Understanding Redict Data Types #

Redict is a data structure server. At its core, Redict provides a collection of native data types that help you solve a wide variety of problems, from queuing to event processing. Below is a short description of each data type, with links to broader overviews and command references.

If you’d like to try a comprehensive tutorial for each data structure, see their overview pages below.

Core #

Strings #

Redict strings are the most basic Redict data type, representing a sequence of bytes. For more information, see:

• Overview of Redict strings
• Redict string command reference

Lists #

Redict lists are lists of strings sorted by insertion order. For more information, see:

• Overview of Redict lists
• Redict list command reference

Sets #

Redict sets are unordered collections of unique strings that act like the sets from your favorite programming language (for example, Java HashSets, Python sets, and so on). With a Redict set, you can add, remove, and test for existence in O(1) time (in other words, regardless of the number of set elements). For more information, see:

• Overview of Redict sets
• Redict set command reference

Hashes #

Redict hashes are record types modeled as collections of field-value pairs. As such, Redict hashes resemble Python dictionaries, Java HashMaps, and Ruby hashes. For more information, see:

• Overview of Redict hashes
• Redict hashes command reference

Sorted sets #

Redict sorted sets are collections of unique strings that maintain order by each string’s associated score. For more information, see:

• Overview of Redict sorted sets
• Redict sorted set command reference

Streams #

A Redict stream is a data structure that acts like an append-only log. Streams help record events in the order they occur and then syndicate them for processing. For more information, see:

• Overview of Redict Streams
• Redict Streams command reference

Geospatial indexes #

Redict geospatial indexes are useful for finding locations within a given geographic radius or bounding box. For more information, see:

• Overview of Redict geospatial indexes
• Redict geospatial indexes command reference

Bitmaps #

Redict bitmaps let you perform bitwise operations on strings. For more information, see:

• Overview of Redict bitmaps
• Redict bitmap command reference

Bitfields #

Redict bitfields efficiently encode multiple counters in a string value. Bitfields provide atomic get, set, and increment operations and support different overflow policies. For more information, see:

• Overview of Redict bitfields
• The BITFIELD command

HyperLogLog #

The Redict HyperLogLog data structures provide probabilistic estimates of the cardinality (i.e., number of elements) of large sets. For more information, see:

• Overview of Redict HyperLogLog
• Redict HyperLogLog command reference