How to build a Term-Document-Matrix from a set of texts and a specific set of terms (tags)?

Question

I have two sets of data:

• a set of tags (single words like php, html, etc)

• a set of texts

I wish now

Answer 1

DocumentTermMatrix(docs, list(dictionary = Dictionary$Var1)) 

You could pre-defined the dictionary using the set tags

Answer 2

tdm.onlytags <- tdm[rownames(tdm)%in%TagSet$tag,]

to select only your specified words and next proceed with your analysis.