<: y (Decrement)
Returns value one less than the value of y.
<: _5 1 0 5 _6 0 _1 4
Common uses
You might consider <: z-100 to be slightly less unwieldy than (z-100)-1 or alternatives.
(<: z i. ' ') { z=. 'ends: (here)'
:
y=. <:y NB. decrement yIt also helps define neater tacit definitions. Consider these two equivalent explicit definitions of a common mathematical expression:
13 : '(y-1)%y' ] %~ 1 -~ ] 13 : '(<:y)%y' <: % ]
See Also
x <: y (Less Or Equal)
Returns Boolean (0 or 1) if and only if x<=y is true.
z=: 7 8 9 z <: 8 1 1 0
Common uses
Mainly found in the logical conditions of if. statements within verb definitions:
if. x<:y do. 'x y'=. y;x end.
See Also