Sorted Sets

In [20]: r.z
r.zadd              r.zincrby           r.zrange            r.zrank             r.zremrangebyrank   r.zrevrangebyscore  r.zscan_iter
r.zcard             r.zinterstore       r.zrangebylex       r.zrem              r.zremrangebyscore  r.zrevrank          r.zscore
r.zcount            r.zlexcount         r.zrangebyscore     r.zremrangebylex    r.zrevrange         r.zscan             r.zunionstore

Tips: score from Redis will be float even though set int
Tips: Descending lexicographical order is used for elements with equal score.

Insert

Add Element Into Sorted Set
```
zadd(name, *args, **kwargs)
```
Set any number of score, element-name pairs to the key name. Pairs can be specified in two ways:

As args, in the form of: score1, name1, score2, name2, ... or as *kwargs, in the form of: name1=score1, name2=score2, ...

The following example would add four values to the ‘my-key’ key: redis.zadd(‘my-key’, 1.1, ‘name1’, 2.2, ‘name2’, name3=3.3, name4=4.4)
```
In [51]: r.zadd('sorted_set', 1, 'a')
Out[51]: 1

In [52]: r.zadd('sorted_set', 2, 'b', 3, 'c')
Out[52]: 2

In [53]: r.zadd('sorted_set', **{'d': 4})
Out[53]: 1

In [54]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[54]: [('a', 1.0), ('b', 2.0), ('c', 3.0), ('d', 4.0)]
```
Tips: Some Redis Version, Can Just Add One Element One Time

Select

Select Elements By Index
- Sorted In Ascending Order
```
zrange(name, start, end, desc=False, withscores=False, score_cast_func=<type 'float'>)
```
  Return a range of values from sorted set name between start and end sorted in ascending order.
  
  start and end can be negative, indicating the end of the range.
  
  desc a boolean indicating whether to sort the results descendingly.
  
  withscores indicates to return the scores along with the values. The return type is a list of (value, score) pairs.
  
  score_cast_func a callable used to cast the score return value.
```
In [65]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[65]: [('a', 1.0), ('b', 2.0), ('c', 3.0), ('d', 4.0)]

In [66]: r.zrange('sorted_set', 0, 100, desc=True, withscores=True)
Out[66]: [('d', 4.0), ('c', 3.0), ('b', 2.0), ('a', 1.0)]
```
- Sorted In Descending Order
```
zrevrange(name, start, end, withscores=False, score_cast_func=<type 'float'>)
```
  Return a range of values from sorted set name between start and end sorted in descending order.
  
  start and end can be negative, indicating the end of the range.
  
  withscores indicates to return the scores along with the values. The return type is a list of (value, score) pairs.
  
  score_cast_func a callable used to cast the score return value.
```
In [7]: r.zrevrange('sorted_set', 0, 100, withscores=True)
Out[7]: [('d', 4.0), ('c', 3.0), ('b', 2.0), ('a', 1.0)]
```
  Tips: zrange desc equals zrevrange
Select Elements By Score
- Sorted In Ascending Order
```
zrangebyscore(name, min, max, start=None, num=None, withscores=False, score_cast_func=<type 'float'>)
```
  Return a range of values from the sorted set name with scores between min and max.
  
  If start and num are specified, then return a slice of the range.
  
  withscores indicates to return the scores along with the values. The return type is a list of (value, score) pairs.
  
  score_cast_func` a callable used to cast the score return value.
```
In [13]: r.zrangebyscore('sorted_set', 0, 100, start=0, num=1, withscores=True)
Out[13]: [('a', 1.0)]
```
- Sorted In Descending Order
```
zrevrangebyscore(name, max, min, start=None, num=None, withscores=False, score_cast_func=<type 'float'>)
```
  Return a range of values from the sorted set name with scores between min and max in descending order.
  
  If start and num are specified, then return a slice of the range.
  
  withscores indicates to return the scores along with the values. The return type is a list of (value, score) pairs.
  
  score_cast_func a callable used to cast the score return value.
```
In [19]: r.zrevrangebyscore('sorted_set', 100, 0, start=0, num=1, withscores=True)
Out[19]: [('d', 4.0)]
```

Select Elements By Alphabet
- Sorted In Ascending Order
```
zrangebylex(name, min, max, start=None, num=None)
```
  Return the lexicographical range of values from sorted set name between min and max. If start and num are specified, then return a slice of the range.
```
In [72]: r.zrangebylex('sorted_set', '[a', '(b')
Out[72]: ['a']

In [73]: r.zrangebylex('sorted_set', '[a', '[b')
Out[73]: ['a', 'b']
```
- Sorted In Descending Order
```
zrevrangebylex(name, max, min, start=None, num=None)
```
  Return the reversed lexicographical range of values from sorted set name between max and min. If start and num are specified, then return a slice of the range.
Count Elements
- All (-∞ < score < ∞)
```
zcard(name)
```
  Return the number of elements in the sorted set name
```
In [48]: r.zcard('sorted_set')
Out[48]: 4
```
- Score (min <= score <= max)
```
zcount(name, min, max)
```
  Returns the number of elements in the sorted set at key name with a score between min and max.
```
In [26]: r.zcount('sorted_set', 0, 100)
Out[26]: 4L
```
- Alphabet (alphabet between min and max)
```
zlexcount(name, min, max)
```
  Return the number of items in the sorted set name between the lexicographical range min and max.

