Feature request: Simple API for lines+markers in Plotly express

[malmaud]

Thanks for the great work on Plotly express!

I think it would be nice to have a concise express function to plot a line chart with markers shown. This can be done now with

fig=express.line(...)
fig.update_traces(mode='markers+lines') 

but that seems quite verbose for a fairly common kind of figure. What about, for example, adding a keyword argument to express.line to specify marker properties?

cf matplotlib, where you can conveniently do this with something like plt.plot(x, y, fmt='.-') to get line plot with markers.

[nicolaskruchten]

I've also found it annoying to reach for update_traces just to turn markers on! I don't think we'll do something as terse as fmt as shown but we should do something, indeed.

I'm torn between a single markers=True or a more full-blow symbol="column" type option. With the latter, just turning markers on would be symbol=px.Constant(True) or something like that.

[nicolaskruchten]

I'm torn between a single markers=True or a more full-blow symbol="column" type option.

I implemented both in #3326 :)