Array to map operator for #1415

pkg/yqlib/doc/operators/array-to-map.md

@@ -0,0 +1,28 @@
+# Array to Map
+
+Use this operator to convert an array to..a map. Skips over null values.
+
+Behind the scenes, this is implemented using reduce:
+
+```
+(.[] | select(. != null) ) as $i ireduce({}; .[$i | key] = $i)
+```
+
+## Simple example
+Given a sample.yml file of:
+```yaml
+cool:
+  - null
+  - null
+  - hello
+```
+then
+```bash
+yq '.cool |= array_to_map' sample.yml
+```
+will output
+```yaml
+cool:
+  2: hello
+```
+

pkg/yqlib/doc/operators/headers/array-to-map.md

@@ -0,0 +1,9 @@
+# Array to Map
+
+Use this operator to convert an array to..a map. Skips over null values.
+
+Behind the scenes, this is implemented using reduce:
+
+```
+(.[] | select(. != null) ) as $i ireduce({}; .[$i | key] = $i)
+```

pkg/yqlib/doc/usage/properties.md

@@ -149,6 +149,23 @@ person:
         - pizza
 ```
 
+## Decode properties - array should be a map
+If you have a numeric map key in your property files, use array_to_map to convert them to maps.
+
+Given a sample.properties file of:
+```properties
+things.10 = mike
+```
+then
+```bash
+yq -p=props '.things |= array_to_map' sample.properties
+```
+will output
+```yaml
+things:
+    10: mike
+```
+
 ## Roundtrip
 Given a sample.properties file of:
 ```properties