How can I use a string to access a nested attribute from a form?

Question

I have several elements in a form using Flask WTF with this naming convention...

# req_app_qty
# req_app_note
# req_main_qty  
# req_main_note
# req_side_qty
# req_side_note
# req_bread_qty
# req_bread_note
# continued... 

I can access the form data manually like this...

print "Manually (qty): " , form.req_app_qty.data     # works fine
print "Manually (note): " , form.req_app_note.data   # works fine

But I am trying to access this form data in a more automated fashion...

categories = [ "app", "main", "side", "bread", "dessert", "bev", "uten", "cups", "misc"]
for x in categories:
    field1 = "req_%s_qty.data" % x    # create a string to represent the attributes
    field2 = "req_%s_note.data" % x   # create a string to represent the attributes
    qty_rqst = form.field1.data           # fails
    rqst_note = form.field2.data          # fails

    # also tried        
    print "QTY=", getattr(form, field1)   # fails  
    print "Note:", getattr(form, field2)  # fails

I tried these methods above and they have failed...

First method the lines fail with an error stating that the form does not have an attribute 'field1' or 'field2'.

As for second method of accessing form data, the following lines fail with a error stating there is no attribute 'req_app_qty.data'

print "QTY=", getattr(form, field1)   # fails  

How can I create a string to access these form attributes?

Answer 1

qty_rqst = form.field1.data           # fails

This doesn't work because you're trying to access the field field1, which doesn't exist.

print "QTY=", getattr(form, field1)   # fails

This doesn't work because you're trying to access the field req_X_qty.data, which doesn't exist.

You need to access fields that exist, e.g.

print 'QTY=', getattr(form, 'req_app_qty').data