EVOLUTION-MANAGER

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

<h2>Roman Numerals</h2>

<h3>Description</h3>

<p>Simple manipulation of (a small set of) integer numbers as roman numerals.
</p>

<h3>Usage</h3>

<pre>
as.roman(x)
.romans

r1 + r2
r1 &lt;= r2
max(r1)
sum(r2)

</pre>

<h3>Arguments</h3>

<table summary="R argblock">
<tr valign="top"><td><code>x</code></td>
<td>
<p>a numeric or character vector of arabic or roman numerals.</p>
</td></tr>
<tr valign="top"><td><code>r1, r2</code></td>
<td>
<p>a roman number vector, i.e., of <code><a href="../../base/html/class.html">class</a></code>
<code>"roman"</code>.</p>
</td></tr>
</table>

<h3>Details</h3>

<p><code>as.roman</code> creates objects of class <code>"roman"</code> which are
internally represented as integers, and have suitable methods for
printing, formatting, subsetting, coercion, etc, see
<code><a href="methods.html">methods</a>(class = "roman")</code>.
</p>
<p>Arithmetic (<code>"<a href="../../methods/html/S4groupGeneric.html">Arith</a>"</code>), Comparison (<code>"<a href="../../methods/html/S4groupGeneric.html">Compare</a>"</code>)
and  (<code>"<a href="../../methods/html/S4groupGeneric.html">Logic</a>"</code>), i.e., all <code>"<a href="../../methods/html/S4groupGeneric.html">Ops</a>"</code> group
operations work as for regular numbers via <span style="font-family: Courier New, Courier; color: #666666;"><b>R</b></span>'s integer functionality.
</p>
<p>Only numbers between 1 and 3899 have a unique representation as roman
numbers, and hence others result in <code>as.roman(NA)</code>.
</p>
<p><code>.romans</code> is the basic dictionary, a named <code><a href="../../base/html/character.html">character</a></code> vector.
</p>

<h3>References</h3>

<p>Wikipedia contributors (2006). Roman numerals.
Wikipedia, The Free Encyclopedia.
<a href="https://en.wikipedia.org/w/index.php?title=Roman_numerals&amp;oldid=78252134">https://en.wikipedia.org/w/index.php?title=Roman_numerals&amp;oldid=78252134</a>.
Accessed September 29, 2006.
</p>

<h3>Examples</h3>

<pre>
## First five roman 'numbers'.
(y &lt;- as.roman(1 : 5))
## Middle one.
y[3]
## Current year as a roman number.
(y &lt;- as.roman(format(Sys.Date(), "%Y")))
## Today, and  10, 20, 30, and 100 years ago ...
y - 10*c(0:3,10)

## mixture of arabic and roman numbers :
as.roman(c(NA, 1:3, "", strrep("I", 1:6))) # + NA with a warning for "IIIIII"
cc &lt;- c(NA, 1:3, strrep("I", 0:5))
(rc &lt;- as.roman(cc)) # two NAs: 0 is not "roman"
(ic &lt;- as.integer(rc)) # works automatically [without an explicit method]
rNA &lt;- as.roman(NA)
## simple consistency checks -- arithmetic when result is in  {1,2,..,3899} :
stopifnot(identical(rc, as.roman(rc)), # as.roman(.) is "idempotent"
          identical(rc + rc + (3*rc), rc*5),
          identical(ic, c(NA, 1:3, NA, 1:5)),
          identical(as.integer(5*rc), 5L*ic),
          identical(as.numeric(rc), as.numeric(ic)),
          identical(rc[1], rNA),
          identical(as.roman(0), rNA),
          identical(as.roman(NA_character_), rNA),
          identical(as.list(rc), as.list(ic)))
## Non-Arithmetic 'Ops' :
stopifnot(exprs = {
        # Comparisons :
        identical(ic &lt; 1:5, rc &lt; 1:5)
        identical(ic &lt; 1:5, rc &lt; as.roman(1:5))
        # Logic  [integers |-&gt; logical] :
        identical(rc &amp; TRUE , ic &amp; TRUE)
        identical(rc &amp; FALSE, ic &amp; FALSE)
        identical(rc | FALSE, ic | FALSE)
        identical(rc | NA   , ic | NA)
})
## 'Summary' group functions (and comparison):
(rc. &lt;- rc[!is.na(rc)])
stopifnot(exprs = {
        identical(min(rc), as.roman(NA))
        identical(min(rc, na.rm=TRUE),
         as.roman(min(ic, na.rm=TRUE)))
        identical(range(rc.),
         as.roman(range(as.integer(rc.))))
        identical(sum (rc, na.rm=TRUE), as.roman("XXI"))
        identical(format(prod(rc, na.rm=TRUE)), "DCCXX")
        format(prod(rc.)) == "DCCXX"
})
</pre>

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