x + x[::-1]
where
W[2,3,1,4,0,0,1] >>> [0,0,1,1,1,2,3,3,3,3,6]
unrepeat
margin-left: 5px
join each of one to other
head
u
quit
count occurence
1ċ[1,1,1,1,2,2,3] >>> 4
[1,1,1,1,2,2,3]
[1, 2, 3, 4, 1, 2, 1]
order
each left
each right
iota
enclose
reshape
pair
[w, x]
[x]
⍳4 >>> [0,1,2,3] ⍳[4,4] >>> [[[0,0], [0,1], [0,2], [0,3]], [[1,0], [1,1], [1,2], [1,3]], [[2,0], [2,1], [2,2], [2,3]], [[3,0], [3,1], [3,2], [3,3]]]
1 2 3#/:4 5 6
1 2 3#4
1 2 3#5
1 2 3#6
#