How to get the number of lines of a file?

[divramod]

i saw this snippet in the examples:

stl:add_item(Item({
  hl = {fg = color.bg, bg = color.fg0},
  prefix = ' ',
  suffix = ' ',
  content = core.group({core.code('l'), ':', core.code('c')})
}))

is it somehow possible to get the number of lines a file has too with core.code?

i could not find the documentation for it.

[MunifTanjim]

It's L. This is documented in :help 'statusline'.