gistfile1.txt

from sqlalchemy import create_engine

columns = ['flame_retardants',]
engine = create_engine('postgresql:///your_user')

def make_sql(column):
    #x21 = 'update tedx set %s=1 where %s="X"' % (column, column)
    #null20 = 'update tedx set %s=0 where %s is null"' % (column, column)
    sql = "alter table tedx alter %s type bool using case when %s='X' then TRUE else FALSE END;" % (column, column)
    engine.execute(sql)
    return engine.execute('select * from tedx;')

sql_commands = list(map(make_sql, columns))