Update 555-data-isarray.markdown

Author: Joe7M

_build/reference/555-data-isarray.markdown

@@ -1,7 +1,21 @@
 # ISARRAY
 
-> ISARRAY (x)
+> b = ISARRAY (x)
 
 Returns true if x is an array.
 
+### Example
 
+```
+A = [1,2,3]
+print IsArray(A)    ' Output 1
+
+A = {"x":1, "y":2}
+print IsArray(A)    ' Output 0 (is a map)
+
+A = 1
+print IsArray(A)    ' Output 0 (is a number)
+
+A = "abc"
+print IsArray(A)    ' Output 0 (is a string)
+```