Align text when using tableGrob or grid.table in R

Question

When creating a table using tableGrob or grid.table. Is there way to align the text inside the table? First column to the left, and the other columns to the right? Rather than the default "center".

Thank you!

something like this: where I want column "a" alligned to the left.

a <- c("one","two","thirty five")
b <- c(1, 2, 3)
c <- c(4, 5, 6)

data <- data.frame(a,b,c)

windows()

grid.table(
  data,
  gpar.coretext=gpar(fontsize = 12),            
  gpar.coltext = gpar(fontsize = 12),            
  gpar.rowtext = gpar(fontsize = 12),            
  gpar.corefill = 
    gpar(fill = "green", alpha = 0.5, col = NA),           
  h.even.alpha = 0.5,            
  equal.width = FALSE,            
  show.rownames = FALSE,            
  show.vlines = TRUE,           
  padding.h = unit(15, "mm"),            
  padding.v = unit(8, "mm")            
) 

Answer 1

To set a "transparent" background, use the ttheme_minimal with hjust to set text alignment.

theme_1 <- ttheme_minimal(core = list(fg_params = list(hjust = 0, 
                                                           x = 0.1, 
                                                    fontsize = 9)),
                          colhead = list(fg_params = list(fontsize = 12, 
                                                          fontface = "bold")))

You can then apply the theme to the tableGrob like this:

gridExtra::tableGrob(df_tbl, theme = theme_1, rows=NULL)

Answer 2

Is this what you are looking for? There is a core.just parameter of the format() call.

require("gridExtra")

n=5
df<- data.frame(x=rnorm(n),y=rnorm(n),z=sample(letters[1:2],n,replace=T))


g1<-tableGrob(
format(df, digits = 1,
     scientific=F,big.mark = ","),
     core.just="left",
     #core.just="right",
     #col.just="right",
     gpar.coretext=gpar(fontsize=8), 
     gpar.coltext=gpar(fontsize=9, fontface='bold'), 
     show.rownames = F,
     h.even.alpha = 0,
     gpar.rowtext = gpar(col="black", cex=0.7,
                            equal.width = TRUE,
                            show.vlines = TRUE, 
                            show.hlines = TRUE,
                            separator="grey")                     
)

grid.draw(g1)

Answer 3

With gridExtra v>=2.0.0, the parameters are now controlled via nested lists (themes),

library(gridExtra)
library(grid)
n=5
d <- data.frame(x=rnorm(n),y=rnorm(n),z=sample(letters[1:2],n,replace=T))

m <- format(d, digits = 1, scientific=F,big.mark = ",")

mytheme <- ttheme_default(core = list(fg_params = list(hjust=0, x=0.1, 
                                                       fontsize=8)),
                          colhead = list(fg_params = list(fontsize=9, 
                                                          fontface="bold"))
                          )
g1 <- tableGrob(m, theme = mytheme, rows=NULL)
grid.newpage()
grid.draw(g1)