# Basic Syntax

The independent is separated from the dependent ones by a tilde `~`

and the dependent variables are separated by a plus `+`

:

`Y ~ X1 + X2 + X3`

You can insert all variables of you dataset not mentioned so far with a single sign `.`

:

So the same as above can be written as:

`Y ~ .`

If you want to use all variables except one this can be excluded with the `-`

sign:

`Y ~ . - X3`

This is the same as `Y ~ X1 + X2`

.

## Dummy Variables

syntax : `as.numeric(condition)`

example: `as.numeric(data$zeit >= 48)`

## categorial variables

syntax : `as.factor(variable)`

example: `as.factor(cvar)`

## Interaction

syntax : `variable:variable`

example: `var1:var2`

The multiplication sign `var1*var2`

can be used as shortcut for `var1 + var2 + var1:var2`

.