---
title: "Column types"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Column types}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---




```r
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> 2021-07-30
#> $ POSIXt        <dttm> 2021-07-30 04:11:25
#> $ 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()`:


```r
pillar:::type_sum.default
```
