asked on

Python - problem with if/elif and use of default table value

I have a mysql table with one of the columns ALPAID_ytd acting as a switch. The default value for the column is 0 (zero) and this represents the off position. The column is changed to a value of 1 when the switch is on. This switch is programmed on/of as the user deploys the application. Below is an image of the mysql panel showing the setup.

While I have no problems switching on/off and updating the table, I have a major probLem in using the values in a set of if/elif filters which feed a table with purchase information. For example

if ALPAID_ytd != 0 and status == 1:
            print ("elif ALPAID_ytd != 0 and status == 1: fired")
            
        elif ALPAID_ytd != 1 and status == 1:
            print("elif ALPAID_ytd != 1 and status == 1: fired")

Open in new window

In the above, !=0 gets me the value 1. No problem
However, != 1 does not resolve to 'NOT EQUAL 1' (zero) but rather to !=0 which is 1. ==0 resolves exactly the same way.
Consequently it is not possible to run the filters as I cannot catch the value 0.

Here is an output example showing the problem. Note that the actual value of ALPAID_ytd is 0, but 1 gets inserted into the if/elif code.

Finally, here is the code from my testing page. I have set the value of ALPAID_ytd to 0 (the problem value). The variable "status" is a descriptor for the order (mylist). There are three possibilities which are defined by the mylist sublists

2 ........ eg mylist = ['1008', [4], [4], [4]]
0......... eg mylist = ['1008', [4], [29], [4]]
1 ..........eg mylist = ['1008', [29], [29], [29]]

You could plug these into line 88 of the code to use different values of "status" - although I do not believe this is connected to the problem

Hopefully you can spot a solution (excluding changing the default value of ALPAID_ytd to 0 !!)

James

#!C:\Python34\python.exe
import collections
import cgi,cgitb
import mysql.connector as conn
def htmlTop():
    print("""Content-type:text/html\n\n
        <!DOCTYPE html>
        <html lang="en">
            <head>
                <meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1">
                <title> My Server-side template</title>
        </head>
        <body>""")

def htmlTail():
    print(""" its done</body>
        </html>""")

def connectDB():
    db=conn.connect(host='localhost' ,user='root' ,passwd='844cheminduplan' ,db='office')
    cursor = db.cursor()
    return db, cursor 


    
def activityinfo(db,cursor,courseNumber):
    cursor.execute("""select courseNumber,Activity, tariffstwelve, tariffsthirtysix from activities WHERE courseNumber = "%s" """
    %(courseNumber)) 
    activitydata = cursor.fetchall()
    return activitydata



    
def SelectALPAID_ytd(db,cursor):
    cursor.execute("""select ALPAID_ytd from registrations WHERE memberID = "%s" """
    %(memberID)) 
    ALPAID_ytd=cursor.fetchall()
    return ALPAID_ytd



def OrderProfiler(mylist,db,cursor):
    # provides a list of 1s nd 0eros to describe the list in terms of paid and activity libre activities
    OrderProfile = []
    #del mylist[0] # chopping off the memberID
    mylist = mylist[1]  +  mylist[2]  + mylist[3]
    print(mylist, "this is mylist")
    for each in mylist:
        courseNumber = each
        activitydata =  activityinfo(db,cursor,courseNumber)
        #print(activitydata, "this is activity data")
        #Note activitydata[0][2] is price for 12 trim and activitydata[0][3] is for 36 trim
        if activitydata[0][2] == 0 and activitydata[0][3] == 0:
            OrderProfile.append(0) #activityLibre
        elif activitydata[0][2] >0 and activitydata[0][3] > 0:
            OrderProfile.append(1) # paid
    return OrderProfile
    
def StatusFinder (OrderProfile):
    # declares an order as being mixed (0), activity libre only(1) or paid only(2) items
    # uses OrderProfile list from OrderProfiler(mylist, db, cursoro) above
    # this status along with the ALPAID_YTD flag  in registrations table determines if DELTA ORDER should be
    # charged the activity libre registration fee, or should be reimboursed the activity libre registration fee
    print (collections.Counter(OrderProfile))
    OrderProfileCount = (collections.Counter(OrderProfile))
    if OrderProfile.count(1) >0 and OrderProfile.count(0) >0:
        print(OrderProfile, "OrderProfile")
        status = 0 #mixed
    elif OrderProfile.count(1) >0 and OrderProfile.count(0)== 0:
        status = 2 #paid_only
    elif OrderProfile.count(1) ==0 and OrderProfile.count(0)>0:
        status = 1 #free_only
    return status
        
        




#main program
if __name__== "__main__":
    try:
        htmlTop()
        
        print("--------------------------------------------------------------")
        db,cursor=connectDB()
        mylist = ['1008', [29], [29], [29]]
        OrderProfile = OrderProfiler(mylist,db,cursor)
        status = StatusFinder (OrderProfile)
        print(status, "this is order status")
        memberID = mylist[0]
        print (memberID, "this is memberID")
        ALPAID_ytd = SelectALPAID_ytd(db,cursor)
        ALPAID_ytd = ALPAID_ytd [0][0]
        print(ALPAID_ytd, "this is ALPAID_ytd - the on/off switch. Default in table is 0(off) and 1(on)")
            
        print("..........................................")
        
                       
            
        if ALPAID_ytd != 0 and status == 1:
            print ("elif ALPAID_ytd != 0 and status == 1: fired")
            
        elif ALPAID_ytd != 1 and status == 1:
            print("elif ALPAID_ytd != 1 and status == 1: fired")
            
        elif ALPAID_ytd != 0 and status == 2:
            print ("elif ALPAID_ytd != 0 and status == 2: fired")        
            
        elif ALPAID_ytd != 1 and status == 2:
            print ("elif ALPAID_ytd != 1 and status == 2:fired")
            
           
        elif ALPAID_ytd != 0 and status == 0:
            print ("elif ALPAID_ytd != 0 and status == 0: fired")        

        elif ALPAID_ytd != 1 and status == 0:
            print ("elif ALPAID_ytd != 1 and status == 0:fired")        
            
        else:
            print("no result")
            
        
                
        
        htmlTail()
    except:
        cgi.print_exception()

Open in new window

ASKER CERTIFIED SOLUTION

Mark Brady

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

Nas-Banov

The table stores the values as strings and as such you get in `ALPAID_ytd` the strings '0' and '1' - not the numbers 0 and 1 your if's are checking for. As such, your != comparisons will be always false

>>> '0'!=0, '0'!=1, '1'!=0, '1'!=1
(True, True, True, True)

Open in new window

In your code as-is, just change to check for '0' and '1' strings. Long term, maybe check for equality rather than inequality (that might have helped you to spot the problem earlier. maybe)

jameskane

ASKER

Mark and Nas,

PROBLEM SOLVED !!!!

Many thanks to you both for the help. and insight.

Guess I need to swot up some on mysql server !!

James