数据预处理算法_11_排序

#!/usr/bin/env python
# -*- coding:utf-8 -*-

# 

def execute():
    '''
    载入模块
    '''
    import pandas as pd
    from sqlalchemy import create_engine
    '''
    连接数据库
    '''
    engine = create_engine('mysql+pymysql://root:123123qwe@127.0.0.1:3306/analysis')
    '''
    选择目标数据
    '''
    params = {
        "columns": "score",
        "by": 'score',
        "ascending": 'True',    # ascending这个参数的默认值是True，按照升序排序，当传入False时，按照降序进行排列
        "na_position": 'first'   # na_position是针对DataFrame中的空缺值的，默认值是last表示将空缺值放在排序的最后，也可以传入first放在最前
    }
    inputs = {"table": 'test'}
    sql = 'select ' + params['columns'] + ' from ' + inputs['table']
    data_in = pd.read_sql_query(sql, engine)
    '''
    排序
    '''
    data_out = data_in.sort_values(by=params['by'],
                                   ascending=eval(params['ascending']),
                                   na_position=params['na_position'])
    '''
    将结果写出
    '''
    print(data_out)
    '''
    数据示例
       score
    2    NaN
    4    4.0
    3    5.0
    1   20.0
    5   20.0
    0   80.0
    '''
# 

if __name__ == '__main__':
    execute()