--- a/qiime2/qiime_diversity_beta-rarefaction.xml	Mon Aug 05 01:29:30 2019 -0400
+++ b/qiime2/qiime_diversity_beta-rarefaction.xml	Tue Aug 13 07:46:48 2019 -0400
@@ -8,15 +8,20 @@
 qiime diversity beta-rarefaction
 
 --i-table=$itable
+
 --p-metric=$pmetric
+
 --p-clustering-method=$pclusteringmethod
---p-sampling-depth="$psamplingdepth"
+
+#if str($psamplingdepth):
+ --p-sampling-depth="$psamplingdepth"
+#end if
 
 #if str($iphylogeny) != 'None':
  --i-phylogeny=$iphylogeny
 #end if
 
-#if $piterations:
+#if str($piterations):
  --p-iterations=$piterations
 #end if