EVOLUTION-MANAGER

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<table width="100%" summary="page for chartr {base}"><tr><td>chartr {base}</td><td style="text-align: right;">R Documentation</td></tr></table>

<h2>Character Translation and Casefolding</h2>

<h3>Description</h3>

<p>Translate characters in character vectors, in particular from upper to
lower case or vice versa.
</p>

<h3>Usage</h3>

<pre>
chartr(old, new, x)
tolower(x)
toupper(x)
casefold(x, upper = FALSE)
</pre>

<h3>Arguments</h3>

<table summary="R argblock">
<tr valign="top"><td><code>x</code></td>
<td>
<p>a character vector, or an object that can be coerced to
character by <code><a href="character.html">as.character</a></code>.</p>
</td></tr>
<tr valign="top"><td><code>old</code></td>
<td>
<p>a character string specifying the characters to be
translated.  If a character vector of length 2 or more is supplied,
the first element is used with a warning.</p>
</td></tr>
<tr valign="top"><td><code>new</code></td>
<td>
<p>a character string specifying the translations. If a
character vector of length 2 or more is supplied, the first element
is used with a warning.</p>
</td></tr>
<tr valign="top"><td><code>upper</code></td>
<td>
<p>logical: translate to upper or lower case?.</p>
</td></tr>
</table>

<h3>Details</h3>

<p><code>chartr</code> translates each character in <code>x</code> that is specified
in <code>old</code> to the corresponding character specified in <code>new</code>.
Ranges are supported in the specifications, but character classes and
repeated characters are not.  If <code>old</code> contains more characters
than new, an error is signaled; if it contains fewer characters, the
extra characters at the end of <code>new</code> are ignored.
</p>
<p><code>tolower</code> and <code>toupper</code> convert upper-case characters in a
character vector to lower-case, or vice versa.  Non-alphabetic
characters are left unchanged.
</p>
<p><code>casefold</code> is a wrapper for <code>tolower</code> and <code>toupper</code>
provided for compatibility with S-PLUS.
</p>

<h3>Value</h3>

<p>A character vector of the same length and with the same attributes as
<code>x</code> (after possible coercion).
</p>
<p>Elements of the result will be have the encoding declared as that of
the current locale (see <code><a href="Encoding.html">Encoding</a></code>) if the corresponding
input had a declared encoding and the current locale is either Latin-1
or UTF-8.  The result will be in the current locale's encoding unless
the corresponding input was in UTF-8, when it will be in UTF-8 when
the system has Unicode wide characters.
</p>

<p><code><a href="grep.html">sub</a></code> and <code><a href="grep.html">gsub</a></code> for other
substitutions in strings.
</p>

<h3>Examples</h3>

<pre>
x &lt;- "MiXeD cAsE 123"
chartr("iXs", "why", x)
chartr("a-cX", "D-Fw", x)
tolower(x)
toupper(x)

## "Mixed Case" Capitalizing - toupper( every first letter of a word ) :

.simpleCap &lt;- function(x) {
    s &lt;- strsplit(x, " ")[[1]]
    paste(toupper(substring(s, 1, 1)), substring(s, 2),
          sep = "", collapse = " ")
}
.simpleCap("the quick red fox jumps over the lazy brown dog")
## -&gt;  [1] "The Quick Red Fox Jumps Over The Lazy Brown Dog"

## and the better, more sophisticated version:
capwords &lt;- function(s, strict = FALSE) {
    cap &lt;- function(s) paste(toupper(substring(s, 1, 1)),
                  {s &lt;- substring(s, 2); if(strict) tolower(s) else s},
                             sep = "", collapse = " " )
    sapply(strsplit(s, split = " "), cap, USE.NAMES = !is.null(names(s)))
}
capwords(c("using AIC for model selection"))
## -&gt;  [1] "Using AIC For Model Selection"
capwords(c("using AIC", "for MODEL selection"), strict = TRUE)
## -&gt;  [1] "Using Aic"  "For Model Selection"
##                ^^^        ^^^^^
##               'bad'       'good'

## -- Very simple insecure crypto --
rot &lt;- function(ch, k = 13) {
   p0 &lt;- function(...) paste(c(...), collapse = "")
   A &lt;- c(letters, LETTERS, " '")
   I &lt;- seq_len(k); chartr(p0(A), p0(c(A[-I], A[I])), ch)
}

pw &lt;- "my secret pass phrase"
(crypw &lt;- rot(pw, 13)) #-&gt; you can send this off

## now ``decrypt'' :
rot(crypw, 54 - 13) # -&gt; the original:
stopifnot(identical(pw, rot(crypw, 54 - 13)))
</pre>

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