amend

Amend

@[x;y[;f];z]
@[x;y;f[;z]]

amend is a special form of the @ verb which takes multiple arguments.

Amend takes 3 or 4 arguments, where:

• x is an array to amend
• y is the index(or indices) to amend
• f(optional), is the function to apply to those indices
• z is the second argument to f

3 argument amend always acts as an element replacement function, since f is : if it is omitted.

x can be a value or a symbol. If given a symbol, amend will modify the variable that is indicated by the symbol.

 v:1 2 3
 v
1 2 3
 @[v;1;3]
1 3 3
 v
1 2 3
 @[`v;1;3];
 v
1 3 3

ngn/k

ngn/k's amend has z as the optional argument, instead of having f as an optional argument.