Can a ui.input value be bound to a list element?

[flintcreek]

Question

I am trying to bind (both ways) the value of a ui.input() to an element of a python list. I understand how to bind "from" the list element using backward=lambda v: v[1], but can't figure out how to bind the input's value "to" the list element. I think I would need to use the "forward" parameter in the bind_value() call, but don't know what to put in there to make it work.

[ed2050]

I don't think it's possible directly. bind_value_to needs a reference to bind to, given as object ref and property name (string). When updating value, it does something like object.setattr (name, newvalue) internally. I'm not aware of a way to access list items by a string name - that's what a dict does.

You could whip up a convoluted solution using a custom helper class or a UserList that takes a key name and gets / sets a specified item in the list. But not a good idea. At that point you're just reinventing a dict poorly.

Can you change your data structure to be a dict instead of a list? That would be a cleaner solution.

If not, perhaps you can change your list to an index. Instead of mylist = ['abc', 'def'] you could do:

mydict = { 'foo' : 'abc', 'bar' : 'def'}
mylist = list (mydict)

# accessing values
value = mydict [ mylist [0] ]

# binding
ui.input ().bind_value (target_object = mydict, target_name = mylist [0])

[flintcreek]

ed2050: Thanks for the ideas! I ended up using something like this:

mydict = { 1 : 'abc', 2 : 'def'}
ui.input().bind_value(mydict, 1)

[ed2050]

Doh! That would be a simpler way. 😄