Selecting the statistically significant variables in an R glm model

Question

I have an outcome variable, say Y and a list of 100 dimensions that could affect Y (say X1...X100).

After running my glm and viewing a summary of my mod

Answer 1

in

sig.formula <- as.formula(paste("y ~",relevant.x))

you paste only the first variable of relevant.x the others are ignored (try for example to invert the condition to >0.5)