On Aug 15, 2010, at 4:47 AM, pablo.andrade wrote:
Hi,
Is there any function to replace colProds that finds column-wise
products of
a matrix?
Or is there any other function that would give a better solution this
problem ?
I have a matrix and an array, example:
a
GSM1.CEL GSM2.CEL GSM1.CEL
10000_at 1 3 1
10001_at 3 3 3
b
10000_at 10001_at
1 3
I want to find the number of occurrences of this array within the
matrix
(which in this case is 2).
a==b
gives me:
GSM1.CEL GSM2.CEL GSM1.CEL
10000_at TRUE FALSE TRUE
10001_at TRUE TRUE TRUE
What I have done is :
colProds(a==b)
GSM1.CEL GSM2.CEL GSM1.CEL
1 0 1
sum(colProds(a==b))
2 -----> that gives the value of 2 that I want.
The problem is: if the matrix "a" is actually a vector (matrix 1xN),
This is a theory untested in the absence of a reproducible example
that reproduces the faulty behavior. You may want to look at what is
offered by the help page:
?"["
... especially the drop argument. You can prevent single column
matrices from being "vectorized" by using drop = FALSE.
the
function "colProds" multiply the elements of the row as if it was a
column:
a
10000_at
1
b
GSM1.CEL GSM2.CEL GSM1.CEL
1 3 1
a==b
GSM1.CEL GSM2.CEL GSM1.CEL
TRUE FALSE TRUE
colProds(a==b)
[1] 0
I could use a if length(b==1) find sum(a==b) instead of
sum(colProds(a==b)),
but I would have to use this condition many time through the code,
so I
would like to know if there a better way to do that.
Thank you very much.
Pablo.
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