python利用pandas和xlrd读取excel，特征筛选列

利用xlrd读取excel
筛选0值超过99%的列，并删除

import xlrd
workbook=xlrd.open_workbook(r"123.xlsx")
table = workbook.sheet_by_name('Sheet1')
nrows=table.nrows
ncols=table.ncols
del_col=[]
for j in range(ncols) :
 sum = 0
 for ai in table.col_values(j):
 if ai == 0.0 :
 sum+=1
 if float(sum)/nrows>=0.99:
 del_col.append(j)
print del_col

利用pandas读取excel
筛选0值超过99%的列，并删除

import pandas as pd
df1=pd.read_csv(r"123.csv")
df=pd.DataFrame(df1)
nrows=df.shape[0]
ncols=df.columns.size
del_col=[]
for j in range(ncols) :
 sum = 0
 for ai in df.iloc[:,j]:
 if ai == 0.0 :
 sum+=1
 if float(sum)/nrows>=0.99:
 del_col.append(j)
print del_col