How to make a clickable URL in Shiny for Python?

I tried this:

app_ui = ui.page_fluid(
                ui.output_text("the_txt")
            )

def server(input, output, session):
    @render.text
    def the_txt():
        url = 'https://stackoverflow.com'
        clickable_url = f'<a> href="{url}" target="_blank">Click here</a>'
        return ui.HTML(clickable_url)

But the displayed text is the raw HTML: <a> href="https://stackoverflow.com" target="_blank">Click here</a>

How do I display a clickable link in a Shiny for Python app?

In your app you have a small syntax error within the tag, you need <a ...> instead of <a> .... Below are two variants, depending on a static case or a situation where you have to render something.

Static case

You don't need a render function here since this is only HTML. Below are two alternatives: Either use ui.tags for creating an a tag or use ui.HTML for passing the HTML directly:

from shiny import ui, App

url = 'https://stackoverflow.com'

app_ui = ui.page_fluid(
    ui.tags.a("Click here",
              href=url,
              target='_blank'),
    ui.p(),
    ui.HTML(f'<a href="{url}" target="_blank">Click here</a>')
)

def server(input, output, session):
    return

app=App(app_ui, server)

Dynamic case

Here is an example where we have an input and render a link dynamically into a text. The output here is set by ui.output_ui and contains a div with the text and the url.

from shiny import ui, App, render, reactive

app_ui = ui.page_fluid(
    ui.input_select("pageSelect",
                    label="Pages",
                    choices=['StackOverflow', 'Google']),
    ui.p(),
    ui.output_ui("text")
)

def server(input, output, session):
    
    @reactive.calc
    def url():
        if (input.pageSelect() == "StackOverflow"):
            url = 'https://stackoverflow.com'
        else: 
            url = 'https://google.com'
        return ui.tags.a("click here", href=url, target='_blank')
    
    @render.ui
    def text(): 
        return ui.div("You can ", 
                      url(), 
                      " for going to ", 
                      input.pageSelect(),
                      ".")

app=App(app_ui, server)