pandas重写Q4

# -*- coding: utf-8 -*-"""Created on Thu Jul 09 20:31:38 2015@author: Administrator"""import pandas as pdimport numpy as npimport osInputDir = r'D:\R\P'rootdir = InputDirpieces = []for parent,dirnames,filenames in os.walk(rootdir):     for filename in filenames:        df=pd.read_csv(os.path.join(parent,filename),skiprows=3,header=None,nrows=8,sep=' ').iloc[:,2]        pieces.append(df)        sudu = pd.concat(pieces,axis = 1,ignore_index=True).replace('/////',np.nan).astype(np.float)        #print sudu.dtypes        #转换成矩阵做减法，再转回dataframearr = sudu[3:].values - sudu[:-3].valuesfengqiebian = pd.DataFrame(arr)