I do not think your wetware processed the inputs correctly. The second
bit should not have been flipped:
Try this loop free index based solution:
b <- c( 1, 0, 1, 0, 1, 0, 1, 0, 1, 0)
r <- b
r[p] <- 0 + !r[p] # adding 0 converts logical TRUE/FALSE to 0/1
r
[1] 0 0 0 0 0 0 0 0 1 0
The "if" statement is for control but you might have succeeded with an
ifelse function which is generally more useful for conditional
modification of vectors. It could have been used if the transformation
were not binary.
--
David Winsemius
On Apr 19, 2009, at 3:24 PM, Esmail wrote:
I have a string of binary values, and I would like to flip certain
bits in a set of positions.
Let's say the
vector p contains position [1, 3, 5, 7]
vector b contains bits [1, 0, 1, 0, 1, 0, 1, 0, 1, 0]
result r should be [0, 1, 0, 0, 0, 0, 0, 0, 1, 0]
in pseudo code this would be something like
---
r = c()
for (i in 1:10)
if (i in p)
r = c(r, flip[i])
r
----
doesn't work :-) R doesn't like the if statement.
Is there a nice, concise way to do this? The vector contents and
size will vary, but length of p <= b.
Thanks,
Esmail
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