.>/ y