how to update a database field with a random value selected from a list using random.choice()

[mostwanted]

I thought it would be easy but its not, wrong values are being selected from wrong lists! After submitting a form I wanna check to see if the session field is either a single_session, double_session, evening_single_session or evening_double_session, depending on what it is I want time to be selected randomly from an appropriate list and inputted into the session_time field but wrong values from wrong lists are entered, information gets mixed up!

model code:

db.define_table('lecture',
                Field('subject_name', 'reference subject'),
                Field('department', 'reference departments'), #HERE
                Field('theLevels', label=SPAN('Levels'), requires=IS_IN_SET(['1.1', '1.2', '2.1', '2.2', '3.1', '3.2', '4.1', '4.2'], zero='---Select A Level---')), #HERE
                Field('lecturer', 'reference lecturer'),
                Field('class_session', requires=IS_IN_SET(['single session', 'double session', 'evening single session', 'evening double session'], zero='----Select A Session Period----')),
                Field('session_time', readable=False, writable=False),
                Field('class_room', readable=False, writable=False),
                Field('controller', readable=False, writable=False)
               )

single_session_times=['0830-0930hrs', '0930-1030hrs', '1100-1200','1200-1300', '1400-1500', '1500-1600', '1600-1700']
double_session_times=['0830-1030', '1100-1300', '1400-1700']

evening_single_session_times=['1730-1830', '1830-1930']
evening_double_session_times=['1730-1930']
'''
After submitting the form, have system scheck the session, if the session is any of whats defined give it a proper time
'''
if db.lecture.class_session=='single session':
    the_time=random.choice(single_session_times)
    db.lecture.session_time.default=the_time

   
elif db.lecture.class_session=='evening single session':
    the_time=random.choice(evening_single_session_times)
    db.lecture.session_time.default=the_time

   
elif db.lecture.class_session=='double session':
    the_time=random.choice(double_session_times)
    db.lecture.session_time.default=the_time

   
elif db.lecture.class_session=='evening double session':
    the_time=random.choice(evening_double_session_times)
    db.lecture.session_time.default=the_time

How can i achieve this with proper results from the intended list

Mostwanted

[villas]

Before submission of form, use JS.

or

After submission,  allocate the time in the controller using onvalidation.  See  http://www.web2py.com/books/default/chapter/29/07/forms-and-validators#onvalidation

[mostwanted]

Thank you Villas, i updated my controller like this & its giving results. I a sure there is a better way to do this, a ore cleaner way & if anyone cares to improve my code please dont hesitate so i could update mine & learn more:

def my_form_processing(form):
    if form.vars.class_session=='single session':

        single_session_times=['0830-0930hrs', '0930-1030hrs', '1100-1200','1200-1300', '1400-1500', '1500-1600', '1600-1700']

        the_time=random.choice(single_session_times)
        form.vars.the_time2=the_time

    if form.vars.class_session=='evening single session':
        evening_single_session_times=['1730-1830', '1830-1930']
        the_time=random.choice(evening_single_session_times)
        form.vars.the_time2=the_time

    if form.vars.class_session=='double session':

        double_session_times=['0830-1030', '1100-1300', '1400-1700']

        the_time2=random.choice(double_session_times)
        form.vars.the_time2=the_time2

    if form.vars.class_session=='evening double session':
        evening_double_session_times=['1730-1930']
        the_time=random.choice(evening_double_session_times)
        form.vars.the_time2=the_time

@auth.requires_login()
def index():
    form=SQLFORM(db.lecture)
    if form.process(onvalidation=my_form_processing).accepted:
        response.flash=T('Lecture Entered')
    return locals()

Regards;

Mostwanted

[villas]

We all have our styles of programming.  I would probably create a dict of times.

But any idea which works is fine. Everyone looks at their old code and sees a better way.

My motto is:  get something working and move on! 

[AGRogers]

>>>My motto is:  get something working and move on! 

Haha. A modified version I need to remember: Get something working and don't go back and break it! 

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[mostwanted]

Hahahaha sometimes you put in a single delimeter & it all comes down crumbling!

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[mostwanted]

The dictionary makes it less cubersome:

def my_form_processing(form):
    times=dict({'single_session_times':['0830-0930hrs', '0930-1030hrs', '1100-1200','1200-1300', '1400-1500', '1500-1600', '1600-1700'], 'evening_single_session_times':['1730-1830', '1830-1930'],'double_session_times':['0830-1030', '1100-1300', '1400-1700'],'evening_double_session_times':['1730-1930']})


    if form.vars.class_session=='single session':
        the_time=random.choice(times['single_session_times'])

        form.vars.the_time2=the_time

    if form.vars.class_session=='evening single session':

        the_time=random.choice(times['evening_single_session_times'])

        form.vars.the_time2=the_time

    if form.vars.class_session=='double session':

        the_time2=random.choice(times['double_session_times'])

        form.vars.the_time2=the_time2

    if form.vars.class_session=='evening double session':

        the_time=random.choice(times['evening_double_session_times'])

        form.vars.the_time2=the_time

@auth.requires_login()
def index():
    form=SQLFORM(db.lecture)
    if form.process(onvalidation=my_form_processing).accepted:
        response.flash=T('Lecture Entered')
    return locals()

Thank you guys, much appreiated.

[villas]

Hi Mostwanted

We always can optimise our code.

The dict could have keys for each possible session. Then you only need one line to produce a random time.

Maybe your onvalidation only requires two lines of code!

Please look at this...




def my_form_processing(form):
    times = {

'single session':['0830-0930hrs', '0930-1030hrs', '1100-1200','1200-1300', '1400-1500', '1500-1600', '1600-1700'],


'evening single':['1730-1830', '1830-1930'],

'double session':['0830-1030', '1100-1300', '1400-1700'],

'evening double':['1730-1930']

}
    form.vars.the_time2 = random.choice(times[form.vars.class_session])

[mostwanted]

This is very impressive Villas, you see, this is what I meant by a better way of doing this, thank you.