HOw to achieve big vector times big dataframe in R?
apply((t(as.matrix(b)) * a), 2, sum) should do what you want. Why this works; see, http://cran.r-project.org/doc/manuals/r-release/R-intro.html#The-recycling-rule and the paragraph before that. Jan Tammy Ma <metal_licaling at live.com> schreef:
HI, I have the following question: Vector a with lenght 150 A B C D......... dataframe b with dim 908X150 1 1 1 1..... 2 2 2 2 3 3 3 3 4 4 4 4 ................ final result I want is the vector with length 908: A*1+B*1+C*1+D*1+..... A*2+B*2+C*2+D*2+..... A*3+B*3+C*3+D*3+..... A*4+B*4+C*4+D*4+..... .... because of too large dimension, how can I achieve this in R? Thanks. Kind Regards, Tammy [[alternative HTML version deleted]]
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