博客
关于我
pandas.groupby().rank()用法详解
阅读量:344 次
发布时间:2019-03-04

本文共 2774 字,大约阅读时间需要 9 分钟。

  • pandas.DataFrame.groupby()

Group DataFrame using a mapper or by a Series of columns.

A groupby operation involves some combination of splitting the object, applying a function, and combining the results. This can be used to group large amounts of data and compute operations on these groups.

  • Parameters
  1. by : mapping, function, label, or list of labes

    Used to determine the groups for the groupby.

    If by is a function, it’s called on each value of the object’s index.

    If a dict or Series is passed, the Series or dict VALUES will be used to determine the groups.

    If an ndarray is passed, the values are used as-is determine the groups.

    A label or list of labels may be passed to group by the columns in self.

  2. axis : {0 or ‘index’, 1 or ‘columns’}, default 0

    Split along rows (0) or columns (1).

  3. level : int, level name, or sequence of such, default None

    If the axis is a MultiIndex (hierarchical), group by a particular level or levels.

  4. as_index : bool, default True

    For aggregated output, return object with group labels. Only relevant for DataFrame input. as_index=False is effectively ‘SQL-style’ grouped output.

  5. sort : bool, default True

    Sort group keys.

    Get better performance by turning this off. Note this does not influence the order of observations within each group.

    Groupby preserves the order of rows within each group.

  6. group_keys : bool, default True

    When calling apply, add group keys to index to identify pieces.

  7. squeeze : bool, default True

    Reduce the dimensionality of the return type if possible, otherwise return a consistent type.

  8. observed : bool, default False

    This only applies if any of the groupers are Categoricals.

    If True : only show observed values for categorical groupers.

    If False : show all values for categorical groupers.

  9. dropna : bool, default True

    If True, and if group keys contain NA values, NA values together with row/column will be dropped.

    If False, NA values will also be treated as the key in groups.

  • Returns

Returns a groupby object that contains information about the groups.

  • PANDAS.DATAFRAME.RANK

DataFrame.rank(axis=0, method='average', numeric_only=None, na_option='keep', ascending=True,pct=False)

Computing numerical data ranks (1 through n) along axis.

By default, equal values are assigned a rank that is the average of the ranks of those values.

method : {‘average’, ‘min’, ‘max’, ‘first’, ‘dense’}, default ‘average’

How to rank the group of records that have the same value.

  1. average : average rank of the group
  2. min: lowest rank in the group
  3. max: highest rank in the group
  4. first: ranks assigned in order they appear in the array
  5. dense: like ‘min’, but rank always increases by 1 between groups.

method是针对rank排名讲的,指的是原始数据序列中存在相同的数据,这些相同数据返回的rank排名,如果是max就取相同数据所占顺序中最大的,min就是其中最小的。first就是按照他们在原始数据中所出现的顺序给定rank。

  • References

转载地址:http://zdge.baihongyu.com/

你可能感兴趣的文章
multiprocessor(中)
查看>>
mysql CPU使用率过高的一次处理经历
查看>>
Multisim中555定时器使用技巧
查看>>
MySQL CRUD 数据表基础操作实战
查看>>
multisim变压器反馈式_穿过隔离栅供电:认识隔离式直流/ 直流偏置电源
查看>>
mysql csv import meets charset
查看>>
multivariate_normal TypeError: ufunc ‘add‘ output (typecode ‘O‘) could not be coerced to provided……
查看>>
MySQL DBA 数据库优化策略
查看>>
multi_index_container
查看>>
MySQL DBA 进阶知识详解
查看>>
Mura CMS processAsyncObject SQL注入漏洞复现(CVE-2024-32640)
查看>>
Mysql DBA 高级运维学习之路-DQL语句之select知识讲解
查看>>
mysql deadlock found when trying to get lock暴力解决
查看>>
MuseTalk如何生成高质量视频(使用技巧)
查看>>
mutiplemap 总结
查看>>
MySQL DELETE 表别名问题
查看>>
MySQL Error Handling in Stored Procedures---转载
查看>>
MVC 区域功能
查看>>
MySQL FEDERATED 提示
查看>>
mysql generic安装_MySQL 5.6 Generic Binary安装与配置_MySQL
查看>>