Added with_entries

pkg/yqlib/doc/Entries.md

@@ -1,4 +1,4 @@
-
+Similar to the same named functions in `jq` these functions convert to/from an object and an array of key-value pairs. This is most useful for performing operations on keys of maps.
 ## to_entries Map
 Given a sample.yml file of:
 ```yaml
@@ -69,3 +69,19 @@ will output
 1: b
 ```
 
+## Use with_entries to update keys
+Given a sample.yml file of:
+```yaml
+a: 1
+b: 2
+```
+then
+```bash
+yq eval 'with_entries(.key |= "KEY_" + .)' sample.yml
+```
+will output
+```yaml
+KEY_a: 1
+KEY_b: 2
+```
+

pkg/yqlib/doc/Traverse (Read).md

@@ -98,6 +98,23 @@ will output
 null
 ```
 
+## Optional identifier
+Like jq, does not output an error when the yaml is not an array or object as expected
+
+Given a sample.yml file of:
+```yaml
+- 1
+- 2
+- 3
+```
+then
+```bash
+yq eval '.a?' sample.yml
+```
+will output
+```yaml
+```
+
 ## Wildcard matching
 Given a sample.yml file of:
 ```yaml

pkg/yqlib/doc/headers/Entries.md

@@ -0,0 +1 @@
+Similar to the same named functions in `jq` these functions convert to/from an object and an array of key-value pairs. This is most useful for performing operations on keys of maps.