grid.table and tableGrob in gridExtra package

Question

I am trying to format the table using gridExtra package. The gridExtra package I have is 2.0 and R version is 3.2.1

I was goin

Answer 1

This recent answer shows how to alter the parameters, and Baptiste gives a link to further examples. As you notice in your question, to alter the formatting you use the theme argument; you can see what parameters to alter by looking at the output of ttheme_default()

# New theme paramters
myt <- ttheme_default(
         # Use hjust and x to left justify the text
         # Alternate the row fill colours
                 core = list(fg_params=list(hjust = 1, x=1),
                             bg_params=list(fill=c("yellow", "pink"))),

         # Change column header to white text and red background
                 colhead = list(fg_params=list(col="white"),
                                bg_params=list(fill="red"))
 )

# Example data - create some large numbers  
dat <- mtcars[1:5,1:5]
dat$mpg <- dat$mpg*1000

grid.newpage()
grid.draw(tableGrob(format(dat, big.mark=","), theme=myt, rows=NULL))

The big.mark argument of format is used to add the comma separator, and rownames are removed using the rows=NULL argument.