readr (version 0.1.0)

type_convert: Re-convert character columns in existing data frame.

Description

This is useful if you need to do some manual munging - you can read the columns in as character, clean it up with (e.g.) regular expressions and then let readr take another stab at parsing it.

Usage

type_convert(df, col_types = NULL)

Arguments

df

A data frame.

col_types

One of NULL, a list, a named list or a string.

If NULL, the column type will be imputed from the first 30 rows on the input. This is convenient (and fast), but not robust. If the imputation fails, you'll need to supply the correct types yourself.

If a list, it must contain one "collector" for each column. If you only want to read a subset of the columns, you can use a named list (where the names give the column names). If a column is not mentioned by name, it will not be included in the output.

Alternatively, you can use a compact string representation where each character represents one column: c = character, d = double, i = integer, l = logical and _ skips the column.

Examples

df <- data.frame(
  x = as.character(runif(10)),
  y = as.character(sample(10)),
  stringsAsFactors = FALSE
)
str(df)
str(type_convert(df))