Solara•8mo ago

Initializing function.

Please help me make an initializing function. I'm using the solara.use_router().search function to get a data. For example, I use this data as values in solara.Select. I have a problem that after changing the value in select and clicking the button, the value returns to the one I set during initialization. Therefore, I want to write a function that will be called only once when first launched, receive data, write it to several solara.reactive (I have a lot of them), and then not run.

8 Replies

MaartenBreddels•8mo ago

In a component you can use https://solara.dev/documentation/api/hooks/use_effect If you use it for the intial state of use_reactive, you can also consider using https://solara.dev/documentation/api/hooks/use_memo Hope this helps, otherwise please share the code. Regards,

icecream4OP•8mo ago

Right now my code looks like this. And I don’t know how to separate initialization using data into a separate function.

import f1, а2

text = solara.reactive(None)

a_values = solara.reactive(None)
a_value = solara.reactive(None)

b_values = solara.reactive(None)
b_value = solara.reactive(None)

c_value = solara.reactive(None)
d_value = solara.reactive(None)
e_value = solara.reactive(None)
f_value = solara.reactive(None)
g_value = solara.reactive(None)

def on_click():
    c_value = f1(a_value, b_value)
    ...

def collect_data(query_string):
    # Parsing strings and get data from database
    ...

    
@solara.component
def Page():
    query_string = solara.use_router().search
    
    data = collect_data(query_string)

    text.value = f"Default text: {data["text"]}"

    solara.InputText(label="Text:", value=text, continuous_update=True)

    a_values.value = list(data["a"].keys())
    a_value.value = a_values.value[0]

    b_values.value = list(data["b"].keys())
    b_value.value = b_values.value[0]

    (d_value.value, e_value.value, f_value.value, g_value.value) = f2(data)

    solara.Select(label="Select:", value=a_value, values=a_values.value)
    solara.Select(label="Select:", value=b_value, values=b_values.value)

    solara.Button(label="CLICK", on_click=on_click)
    ...

import f1, а2

text = solara.reactive(None)

a_values = solara.reactive(None)
a_value = solara.reactive(None)

b_values = solara.reactive(None)
b_value = solara.reactive(None)

c_value = solara.reactive(None)
d_value = solara.reactive(None)
e_value = solara.reactive(None)
f_value = solara.reactive(None)
g_value = solara.reactive(None)

def on_click():
    c_value = f1(a_value, b_value)
    ...

def collect_data(query_string):
    # Parsing strings and get data from database
    ...

    
@solara.component
def Page():
    query_string = solara.use_router().search
    
    data = collect_data(query_string)

    text.value = f"Default text: {data["text"]}"

    solara.InputText(label="Text:", value=text, continuous_update=True)

    a_values.value = list(data["a"].keys())
    a_value.value = a_values.value[0]

    b_values.value = list(data["b"].keys())
    b_value.value = b_values.value[0]

    (d_value.value, e_value.value, f_value.value, g_value.value) = f2(data)

    solara.Select(label="Select:", value=a_value, values=a_values.value)
    solara.Select(label="Select:", value=b_value, values=b_values.value)

    solara.Button(label="CLICK", on_click=on_click)
    ...

MaartenBreddels•8mo ago

if you put all that initialization code in a function that gets called by use_effect, it will only be called once, does that make sense?

icecream4OP•8mo ago

Yes it does, but for some reason it didn't work out for me. I made this code:

def start():
    ...

@solara.component
def Page():
    solara.use_effect(start)
    ...

def start():
    ...

@solara.component
def Page():
    solara.use_effect(start)
    ...

It seems that the "start" function is not called because no one reactive variable is filled.

