我将以下数据存储在 csv (df_sample.csv) 中。我将列名放在名为 cols_list 的列表中。
df_数据_样本:
df_data_sample = pd.DataFrame({
'new_video':['BASE','SHIVER','PREFER','BASE+','BASE+','EVAL','EVAL','PREFER','ECON','EVAL'],
'ord_m1':[0,1,1,0,0,0,1,0,1,0],
'rev_m1':[0,0,25.26,0,0,9.91,'NA',0,0,0],
'equip_m1':[0,0,0,'NA',24.9,20,76.71,57.21,0,12.86],
'oev_m1':[3.75,8.81,9.95,9.8,0,0,'NA',10,56.79,30],
'irev_m1':['NA',19.95,0,0,4.95,0,0,29.95,'NA',13.95]
})
attribute_dict = {
'new_video': 'CAT',
'ord_m1':'NUM',
'rev_m1':'NUM',
'equip_m1':'NUM',
'oev_m1':'NUM',
'irev_m1':'NUM'
}
然后我阅读每一列并进行一些数据处理,如下所示:
cols_list = df_data_sample.columns
# Write to csv.
df_data_sample.to_csv("df_seg_sample.csv",index = False)
#df_data_sample = pd.read_csv("df_seg_sample.csv")
#Create empty dataframe to hold final processed data for each income level.
df_final = pd.DataFrame()
# Read in each column, process, and write to a csv - using csv module
for column in cols_list:
df_column = pd.read_csv('df_seg_sample.csv', usecols = [column],delimiter = ',')
if (((attribute_dict[column] == 'CAT') & (df_column[column].unique().size <= 100))==True):
df_target_attribute = pd.get_dummies(df_column[column], dummy_na=True,prefix=column)
# Check and remove duplicate columns if any:
df_target_attribute = df_target_attribute.loc[:,~df_target_attribute.columns.duplicated()]
for target_column in list(df_target_attribute.columns):
# If variance of the dummy created is zero : append it to a list and print to log file.
if ((np.var(df_target_attribute[[target_column]])[0] != 0)==True):
df_final[target_column] = df_target_attribute[[target_column]]
elif (attribute_dict[column] == 'NUM'):
#Let's impute with 0 for numeric variables:
df_target_attribute = df_column
df_target_attribute.fillna(value=0,inplace=True)
df_final[column] = df_target_attribute
attribute_dict 是一个字典,其中包含变量名称:变量类型的映射:
{
'new_video': 'CAT'
'ord_m1':'NUM'
'rev_m1':'NUM'
'equip_m1':'NUM'
'oev_m1':'NUM'
'irev_m1':'NUM'
}
但是,这种逐列操作需要很长时间才能在大小**(500 万行 * 3400 列)**的数据集上运行。目前运行时间约为
12 小时以上。
我想尽可能减少这种情况,我能想到的方法之一是一次对所有 NUM 列进行处理,然后逐列进行处理
为 CAT 变量。
然而,我既不确定 Python 中的代码可以实现这一点,也不确定这是否会真正加快该过程。
有人可以帮我吗!