pandas groupby重写Q3

-- coding: utf-8 --

“””
Created on Thu Jul 09 20:31:38 2015

@author: Administrator
“”“

import pandas as pd
import numpy as np
import os

InputDir = r’D:\R\P’

rootdir = InputDir

pieces = []

for parent,dirnames,filenames in os.walk(rootdir):

 for filename in filenames:

    dayhourmin = filename.split('_')[4]
    day = dayhourmin[4:8]
    hour = dayhourmin[8:10]
    minute = dayhourmin[10:12]

    df=pd.read_csv(os.path.join(parent,filename),skiprows=3,header=None,nrows=8,sep=' ').iloc[:,2]
    #取第三列速度
    frame=df.T
    frame['day'] = day
    frame['hour'] = hour
    frame['minute'] = minute
    pieces.append(frame)
    wholeItem = pd.concat(pieces,axis = 1,ignore_index=True).replace('/',np.nan).T.astype(np.float)
    print wholeItem.dtypes
    #注意元素类型

aver = wholeItem.groupby([‘day’,’hour’]).mean().add_prefix(‘mean_’)
all = pd.merge(wholeItem,aver,left_on=[‘day’,’hour’],right_index=True)

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