Get Element's Score

zscore(name, value)

Return the score of element value in sorted set name

In [29]: r.zscore('sorted_set', 'd')
Out[29]: 4.0

Get Element's Rank Index

Sorted In Ascending Order

zrank(name, value)

Returns a 0-based value indicating the rank of value in sorted set name

In [40]: r.zrank('sorted_set', 'a')
Out[40]: 0

In [41]: r.zrank('sorted_set', 'd')
Out[41]: 3

Sorted In Descending Order

zrevrank(name, value)

Returns a 0-based value indicating the descending rank of value in sorted set name

In [43]: r.zrevrank('sorted_set', 'a')
Out[43]: 3

In [44]: r.zrevrank('sorted_set', 'd')
Out[44]: 0

Update

Increase Element's Score

zincrby(name, value, amount=1)

Increment the score of value in sorted set name by amount

In [50]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[50]: [('a', 1.0), ('b', 2.0), ('c', 3.0), ('d', 4.0)]

In [51]: r.zincrby('sorted_set', 'e', 5)
Out[51]: 5.0

In [52]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[52]: [('a', 1.0), ('b', 2.0), ('c', 3.0), ('d', 4.0), ('e', 5.0)]

In [53]: r.zincrby('sorted_set', 'e', 5)
Out[53]: 10.0

In [54]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[54]: [('a', 1.0), ('b', 2.0), ('c', 3.0), ('d', 4.0), ('e', 10.0)]

Delete

Delete Elements By Element

zrem(name, *values)

Remove member values from sorted set name

In [54]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[54]: [('a', 1.0), ('b', 2.0), ('c', 3.0), ('d', 4.0), ('e', 10.0)]

In [55]: r.zrem('sorted_set', 'e')
Out[55]: 1

In [56]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[56]: [('a', 1.0), ('b', 2.0), ('c', 3.0), ('d', 4.0)]

Delete Elements By Index

zremrangebyrank(name, min, max)

Remove all elements in the sorted set name with ranks between min and max. Values are 0-based, ordered from smallest score to largest. Values can be negative indicating the highest scores. Returns the number of elements removed

In [60]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[60]: [('a', 1.0), ('b', 2.0), ('c', 3.0), ('d', 4.0)]

In [61]: r.zremrangebyrank('sorted_set', 2, -1)
Out[61]: 2

In [62]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[62]: [('a', 1.0), ('b', 2.0)]

Delete Elements By Score

zremrangebyscore(name, min, max)

Remove all elements in the sorted set name with scores between min and max. Returns the number of elements removed.

In [62]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[62]: [('a', 1.0), ('b', 2.0)]

In [63]: r.zremrangebyscore('sorted_set', 0, 100)
Out[63]: 2

In [64]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[64]: []

Delete Elements By Alphabet

zremrangebylex(name, min, max)

Remove all elements in the sorted set name between the lexicographical range specified by min and max. Returns the number of elements removed.

In [77]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[77]: [('a', 1.0), ('b', 2.0), ('c', 3.0), ('d', 4.0)]

In [78]: r.zremrangebylex('sorted_set', '[a', '[b')
Out[78]: 2

In [79]: r.zrange('sorted_set', 0, 100, withscores=True)
Out[79]: [('c', 3.0), ('d', 4.0)]

Other

Intersect
```
zinterstore(dest, keys, aggregate=None)
```
Intersect multiple sorted sets specified by keys into a new sorted set, dest. Scores in the destination will be aggregated based on the aggregate, or SUM if none is provided.
Union
```
zunionstore(dest, keys, aggregate=None)
```
Union multiple sorted sets specified by keys into a new sorted set, dest. Scores in the destination will be aggregated based on the aggregate, or SUM if none is provided.

Param

score_cast_func

In [10]: def score_cast_func(score):
   ...:     return int(score) ** 2
   ...:

In [11]: r.zrange('sorted_set', 0, 100, desc=True, withscores=True)
Out[11]: [('d', 4.0), ('c', 3.0), ('b', 2.0), ('a', 1.0)]

In [12]: r.zrange('sorted_set', 0, 100, desc=True, withscores=True, score_cast_func=score_cast_func)
Out[12]: [('d', 16), ('c', 9), ('b', 4), ('a', 1)]

Usage

Select Top N

# TOP 100
In [55]: r.zrange('sorted_set', 0, 100-1, desc=True, withscores=True)
Out[55]: [('d', 4.0), ('c', 3.0), ('b', 2.0), ('a', 1.0)]

In [56]: r.zrevrange('sorted_set', 0, 100-1, withscores=True)
Out[56]: [('d', 4.0), ('c', 3.0), ('b', 2.0), ('a', 1.0)]

# In [56]: r.zrevrange('sorted_set', 0, N-1, withscores=True)

Sorted By Timestamp When Score Equals
- Solution1 — Score Transform
  - Magic Usages In Action — Sorted Set
- Solution2 — zinterstore
  - If what you want is not just sorted by timestamp, this solution is perfect
  - Liu Wei@Redis DB@GoogleGroups — redis sorted set order by multi scores
  - Blog@dr-josiah — Multi-column (SQL-like) sorting in Redis
  - josiahcarlson/sort_zset_cols.py — A method to get sql-like multiple-column order by in Redis
- Solution3 — Name Transform
  - Bruce Dou@StackOverflow — Redis: Is it possible sort ordered set result with same score by other key value

References

[1] redis-py@Github, redis-py

[2] redis-py@ReadTheDocs, redis-py’s documentation

Sorted Sets

Sorted Sets

Insert

Select

Update

Delete

Other

Param

Usage

References

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