How to format numbers (comma) on a gt table

I have a gt table similar to the one in the example below. Some of the summary_rows and grand_summary_rows are comma formatted but others are not. Question: how can I format the entire gt table so that all the rows are comma formatted? I know about big.mark ="," but couldn’t find a way to add it to the code.

library(gt)
library(tidyverse)

sp500 %>%
  dplyr::filter(date >= "2015-01-05" & date <= "2015-01-16") %>%
  dplyr::arrange(date) %>%
  dplyr::mutate(week = paste0("W", strftime(date, format = "%V"))) %>%
  dplyr::select(-adj_close, -volume) %>%
  gt(
    rowname_col = "date",
    groupname_col = "week"
  ) %>%
  grand_summary_rows(
    columns = c(open, high, low, close),
    fns = list(
      min = ~min(.),
      max = ~max(.),
      avg = ~mean(.)),
    formatter = fmt_number,
    use_seps = FALSE
  )

>Solution :

Reproducible example is always welcome. With this data, you may use this code:

sp500 %>%
    dplyr::filter(date >= "2015-01-05" & date <= "2015-01-16") %>%
    dplyr::arrange(date) %>%
    dplyr::mutate(week = paste0("W", strftime(date, format = "%V"))) %>%
    dplyr::select(-adj_close, -volume) %>%
    gt(
            rowname_col = "date",
            groupname_col = "week"
    ) %>% fmt_number(columns = 2:5, decimals = 2, sep_mark = ".", dec_mark = ",") %>% 
    grand_summary_rows(
            columns = c(open, high, low, close),
            fns = list(
                    min = ~min(.),
                    max = ~max(.),
                    avg = ~mean(.)),
            formatter = fmt_number,
            use_seps = FALSE
    )

That gives the result:

2.054,44    2.054,44    2.017,34    2.020,58

Hope this help.