readr (version 0.2.2)

count_fields: Count the number of fields in each line of a file.

Description

This is useful for diagnosing problems with functions that fail to parse correctly.

Usage

count_fields(file, tokenizer, skip = 0, n_max = -1L)

Arguments

file

Either a path to a file, a connection, or literal data (either a single string or a raw vector).

Files ending in .gz, .bz2, .xz, or .zip will be automatically uncompressed. Files starting with http://, https://, ftp://, or ftps:// will be automatically downloaded. Remote gz files can also be automatically downloaded & decompressed.

Literal data is most useful for examples and tests. It must contain at least one new line to be recognised as data (instead of a path).

tokenizer

A tokenizer that specifies how to break the file up into fields, e.g., tokenizer_csv, tokenizer_fwf

skip

Number of lines to skip before reading data.

n_max

Optionally, maximum number of rows to count fields for.

Examples

count_fields(system.file("extdata/mtcars.csv", package = "readr"),
 tokenizer_csv())