| bytes | Package bytes implements functions for the manipulation of byte slices. |
| io | Package io provides basic interfaces to I/O primitives. |
| net/url | Package url parses URLs and implements query escaping. |
| regexp | Package regexp implements regular expression search. |
| sort | Package sort provides primitives for sorting slices and user-defined collections. |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |
| unicode/utf8 | Package utf8 implements functions and constants to support text encoded in UTF-8. |