R: Create column specification

cols {readr} | R Documentation

## Create column specification

### Description

`cols()` includes all columns in the input data, guessing the column types as the default. `cols_only()` includes only the columns you explicitly specify, skipping the rest.

### Usage

    cols(..., .default = col_guess())

    cols_only(...)

### Arguments

`...` | Either column objects created by `col_*()`, or their abbreviated character names (as described in the `col_types` argument of `read_delim()`). If you're only overriding a few columns, it's best to refer to columns by name. If not named, the column types must match the column names exactly.
`.default` | Any named columns not explicitly overridden in `...` will be read with this column type.

### Details

The available specifications are: (with string abbreviations in brackets)

- `col_logical()` [l], containing only `T`, `F`, `TRUE` or `FALSE`.

- `col_integer()` [i], integers.

- `col_double()` [d], doubles.

- `col_character()` [c], everything else.

- `col_factor(levels, ordered)` [f], a fixed set of values.

- `col_date(format = "")` [D]: with the locale's `date_format`.

- `col_time(format = "")` [t]: with the locale's `time_format`.

- `col_datetime(format = "")` [T]: ISO8601 date times

- `col_number()` [n], numbers containing the `grouping_mark`

- `col_skip()` [_, -], don't import this column.

- `col_guess()` [?], parse using the "best" type based on the input.

### See Also

Other parsers: `col_skip`, `cols_condense`, `parse_datetime`, `parse_factor`, `parse_guess`, `parse_logical`, `parse_number`, `parse_vector`

### Examples

    cols(a = col_integer())
    cols_only(a = col_integer())

    # You can also use the standard abbreviations
    cols(a = "i")
    cols(a = "i", b = "d", c = "_")

    # You can also use multiple sets of column definitions by combining
    # them like so:

    t1 <- cols(
      column_one = col_integer(),
      column_two = col_number())

    t2 <- cols(
     column_three = col_character())

    t3 <- t1
    t3$cols <- c(t1$cols, t2$cols)
    t3

[Package readr version 1.3.1 Index]