R: `ID : Coercing LHS to a list` in adding an ID column, why?
<p>I have data </p>

<pre><code>       N11.1 N22.2 N33.1 N44.1 N21.1 N31.1 N32.1
Sinus      1     0     0   0.0     0     0  12.0
ArrAHB     1     0     0   0.1     0     0  20.9
</code></pre>

<p>where I want to add an extra column <code>ID</code> with values <code>Sinus</code> and <code>ArrAHB</code>.</p>

<pre><code>require(lattice)
Sinus&lt;-c(1,0,0,0,0,0,12)
ArrAHB&lt;-c(1,0,0,0.1,0,0,20.9)
Labels&lt;-c("N11.1","N22.2","N33.1","N44.1","N21.1","N31.1","N32.1")
ID&lt;-c("Sinus","Arr/AHB")
data.female&lt;-data.frame(Sinus,ArrAHB,row.names=Labels)
data.female&lt;-t(data.female)

&gt; data.female$ID&lt;-ID

Warning message:
In data.female$ID &lt;- ID : Coercing LHS to a list
</code></pre>

<blockquote>
  <p><strong>Why does the creation of the ID column cause the coercion in the data.frame?</strong></p>
</blockquote>

<p><em>P.s. My goal is to get this data to the form like <a href="https://stackoverflow.com/a/22265066/164148">here</a> for <code>barchart(N11.1+N22.1+N33.1+N44.1+N21.1+N31.1+N32.1 ~ ID, data=data.female)</code> which requires a new ID column <a href="https://stackoverflow.com/q/40678499/164148">here</a>, I cannot understand why this ID addition sometimes works and sometimes not. Please explain.</em></p>