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Streamlit dynamic UI to generate dynamic input widgets depending on value from a different input widget

I want to open this post as I can't find anything on the official documentation from streamlit or any resources that mentioned how to do this. After some trial and error I have figured out a way, and will post the answer below. This is a function that in R shiny is called dynamic UI, here's the question.
How to generate dynamic input widgets depending on the value from a different input widget? For example see below picture, the numbers of text_input called Product Code i depends on the value from the number_input called Number of Products. So if there are x number of products, there will be x number of text_input generated dynamically. Moreover, the value inside the generated text_input can be extracted as well.

Here is one way to do this.
First, use list comprehension to store keys (variables to use to extract values from text_input later) and values (text_input).
Next, use key and value to set the attribute in a class.
The value from text_input labelled as product2 can be extracted using the attribute within the class using p.product2 for example.
import streamlit as st
number_of_products = st.sidebar.number_input(label="Number of Products",
min_value=0, max_value=20, value=1)
class Products:
pass
p = Products()
keys = [str("product"+str(x+1)) for x in range(number_of_products)]
values = [st.sidebar.text_input(label=f"Product Code {x+1}", value=0) for x in range(number_of_products)]
for key, value in zip(keys, values):
setattr(p, key, value)
# each key's value is stored in the class as an attribute
st.write(p.product2)
Using dictionary and exec command can also dynamically declare variables, but when the value inside the text_input is not a number, it will generate an error.

Generating dynamic input widget content is possible when using streamlit's session state. However, there is a potential drawback of streamlit refreshing the page upon input widget interaction.
One way to solve for this is to create multiple forms. For example, in your case you can create one form for "Number of Products", and update this value to the session state.
Next, you can create another form that takes in this "Number of Products" parameter and creates x number of input widgets.
import streamlit as st
with st.form("Number of Products"):
numProducts = st.number_input('Insert a number', key='numProducts')
submitForm = st.form_submit_button("Set Product Number")
if submitForm:
st.success("Please assign product codes below")
if 'numProducts' in st.session_state.keys():
with st.form("Product Codes"):
for i in range(st.session_state['numProducts']):
# insert text inputs with keys here
Hope this helps!

asigning ids in kivy on the python side

im using kivy. the what im trying to do is have and 'idea',a slider and a label containing the slider's current value in a row in a grid layout
now getting the layout is fine but getting the label to have a text value the same as the slider's current value is tricky. I'm trying to use string concation to refer to the label with the same number suffix as the slider that it is paired with.
I think the problem im having is that im trying to assign ids on the python side when they normally have to be done on the kv side. It's either that or the fact the ids i'm assigning are strings when kv would normally expect plain text. any help would be appreciated
class ScatterTextWidget(FloatLayout):
def run_me(self):
r=1
main_list=self.ids.main_list
main_list.clear_widgets()
main_list.height=0
for idea in imported_ideas:
main_list.add_widget(Label(text=idea,color=(0,0,0,1),id='idea_label_'+str(r)))
main_list.add_widget(Slider(id='Slider_'+str(r),min=0,max=10,value=5, step=1,on_value_pos=self.slider_slid(self)))
main_list.add_widget(Label(color=(0,0,0,1),id='value_label_'+str(r)))
value_label=self.ids['value_label_'+str(r)] # get this working and then apply the method into slider slid
value_label.text='xxx'
main_list.height+=35
r +=1
button_1=self.ids.button_1
button_1.text='Begin'
button_1.bind(on_press=self.begin)
def slider_slid(self,sender):
s=str(sender.id)
value_label=self.ids['value_label_'+str(s[12:])]
value_label.text=str(sender.value)
value_label=self.ids['value_label_'+str(s[12:])]
KeyError: 'value_label_'

self.ids only collects ids from children in the kv language rule of the widget. It doesn't know about widgets you added via python.
You don't need to use the id though. In this case you could keep e.g. a dictionary of id -> widget keys.
self.keys_dict = {}
for idea in imported_ideas:
new_widget = Label(color=(0,0,0,1),id='value_label_'+str(r)))
main_list.add_widget(new_widget)
self.keys_dict['value_label_' + str(r)] = new_widget
Then later you can access it with self.keys_dict['value_label_' + str(s[12:])] or whatever you like.
I suppose in practice you could also modify the actual ids dictionary in the same way, though I subjectively feel it is preferable to maintain your own dictionary with a name that represents its more specific contents.

