[bugfix] Fix percent metric display and check for string columns in t…

…able (apache#5917)

* fix percent metric display

* add empty line

* address string or number check

superset/assets/src/visualizations/table.js

@@ -46,6 +46,7 @@ const propTypes = {
 };
 
 const formatValue = d3.format('0,000');
+const formatPercent = d3.format('.3p');
 function NOOP() {}
 
 function TableVis(element, props) {
@@ -76,7 +77,7 @@ function TableVis(element, props) {
     // Add percent metrics
     .concat((percentMetrics || []).map(m => '%' + m))
     // Removing metrics (aggregates) that are strings
-    .filter(m => !Number.isNaN(data[0][m]));
+    .filter(m => (typeof data[0][m]) === 'number');
 
   function col(c) {
     const arr = [];
@@ -131,9 +132,11 @@ function TableVis(element, props) {
       }
       if (isMetric) {
         html = d3.format(format || '0.3s')(val);
-      } else if (key[0] === '%') {
-        html = d3.format('.3p')(val);
       }
+      if (key[0] === '%') {
+        html = formatPercent(val);
+      }
+
       return {
         col: key,
         val,