read_fwf {readr} | R Documentation |
A fixed width file can be a very compact representation of numeric data. It's also very fast to parse, because every field is in the same place in every line. Unfortunately, it's painful to parse because you need to describe the length of every field. Readr aims to make it as easy as possible by providing a number of different ways to describe the field structure.
read_fwf(file, col_positions, col_types = NULL, locale = default_locale(), na = c("", "NA"), comment = "", skip = 0, n_max = Inf, guess_max = min(n_max, 1000), progress = interactive()) fwf_empty(file, skip = 0, col_names = NULL, comment = "") fwf_widths(widths, col_names = NULL) fwf_positions(start, end, col_names = NULL)
file |
Either a path to a file, a connection, or literal data (either a single string or a raw vector). Files ending in 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). |
col_positions |
Column positions, as created by |
col_types |
One of If If a column specification created by Alternatively, you can use a compact string representation where each
character represents one column:
c = character, i = integer, n = number, d = double,
l = logical, D = date, T = date time, t = time, ? = guess, or
|
locale |
The locale controls defaults that vary from place to place.
The default locale is US-centric (like R), but you can use
|
na |
Character vector of strings to use for missing values. Set this
option to |
comment |
A string used to identify comments. Any text after the comment characters will be silently ignored. |
skip |
Number of lines to skip before reading data. |
n_max |
Maximum number of records to read. |
guess_max |
Maximum number of records to use for guessing column types. |
progress |
Display a progress bar? By default it will only display in an interactive session. The display is updated every 50,000 values and will only display if estimated reading time is 5 seconds or more. |
col_names |
Either NULL, or a character vector column names. |
widths |
Width of each field. Use NA as width of last field when reading a ragged fwf file. |
start, end |
Starting and ending (inclusive) positions of each field. Use NA as last end field when reading a ragged fwf file. |
read_table
to read fixed width files where each
column is separated by whitespace.
fwf_sample <- readr_example("fwf-sample.txt") cat(read_lines(fwf_sample)) # You can specify column positions in three ways: # 1. Guess based on position of empty columns read_fwf(fwf_sample, fwf_empty(fwf_sample, col_names = c("first", "last", "state", "ssn"))) # 2. A vector of field widths read_fwf(fwf_sample, fwf_widths(c(20, 10, 12), c("name", "state", "ssn"))) # 3. Paired vectors of start and end positions read_fwf(fwf_sample, fwf_positions(c(1, 30), c(10, 42), c("name", "ssn")))