# Data Preparation-3

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2_data_preparation_3
In [ ]:
###################################################
#  Filename : 2_data_preparation_3                #
#  Purpose : To demonstrate how to construct      #
#   a coding dictionary for a discrete variable.  #
#   We use likelihood encoding.                   #
#  Author : Niel S.                               #
#  (c) The English Tea Company LLC                #
###################################################
import sys
sys.path.append('C:\\Users\\singa72\\Desktop\\Euler\\')

import Euler as Eu
from matplotlib import pyplot as plt

data_work   = data_folder+'data_work.db'

#M A I N   F U N C T I O N
def main():
#Make probability encodings for all the categorical
### variables.
conn = Eu.connection(data_work)
try:

probability_encoding_categorical('marital',conn)
probability_encoding_categorical(varName='job',conn=conn)
probability_encoding_categorical(varName='education',conn=conn)
probability_encoding_categorical(varName='deflt',conn=conn)
probability_encoding_categorical(varName='housing',conn=conn)
probability_encoding_categorical(varName='contact',conn=conn)
probability_encoding_categorical(varName='campaign',conn=conn)
probability_encoding_categorical(varName='month',conn=conn)
probability_encoding_categorical(varName='day_of_week',conn=conn)
probability_encoding_categorical(varName='poutcome',conn=conn)
probability_encoding_categorical(varName='y',conn=conn)

Eu.run('select * from y_coding',conn)

#Challenge : Suggest a way to reduce the number of lines
## in the code above.

except Exception as err:
Eu.print_error(err)
finally:
conn.close()

def probability_encoding_categorical(varName,conn):
try:
sql = '''
DROP TABLE if exists ?vvar?_coding;
CREATE TABLE ?vvar?_coding AS
SELECT
?vvar?,
CASE
WHEN n_ppl_all*n_ppl_pass IS 0 THEN 0.0001
ELSE round(n_ppl_pass/n_ppl_all,4) END code
FROM
(
SELECT
?vvar?,
sum( CASE WHEN Y = 'yes' THEN 1. ELSE 0 END) n_ppl_pass,
count(*) n_ppl_all
from bank
group by ?vvar?
) as T1
'''.replace('?vvar?',varName)

Eu.execute(sql,conn=conn)

except Exception as err:
Eu.print_error(err)

def main_alternative():
conn = Eu.connection(data_work)
try:
cat_vars = ('marital','job', 'education', 'deflt',
'housing','contact','campaign','month',
'day_of_week','poutcome','y')

for cat_var in cat_vars:
probability_encoding_categorical(varName='y',conn=conn)
Eu.run('select * from ?vv?_coding'.replace('?vv?',cat_var)
,conn)

except Exception as err:
Eu.print_error(err)
finally:
conn.close()

if __name__ == '__main__':
main()

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