Add record to table example (nushell#370)

book/types_of_data.md

@@ -193,6 +193,17 @@ Records hold key-value pairs, much like objects in JSON. As these can sometimes
 ╰──────┴─────╯
 ```
 
+You can iterate over records by first transposing it into a table:
+```
+> echo {name: sam, rank: 10} | transpose key value
+╭───┬──────┬───────╮
+│ # │ key │ value │
+├───┼──────┼───────┤
+│ 0 │ name │ sam │
+│ 1 │ rank │ 10 │
+╰───┴──────┴───────╯
+```
+
 ## Lists
 
 Lists can hold more than one value. These can be simple values. They can also hold rows, and the combination of a list of records is often called a "table".