R: Fast data frame input

read.csv.raw {iotools}

R Documentation

Fast data frame input

Description

A fast replacement of read.csv and read.delim which pre-loads the data as a raw vector and parses without constructing intermediate strings.

Usage

read.csv.raw(file, header=TRUE, sep=",", skip=0L, fileEncoding="",
              colClasses, nrows = -1L, nsep = NA, strict=TRUE,
              nrowsClasses = 25L, quote="'\"")

read.delim.raw(file, header=TRUE, sep="\t", ...)

Arguments

`file`	A connection object or a character string naming a file from which to read data.
`header`	logical. Does a header row exist for the data.
`sep`	single character: field (column) separator.
`skip`	integer. Number of lines to skip in the input, no including the header.
`fileEncoding`	The name of the encoding to be assumed. Only used when `con` is a character string naming a file.
`colClasses`	an optional character vector indicating the column types. A vector of classes to be assumed for the output dataframe. If it is a list, `class(x)[1]` will be used to determine the class of the contained element. It will not be recycled, and must be at least as long as the longest row if `strict` is `TRUE`. Possible values are `"NULL"` (when the column is skipped) one of the six atomic vector types (`'character'`, `'numeric'`, `'logical'`, `'integer'`, `'complex'`, `'raw'`) or `POSIXct`. 'POSIXct' will parse date format in the form "YYYY-MM-DD hh:mm:ss.sss" assuming GMT time zone. The separators between digits can be any non-digit characters and only the date part is mandatory. See also `fasttime::asPOSIXct` for details.
`nrows`	integer: the maximum number of rows to read in. Negative and other invalid values are ignored.
`nsep`	index name separator (single character) or `NA` if no index names are included
`strict`	logical, if `FALSE` then `dstrsplit` will not fail on parsing errors, otherwise input not matching the format (e.g. more columns than expected) will cause an error.
`nrowsClasses`	integer. Maximum number of rows of data to read to learn column types. Not used when `col_types` is supplied.
`quote`	the set of quoting characters as a length 1 vector. To disable quoting altogether, use `quote = ""`. Quoting is only considered for columns read as character.
`...`	additional parameters to pass to `read.csv.raw`

Details

See dstrsplit for the details of nsep, sep, and strict.

Value

A data frame containing a representation of the data in the file.

Author(s)

Taylor Arnold and Simon Urbanek

[Package iotools version 0.3-3 Index]