[R] Fill an empty matrix with a function
Maximilian Eckert
maximilian.eckert03 at gmail.com
Sun Dec 4 13:43:47 CET 2016
Dear Sir oder Madam,
I am currently writing my master thesis and I am struggling with R:
I have created an empty matrix (M) which has months as row.names and stocks
as column.names and now I want to fill this matrix with values from another
matrix (T). The matrix T has also months as row.names and stocks as
column.names however here I have several values for each month. Now I want
to count the values which have values bigger or equal to zero (plus 1) and
add them to my matrix M:
If I do it manually it would look like:
M[,1] <- t(array((colSums(T[1:22,] > 0))+1)) #here in Matrix T I have 22
values for the month January
M[,2] <- t(array((colSums(T[23:53,] > 0))+1)) #here in Matrix T I have 30
values for the monh February
Is there a way to do this without a loop as I have a very large data set? I
tried to merge it however it did not work:
merge.default(as.data.frame(M), as.data.frame(T), by = "row.names",
function(x){colSums(T[,]>0)+1})
Thank you very much,
Max
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