MaartenBreddels•8mo ago

you should do use_effect(start, dependencies=[]) otherwise it will stil run on each render. I guess looking at the rest of the code you might want to do the following for correctness (although I don't think query_string can change in your case): solara.use_effect(lambda: start(query_string), dependencies=[query_string])

icecream4OP•8mo ago

Hmm, thank you. I tried to rewrite my code here. And it turns out that my error is slightly different:

text = solara.reactive(None)

a_values = solara.reactive(None)
a_value = solara.reactive(None)

b_values = solara.reactive(None)
b_value = solara.reactive(None)

c_values = solara.reactive(None)
d_value = solara.reactive(None)
e_value = solara.reactive(None)
f_value = solara.reactive(None)
g_value = solara.reactive(None)

res_value = solara.reactive(None)
btn = solara.reactive(False)

def on_click():
    res_value.value = a_value.value + b_value.value
    btn.value = True
    
def collect_data():
    return {
        "text": "aaa",
        "a": {"a":"a", "b":"b", "c":"c"},
        "b": {"d":"d", "e":"e", "f":"f"}, 
        "c": "c",
        "d": "d",
        "e": "e",
        "f": "f",
        "g": "g",
    }


def f2(data):
    return (data["d"], data["e"], data["f"], data["g"])


def start():
    data = collect_data()

    text.value = f"Default text: {data['text']}"

    solara.InputText(label="Text:", value=text, continuous_update=True)

    a_values.value = list(data["a"].keys())
    a_value.value = a_values.value[0]

    b_values.value = list(data["b"].keys())
    b_value.value = b_values.value[0]

    c_values.value = {i:solara.use_reactive(False) for i in data["b"]}

    (d_value.value, e_value.value, f_value.value, g_value.value) = f2(data)


@solara.component
def Page():    
    solara.use_effect(start, dependencies=[])
    
    solara.Select(label="Select:", value=a_value, values=a_values.value)
    solara.Select(label="Select:", value=b_value, values=b_values.value)

    solara.Markdown("Switch:")
    toggle = [
        solara.Switch(label=label, value=c_values.value[label])
        for label in c_values.value]
        
    solara.Button(label="CLICK", on_click=on_click)

    if btn.value:
        solara.Markdown(res_value.value)

Page()

text = solara.reactive(None)

a_values = solara.reactive(None)
a_value = solara.reactive(None)

b_values = solara.reactive(None)
b_value = solara.reactive(None)

c_values = solara.reactive(None)
d_value = solara.reactive(None)
e_value = solara.reactive(None)
f_value = solara.reactive(None)
g_value = solara.reactive(None)

res_value = solara.reactive(None)
btn = solara.reactive(False)

def on_click():
    res_value.value = a_value.value + b_value.value
    btn.value = True
    
def collect_data():
    return {
        "text": "aaa",
        "a": {"a":"a", "b":"b", "c":"c"},
        "b": {"d":"d", "e":"e", "f":"f"}, 
        "c": "c",
        "d": "d",
        "e": "e",
        "f": "f",
        "g": "g",
    }


def f2(data):
    return (data["d"], data["e"], data["f"], data["g"])


def start():
    data = collect_data()

    text.value = f"Default text: {data['text']}"

    solara.InputText(label="Text:", value=text, continuous_update=True)

    a_values.value = list(data["a"].keys())
    a_value.value = a_values.value[0]

    b_values.value = list(data["b"].keys())
    b_value.value = b_values.value[0]

    c_values.value = {i:solara.use_reactive(False) for i in data["b"]}

    (d_value.value, e_value.value, f_value.value, g_value.value) = f2(data)


@solara.component
def Page():    
    solara.use_effect(start, dependencies=[])
    
    solara.Select(label="Select:", value=a_value, values=a_values.value)
    solara.Select(label="Select:", value=b_value, values=b_values.value)

    solara.Markdown("Switch:")
    toggle = [
        solara.Switch(label=label, value=c_values.value[label])
        for label in c_values.value]
        
    solara.Button(label="CLICK", on_click=on_click)

    if btn.value:
        solara.Markdown(res_value.value)

Page()

Can you please take a look at it, it seems like I'm trying to use the Switch incorrectly.

