Long sorted dropdown list with WTForms

问题

I'd like to create a drop-down list of the U.S. states in alphabetical order. I've converted a tuple of states into an OrderedDict and I'm feeding this into my WTForms SelectField.

import collections
import wtforms

STATE_ABBREV = ('AL', 'AK', 'AZ', 'AR', 'CA', 'CO', 'CT', 'DE', 'FL', 'GA', 
                'HI', 'ID', 'IL', 'IN', 'IO', 'KS', 'KY', 'LA', 'ME', 'MD', 
                'MA', 'MI', 'MN', 'MS', 'MO', 'MT', 'NE', 'NV', 'NH', 'NJ', 
                'NM', 'NY', 'NC', 'ND', 'OH', 'OK', 'OR', 'PA', 'RI', 'SC', 
                'SD', 'TN', 'TX', 'UT', 'VT', 'VA', 'WA', 'WV', 'WI', 'WY')

def list_to_ordered_pairs(input_list):
    ordered_pairs = collections.OrderedDict()
    for item in input_list:
        ordered_pairs[item] = item
    return ordered_pairs

state_pairs = list_to_ordered_pairs(STATE_ABBREV)

class MyForm(wtforms.Form):
    state = wtforms.SelectField(label='State', choices=state_pairs)

My problem is that the resulting dropdown menu shows only the second letter of each state...

How do I fix this up to show the proper two-letter designation? And is there a better approach to pulling in various geographic regions?

回答1:

There are a few issues here:

Your list isn't a list its a 50-tuple.

STATE_ABBREV = ('AL', 'AK', 'AZ', 'AR', 'CA', 'CO', 'CT', 'DE', 'FL', 'GA', 
                'HI', 'ID', 'IL', 'IN', 'IO', 'KS', 'KY', 'LA', 'ME', 'MD', 
                'MA', 'MI', 'MN', 'MS', 'MO', 'MT', 'NE', 'NV', 'NH', 'NJ', 
                'NM', 'NY', 'NC', 'ND', 'OH', 'OK', 'OR', 'PA', 'RI', 'SC', 
                'SD', 'TN', 'TX', 'UT', 'VT', 'VA', 'WA', 'WV', 'WI', 'WY')

If you wanted a list, it would look something like:

STATE_ABBREV = ['AL', 'AK', 'AZ', 'AR', 'CA', 'CO', 'CT', 'DE', 'FL', 'GA', 
                'HI', 'ID', 'IL', 'IN', 'IO', 'KS', 'KY', 'LA', 'ME', 'MD', 
                'MA', 'MI', 'MN', 'MS', 'MO', 'MT', 'NE', 'NV', 'NH', 'NJ', 
                'NM', 'NY', 'NC', 'ND', 'OH', 'OK', 'OR', 'PA', 'RI', 'SC', 
                'SD', 'TN', 'TX', 'UT', 'VT', 'VA', 'WA', 'WV', 'WI', 'WY']

I don't believe your state_pairs are pairs in the sense that you think they are. They are pairs like this

>>> state_pair = 'AK'
>>> abbr, state = state_pair
>>> print abbr
A
>>> print state
K
>>>

I believe state_pair you want would look something like this:

>>> state_pair = ('AK', 'Alaska')
>>> abbr, state = state_pair
>>> print abbr
AK
>>> print state
Alaska
>>>

The solution to the problem you are seeing is to get rid of the method list_to_ordere_pair and just create a list of of state_pairs

STATE_CHOICES = [('AL', 'Alabama'),('AK','Alaska')...]

class MyForm(wtforms.Form):
    state = wtforms.SelectField(label='State', choices=STATE_CHOICES)

回答2:

The WTForms docs call for the choices property to be a sequence of (value, label) pairs. I mistakenly read this as key value pairs and was trying to use a dictionary. This simple list comprehension does the trick...

import wtforms

STATE_ABBREV = ('AL', 'AK', 'AZ', 'AR', 'CA', 'CO', 'CT', 'DE', 'FL', 'GA', 
                'HI', 'ID', 'IL', 'IN', 'IO', 'KS', 'KY', 'LA', 'ME', 'MD', 
                'MA', 'MI', 'MN', 'MS', 'MO', 'MT', 'NE', 'NV', 'NH', 'NJ', 
                'NM', 'NY', 'NC', 'ND', 'OH', 'OK', 'OR', 'PA', 'RI', 'SC', 
                'SD', 'TN', 'TX', 'UT', 'VT', 'VA', 'WA', 'WV', 'WI', 'WY')

class MyForm(wtforms.Form):
    state = wtforms.SelectField(label='State', 
        choices=[(state, state) for state in STATE_ABBREV])

来源：https://stackoverflow.com/questions/23851664/long-sorted-dropdown-list-with-wtforms

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python

forms

wtforms