Explicitly set colors in px.line

📊 Plotly Python
1

I’m a little dumbfounded as to why it is so difficult / obscure to explicitly set colors explicitly (as compared with adopting some color map and assuming there is a column in the data that dictates it). What am I missing?

Seem to me that to explicitly set the color to say BLUE = 'rgb(30,144,255)

fig = px.line(plot_data, x='date',y='quantile',color_discrete_map={'dumb':BLUE})

This assumes you have a column ‘dumb’ that is constant.

For scatter there seems to be many ways to do it that seem more sensible (though line_color would seem to be a nice argument to have)

fig.add_scatter(df, x="sepal_width", y="sepal_length", line=dict(color="crimson"))

Or

fig.add_scatter( x=df['date'],y=df["price"],mode='markers',marker_color=BLUE)

2

You can set the mapping to the identity mapping like this:

import plotly.express as px

fig = px.bar(x=["a","b","c"], y=[1,3,2], color=["red", "goldenrod", "#00D"], 
    color_discrete_map="identity")
fig.show()

and you can set the color to be a constant (with the identity mapping) like this:

import plotly.express as px

fig = px.bar(x=["a","b","c"], y=[1,3,2], color=px.Constant("green"), 
    color_discrete_map="identity")
fig.show()
3

Finally, you can always overwrite anything you like with fix.update_traces(line_color="green"), say :slight_smile:

4

So…

px.line(x=["a","b","c"], y=[1,3,2]).update_traces(line_color="green")

is the recommendation for px.line?

5

That works, yep. For a bar chart it’ll be fig.update_traces(marker_color="green") etc etc.

6

You can also do px.line(x=["a","b","c"], y=[1,3,2], color_discrete_sequence=["green"]) come to think of it. Lots of options :slight_smile:

7

I very much appreciate the quick response.