math.extras: adding nonzero.

slavapestov · Jun 19, 2012 · 3006999 · 3006999
1 parent 023898f
commit 3006999
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diff --git a/extra/math/extras/extras-tests.factor b/extra/math/extras/extras-tests.factor
@@ -20,3 +20,6 @@ IN: math.extras.test
 [ 10 [1,b] 2 exponential-moving-average ] unit-test
 
 { { 2 5 5 4 3 } } [ { 1 2 5 6 1 4 3 } 3 moving-median ] unit-test
+
+{ { } } [ { 0 0 } nonzero ] unit-test
+{ { 1 2 3 } } [ { 0 1 0 2 0 3 0 } nonzero ] unit-test
diff --git a/extra/math/extras/extras.factor b/extra/math/extras/extras.factor
@@ -94,3 +94,6 @@ PRIVATE>
 
 : moving-median ( u n -- v )
     <clumps> [ median ] map ;
+
+: nonzero ( seq -- seq' )
+    [ zero? not ] filter ;