ifor evaluates an expression within a for loop, after applying
iter to the sequence. ifor also allows multiple indexes by
separating each variable name with a ".", such that ifor(x, i.j, ...)
is similar to for (i,j in x) ... if for loops accepted multiple
index values. See comprehension for more details. Assignment to
a variable outside of the function can be accomplished through assign or <<-.
Usage
ifor(ind, x, expr)
Arguments
ind
variable name whose values are updated each round in the loop. Separate names with "." to allow for multiple variables
x
sequence over which to loop
expr
expression that is evaluated each round within the loop