Mady•8mo ago

Altair label conditional color

Does anyone know how to conditionally color an Altair chart label based on the value of another column? Struggling to find this one on Google

22 Replies

Myles Scolnick•8mo ago

are you using mark_text()? Maybe something like:

encode(
  ....
  color=alt.condition(
        alt.datum.highlight,  # Condition based on the 'highlight' column
        alt.value('red'),     # Color if condition is true
        alt.value('black')    # Color if condition is false
    )

encode(
  ....
  color=alt.condition(
        alt.datum.highlight,  # