[R] Comparing each component of vector to each component of a Matrix.

Sven E. Templer sven.templer at gmail.com
Wed Mar 11 08:26:40 CET 2015


you didn't specify values in A, and you first wanted to compare bi
with Aij, but then also which bi is less/equal to zero.

For the first case, with

A <- matrix(0:3,2)
b <- seq(-1,5)

and a comparison function for bi less/equal to Aij like

f <- function (bi) {as.integer(bi<=A)}

you can iterate along b with

lapply(b, f) # contains results as matrices in a list, each with same
dimensions as A
sapply(b, f) # aligns results to an length(A)*length(b) matrix


On 11 March 2015 at 08:01, Frederic Ntirenganya <ntfredo at gmail.com> wrote:
> Hi All,
> I need a help on a loop which can compare the each component of vector to
> each component of a Matrix.
> Let a vector b = {b1, b2, ...,bn} and 2x2  matrix A = Aij.
> I need to compare each component of the vector with each component of a
> matrix and print 1 if the component is less or equal to one and print 0
> otherwise.
> bi <= Aij, print 1 and 0 otherwise.
> Any help is appreciated.
> Regards,
> Frederic.
> Frederic Ntirenganya
> Maseno University,
> African Maths Initiative,
> Kenya.
> Mobile:(+254)718492836
> Email: fredo at aims.ac.za
> https://sites.google.com/a/aims.ac.za/fredo/
>         [[alternative HTML version deleted]]
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