Different spacing while printing to log
<p>I am printing importance matrix of xgBoost into log using write command (write works with file connection and direct it to <code>stderr</code> well). Here is the command I am using:</p>

<pre><code>importance_matrix &lt;- xgb.importance(names, model=bst)
write("The top 30 variables are:",stderr())
write(paste0("Feature",'\t','\t','Gain','\t','Cover','\t','Frequency'),stderr())
write(t(as.matrix(importance_matrix[1:30,])),sep="\t",ncolumns = length(names(importance_matrix)),stderr())
</code></pre>

<p>Output comes in format: </p>

<pre><code>Feature         Gain    Cover   Frequency
pctTillDate 0.560359696 0.1314074664    0.024278250
colr_per    0.183149483 0.0962457545    0.049618673
date    0.050528297 0.1143752021    0.066395735
GREG_D  0.025648433 0.0381476142    0.018070143
LNGTD_I 0.020346020 0.0485235001    0.101322109
LATTD_I 0.019241497 0.0421892270    0.093867103
</code></pre>

<p>which make it look a bit clumsy (much clumsy in log than appearing here in SO). So in order to make it better looking I want to change last line of <code>t(as.matrix(importance_matrix[1:30,])),sep="\t"</code> such that first <code>sep</code> will be 2 tabs ('\t','\t') and rest single tab ('\t'); instead of current uniform spacing. Simple but search doesn't give any idea. Any suggestions?</p>