MaartenBreddels•8mo ago

you cannot use use_reactive in a loop like this, you should use solara.reactive(). Also use_effect executes after the function returns, so c_values.values is still empty, you could use use_memo in this case:

import solara
text = solara.reactive(None)

a_values = solara.reactive(None)
a_value = solara.reactive(None)

b_values = solara.reactive(None)
b_value = solara.reactive(None)

c_values = solara.reactive(None)
d_value = solara.reactive(None)
e_value = solara.reactive(None)
f_value = solara.reactive(None)
g_value = solara.reactive(None)

res_value = solara.reactive(None)
btn = solara.reactive(False)

def on_click():
    res_value.value = a_value.value + b_value.value
    btn.value = True
    
def collect_data():
    return {
        "text": "aaa",
        "a": {"a":"a", "b":"b", "c":"c"},
        "b": {"d":"d", "e":"e", "f":"f"}, 
        "c": "c",
        "d": "d",
        "e": "e",
        "f": "f",
        "g": "g",
    }


def f2(data):
    return (data["d"], data["e"], data["f"], data["g"])


def start():
    data = collect_data()

    text.value = f"Default text: {data['text']}"

    solara.InputText(label="Text:", value=text, continuous_update=True)

    a_values.value = list(data["a"].keys())
    a_value.value = a_values.value[0]

    b_values.value = list(data["b"].keys())
    b_value.value = b_values.value[0]

    c_values.value = {i:solara.reactive(False) for i in data["b"]}

    (d_value.value, e_value.value, f_value.value, g_value.value) = f2(data)


@solara.component
def Page():    
    solara.use_memo(start, dependencies=[])
    
    solara.Select(label="Select:", value=a_value, values=a_values.value)
    solara.Select(label="Select:", value=b_value, values=b_values.value)

    solara.Markdown("Switch:")
    toggle = [
        solara.Switch(label=label, value=c_values.value[label])
        for label in c_values.value]
        
    solara.Button(label="CLICK", on_click=on_click)

    if btn.value:
        solara.Markdown(res_value.value)

Page()

import solara
text = solara.reactive(None)

a_values = solara.reactive(None)
a_value = solara.reactive(None)

b_values = solara.reactive(None)
b_value = solara.reactive(None)

c_values = solara.reactive(None)
d_value = solara.reactive(None)
e_value = solara.reactive(None)
f_value = solara.reactive(None)
g_value = solara.reactive(None)

res_value = solara.reactive(None)
btn = solara.reactive(False)

def on_click():
    res_value.value = a_value.value + b_value.value
    btn.value = True
    
def collect_data():
    return {
        "text": "aaa",
        "a": {"a":"a", "b":"b", "c":"c"},
        "b": {"d":"d", "e":"e", "f":"f"}, 
        "c": "c",
        "d": "d",
        "e": "e",
        "f": "f",
        "g": "g",
    }


def f2(data):
    return (data["d"], data["e"], data["f"], data["g"])


def start():
    data = collect_data()

    text.value = f"Default text: {data['text']}"

    solara.InputText(label="Text:", value=text, continuous_update=True)

    a_values.value = list(data["a"].keys())
    a_value.value = a_values.value[0]

    b_values.value = list(data["b"].keys())
    b_value.value = b_values.value[0]

    c_values.value = {i:solara.reactive(False) for i in data["b"]}

    (d_value.value, e_value.value, f_value.value, g_value.value) = f2(data)


@solara.component
def Page():    
    solara.use_memo(start, dependencies=[])
    
    solara.Select(label="Select:", value=a_value, values=a_values.value)
    solara.Select(label="Select:", value=b_value, values=b_values.value)

    solara.Markdown("Switch:")
    toggle = [
        solara.Switch(label=label, value=c_values.value[label])
        for label in c_values.value]
        
    solara.Button(label="CLICK", on_click=on_click)

    if btn.value:
        solara.Markdown(res_value.value)

Page()

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icecream4OP•8mo ago

Thank you very much. Yes, it seems to be working now, I'll go check everything 🙂

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Initializing function.