Kivy dynamic widget issue

Well, i'm a beginner using kivy framework, so i thought that someone here could help me.
My question is:
On my app, the user input a number n, then the app return n TextInput widgets. But how can i use the values inserted on each TextInput? The first part is easy to do, i did it by a list. (If someone know how to do it directly on kv file i would appreciate it). My issue is on second part, i need to use and manipulate these values (in TextInputs) later but i can't reach to them. I mean, i set up for each widget in the list an id, but i can't reach to .text attribute of them. Here is a piece of my code:
class FirstLayout(BoxLayout):
def next_layout(self):
self.clear_widgets()
secondLayout = Factory.SecondLayout()
number = NumericProperty()
# This 'number' variable came from another widget on kv file
textinput_list = []
# That list will receive as many TextInputs field as my variable 'number' said (by the loop for)
for i in range(int(self.number.text)):
textinput_list.append(TextInput())
textinput_list[i].id = "input" + str(i + 1)
# So for each textinput, i added a id named 'inputx' (where x is the number of the current
# iteration) my question resides here. How could i use those values (inside of each textinput
# on this list
# later? Because i'm not creating these widgets (TextInputs) on kv language so i don't know how to
# bind the ids for a new variable directly in .py file
secondLayout.container.add_widget(textinput_list[i])
self.add_widget(secondLayout)

If I understand your question right, you just have to make textinput_list a class variable. So this.
textinput_list = []
becomes
self.textinput_list = []
Lets say you have an object of FirstLayout called first. With first.textinput_list[0] you can access the first textinput and so on.
If you want to easily access the textinputs via id I would suggest using a dictionary, with the keys being the id's and the values being the inputs.

Getting multiple wx widget values with Event Handling

CODE: http://pastebin.com/W4uXmazw
I would like to memorize how to get values from any wx widget with event handling after clicking a wx.Button.
In my program i have two fields, the new filename and the contents.
What are the steps i have to take in order to get the values from each field?
From there, i can use pythons f.open and f.write methods to complete my application.
Thanks!

If you want to get value of a widget, then you need to make that widget accessible throughout the entire class. To do that, you need to make the variable for the widget into an instance variable. So instead of adding the text control directly to the sizer, you'll want to do something like this:
self.newfilename = wx.TextCtrl(panel,-1), 0, wx.TOP, 5)
self.contents = wx.TextCtrl(panel,-1,size=(390,150),style = wx.TE_MULTILINE|wx.TE_PROCESS_TAB)
Then in your button's event handler, you can just do something like this:
valueOne = self.newfilename.GetValue()
contents = self.contents.GetValue()
The other way to do it would be to use your panel. If you use "self.panel", then you could grab all its children via its GetChildren method and then iterate over the list and use Python's "isinstance" builtin to check what kind of widget you're accessing. If you have set the widget's name, you can check that too.

ListCtrl - wxPython / Python

My question is if we can assign/bind some value to a certain item and hide that value(or if we can do the same thing in another way).
Example: Lets say the columns on ListCtrl are "Name" and "Description":
self.lc = wx.ListCtrl(self, -1, style=wx.LC_REPORT)
self.lc.InsertColumn(0, 'Name')
self.lc.InsertColumn(1, 'Description')
And when I add a item I want them to show the Name parameter and the description:
num_items = self.lc.GetItemCount()
self.lc.InsertStringItem(num_items, "Randomname")
self.lc.SetStringItem(num_items, 1, "Some description here")
Now what I want to do is basically assign something to that item that is not shown so I can access later on the app.
So I would like to add something that is not shown on the app but is on the item value like:
hiddendescription = "Somerandomthing"
Still didn't undestand? Well lets say I add a button to add a item with some other TextCtrls to set the parameters and the TextCtrls parameters are:
"Name"
"Description"
"Hiddendescription"
So then the user fills this textctrls out and clicks the button to create the item, and I basically want only to show the Name and Description and hide the "HiddenDescription" but to do it so I can use it later.
Sorry for explaining more than 1 time on this post but I want to make sure you understand what I pretend to do.

Instead of using the ListCtrl as your data structure, you could keep a separate list/dict of objects that contain all the information you want and refresh the ListCtrl from your other data structure.
For example:
class MyObject(object):
def __init__(self, name, description, hidden_description):
self.name = name
self.description = description
self.hidden_description = hidden_description
Then in your application:
def __init__(self):
self.my_items = {}
self.lc = wx.ListCtrl(self, -1, style=wx.LC_REPORT)
self.lc.InsertColumn(0, 'Name')
self.lc.InsertColumn(1, 'Description')
def addItemToMyListCtrl(self, name, description, hidden):
new_item = MyObject(name, description, hidden)
self.my_items[name] = new_item
self.lc.Append((new_item.name, new_item.description))
Then when you want to use your additional data you can just look up the correct item in the dictionary and your data will be there.

the wxListCtrl lets you associate arbitrary data with an item, that will not be displayed - read the docs for the following methods:
SetItemData
GetItemData
FindItemData
The wxListItem class also has GetData and SetData methods.

You could always set the width of the hidden column to zero, that might accomplish what you want. I just tried it in a C++ (non-wx) program and it worked fine.

wx.ListCtrl doesn't let you associate a python object with an item like wx.TreeCtrl does with its extremely useful SetPyData() method (and corresponding GetPyData()).
I haven't tried it myself, but there is code here that shows how to create a class to mix in python data with a list. Although I'll admit, it's not clear to me how you're meant to use it.
It also might be possible to directly inherit from wx.ListCtrl, and add the appropriate methods, but I haven't seen any attempts at that anywhere, so it may be harder than I'm thinking.
Alternately you can just use SetItemData() to store an int in each item, and use that int to index a dict (or list, if the items are ordered reliably and consistently) that contains the associated objects. tgray has already shown how to do this, and it's listed at the page I link above as well, so I won't go over it again.