add nextflow d30e48d

nextflow/docs/snippets/first.nf

@@ -0,0 +1,19 @@
+// no condition is specified, emits the very first item: 1
+channel.of( 1, 2, 3 )
+    .first()
+    .view()
+
+// emits the first item matching the regular expression: 'aa'
+channel.of( 'a', 'aa', 'aaa' )
+    .first( ~/aa.*/ )
+    .view()
+
+// emits the first String value: 'a'
+channel.of( 1, 2, 'a', 'b', 3 )
+    .first( String )
+    .view()
+
+// emits the first item for which the predicate evaluates to true: 4
+channel.of( 1, 2, 3, 4, 5 )
+    .first { v -> v > 3 }
+    .view()