GitBook: [#206] deep update example

operators/select.md

@@ -0,0 +1,52 @@
+# Select
+
+Select is used to filter arrays and maps by a boolean expression.
+
+## Select elements from array
+
+Given a sample.yml file of:
+
+```yaml
+- cat
+- goat
+- dog
+```
+
+then
+
+```bash
+yq eval '.[] | select(. == "*at")' sample.yml
+```
+
+will output
+
+```yaml
+cat
+goat
+```
+
+## Select and update matching values in map
+
+Given a sample.yml file of:
+
+```yaml
+a:
+  things: cat
+  bob: goat
+  horse: dog
+```
+
+then
+
+```bash
+yq eval '(.a.[] | select(. == "*at")) |= "rabbit"' sample.yml
+```
+
+will output
+
+```yaml
+a:
+  things: rabbit
+  bob: rabbit
+  horse: dog
+```