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Edit File: melt_fwf.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><title>R: Return melted data for each token in a fixed width file</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link rel="stylesheet" type="text/css" href="R.css" /> </head><body> <table width="100%" summary="page for melt_fwf {readr}"><tr><td>melt_fwf {readr}</td><td style="text-align: right;">R Documentation</td></tr></table> <h2>Return melted data for each token in a fixed width file</h2> <h3>Description</h3> <p>For certain non-rectangular data formats, it can be useful to parse the data into a melted format where each row represents a single token. </p> <h3>Usage</h3> <pre> melt_fwf(file, col_positions, locale = default_locale(), na = c("", "NA"), comment = "", trim_ws = TRUE, skip = 0, n_max = Inf, progress = show_progress(), skip_empty_rows = FALSE) </pre> <h3>Arguments</h3> <table summary="R argblock"> <tr valign="top"><td><code>file</code></td> <td> <p>Either a path to a file, a connection, or literal data (either a single string or a raw vector). </p> <p>Files ending in <code>.gz</code>, <code>.bz2</code>, <code>.xz</code>, or <code>.zip</code> will be automatically uncompressed. Files starting with <code>http://</code>, <code>https://</code>, <code>ftp://</code>, or <code>ftps://</code> will be automatically downloaded. Remote gz files can also be automatically downloaded and decompressed. </p> <p>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) or be a vector of greater than length 1. </p> <p>Using a value of <code><a href="clipboard.html">clipboard()</a></code> will read from the system clipboard.</p> </td></tr> <tr valign="top"><td><code>col_positions</code></td> <td> <p>Column positions, as created by <code><a href="read_fwf.html">fwf_empty()</a></code>, <code><a href="read_fwf.html">fwf_widths()</a></code> or <code><a href="read_fwf.html">fwf_positions()</a></code>. To read in only selected fields, use <code><a href="read_fwf.html">fwf_positions()</a></code>. If the width of the last column is variable (a ragged fwf file), supply the last end position as NA.</p> </td></tr> <tr valign="top"><td><code>locale</code></td> <td> <p>The locale controls defaults that vary from place to place. The default locale is US-centric (like R), but you can use <code><a href="locale.html">locale()</a></code> to create your own locale that controls things like the default time zone, encoding, decimal mark, big mark, and day/month names.</p> </td></tr> <tr valign="top"><td><code>na</code></td> <td> <p>Character vector of strings to interpret as missing values. Set this option to <code>character()</code> to indicate no missing values.</p> </td></tr> <tr valign="top"><td><code>comment</code></td> <td> <p>A string used to identify comments. Any text after the comment characters will be silently ignored.</p> </td></tr> <tr valign="top"><td><code>trim_ws</code></td> <td> <p>Should leading and trailing whitespace be trimmed from each field before parsing it?</p> </td></tr> <tr valign="top"><td><code>skip</code></td> <td> <p>Number of lines to skip before reading data.</p> </td></tr> <tr valign="top"><td><code>n_max</code></td> <td> <p>Maximum number of records to read.</p> </td></tr> <tr valign="top"><td><code>progress</code></td> <td> <p>Display a progress bar? By default it will only display in an interactive session and not while knitting a document. The display is updated every 50,000 values and will only display if estimated reading time is 5 seconds or more. The automatic progress bar can be disabled by setting option <code>readr.show_progress</code> to <code>FALSE</code>.</p> </td></tr> <tr valign="top"><td><code>skip_empty_rows</code></td> <td> <p>Should blank rows be ignored altogether? i.e. If this option is <code>TRUE</code> then blank rows will not be represented at all. If it is <code>FALSE</code> then they will be represented by <code>NA</code> values in all the columns.</p> </td></tr> </table> <h3>Details</h3> <p><code>melt_fwf()</code> parses each token of a fixed width file into a single row, but it still requires that each field is in the same in every row of the source file. </p> <h3>See Also</h3> <p><code><a href="melt_table.html">melt_table()</a></code> to melt fixed width files where each column is separated by whitespace, and <code><a href="read_fwf.html">read_fwf()</a></code> for the conventional way to read rectangular data from fixed width files. </p> <h3>Examples</h3> <pre> fwf_sample <- readr_example("fwf-sample.txt") cat(read_lines(fwf_sample)) # You can specify column positions in several ways: # 1. Guess based on position of empty columns melt_fwf(fwf_sample, fwf_empty(fwf_sample, col_names = c("first", "last", "state", "ssn"))) # 2. A vector of field widths melt_fwf(fwf_sample, fwf_widths(c(20, 10, 12), c("name", "state", "ssn"))) # 3. Paired vectors of start and end positions melt_fwf(fwf_sample, fwf_positions(c(1, 30), c(10, 42), c("name", "ssn"))) # 4. Named arguments with start and end positions melt_fwf(fwf_sample, fwf_cols(name = c(1, 10), ssn = c(30, 42))) # 5. Named arguments with column widths melt_fwf(fwf_sample, fwf_cols(name = 20, state = 10, ssn = 12)) </pre> <hr /><div style="text-align: center;">[Package <em>readr</em> version 1.3.1 <a href="00Index.html">Index</a>]</div> </body></html>