Building a matrix of Profile Expression

Question

[grecoandreauni]

allright so... i'm a college student who has to write a code in R that search the GEO and SRA database for data selected by a user and then i have to "build a matrix that put all the expression profile together"

i already wrote some code using bioconductor that enable the user to search and download data from these two databases,

but the problem is that i don't understand what my professor meant with the second part, am i supposed to just put the data from multiple GEO and SRA file together?

[ddiez]

Basically, if I understand correctly, to create a matrix in which each column represents a sample and the rows the genes/transcripts/probes (depending on your level of summarization), and the corresponding values in the matrix are the expression levels (assumed you are talking about gene expression profiling).