# Column types

    library(tibble)

## Overview

This vignette shows an overview of known data types and their abbreviations, and their origin. For example, `<int>` in the header of a column indicates an integer column, and `<chr>` denotes a character column.

Class | Data type | Example | Column header
--- | --- | --- | ---
Atomic | logical | `TRUE` | lgl
| integer | `1L` | int
| double | `1.5` | dbl
| character | `"A"` | chr
| complex | `0+1i` | cpl
| raw | `as.raw(1)` | raw
| list | `list(1)` | list
| named list | `list(a = 1)` | named list
Built-in objects | factor | `factor("A")` | fct
| ordered | `ordered("a")` | ord
| Date | `Sys.Date()` | date
| POSIXt | `Sys.time()` | dttm
| difftime | `vctrs::new_duration(1)` | drtn
Objects from other packages | hms | `hms::hms(1)` | time
| integer64 | `bit64::as.integer64(1e+10)` | int64
| blob | `blob::blob(raw(1))` | blob
Data frames | data.frame | `data.frame(a = 1)` | df[,1]
| tbl_df | `tibble(a = 1)` | tibble[,1]
Unchanged | AsIs | `I(1L)` | I<int>
vctrs types | unspecified | `vctrs::unspecified(1)` | ???
| vctrs_list_of | `vctrs::list_of(c(1L))` | list<int>
| vctrs_vctr | `vctrs::new_vctr(1L)` | vctrs_vc
| vctrs_partial_factor | `vctrs::partial_factor(letters)` | prtl_fctr
| vctrs_partial_frame | `vctrs::partial_frame(a = 1)` | prtl
Language objects | function | `function() NULL` | fn
| symbol | `quote(a)` | sym
| expression | `parse(text = "a <- 1\nb<- 2")` | expression
| quosures | `rlang::quos(a = 1)` | quos

## Example values

The following overview contains example values for each type:

    #> Rows: 1
    #> Columns: 23
    #> $ logical       <lgl> TRUE
    #> $ integer       <int> 1
    #> $ double        <dbl> 1.5
    #> $ character     <chr> "A"
    #> $ complex       <cpl> 0+1i
    #> $ raw           <raw> 01
    #> $ list          <list> 1
    #> $ `named list`  <named list> 1
    #> $ factor        <fct> A
    #> $ ordered       <ord> a
    #> $ Date          <date> 2023-03-19
    #> $ POSIXt        <dttm> 2023-03-19 10:23:09
    #> $ difftime      <drtn> 1 secs
    #> $ hms           <time> 00:00:01
    #> $ integer64     <int64> 10000000000
    #> $ blob          <blob> 00
    #> $ data.frame    <df[,1]> <data.frame[1 x 1]>
    #> $ tbl_df        <tibble[,1]> <tbl_df[1 x 1]>
    #> $ AsIs          <I<int>> 1
    #> $ unspecified   <???> NA
    #> $ vctrs_list_of <list<int>> 1
    #> $ vctrs_vctr    <vctrs_vc> 1
    #> $ quosures      <quos> <~1>

## Implementation

The column header is obtained by calling `pillar::type_sum()` on the column. This is an S3 method that can be overridden, but most of the time it is more useful to override `vctrs::vec_ptype_abbr()`:

    pillar:::type_sum.default
    #> function (x)
    #> {
    #>     pillar_attr <- attr(x, "pillar", exact = TRUE)
    #>     label <- pillar_attr$label
    #>     if (!is.null(label)) {
    #>         return(I(label))
    #>     }
    #>     if (is.object(x) || vec_is(x)) {
    #>         return(vec_ptype_abbr(x))
    #>     }
    #>     switch(typeof(x), builtin = , special = , closure = "fn",
    #>         environment = "env", symbol = if (is_missing(x)) {
    #>             "missing"
    #>         } else {
    #>             "sym"
    #>         }, typeof(x))
    #> }
    #> <bytecode: 0x139fbe8c8>
    #> <environment: namespace:pillar>