c function error in R

I am trying to conduct factorial ANOVA test on R for 2*2 factors ('Sex', 'Avatar', both between-subject factors) and it keeps showing error

formal argument "between" matched by multiple actual arguments

library(ez)
m = ezANOVA(dv=Positives, between=Sex, between=Avatar, wid=Subject, data=avt)

Assignment tip was:

Pass both Sex and Avatar as the between parameter using a vector created with the "c" function.

I tried to use c(between = Sex, between = Avatar), it doesn't work either.

Please, may I ask for help on this code? Many thanks!

Solution

In such cases it is always worth trying to RTM.

It says

If a single value, may be specified by name alone; if multiple values, must be specified as a .() list.

see https://cran.r-project.org/web/packages/ez/ez.pdf

The manual also has an example, which goes like this:

#Run an ANOVA on the mean correct RT data.
rt_anova = ezANOVA(
    data = ANT[ANT$error==0,]
    , dv = rt
    , wid = subnum
    , within = .(cue,flank)
    , between = group
)

So you should probably try

m = ezANOVA(dv=Positives, between=.(Sex, Avatar), wid=Subject, data=avt)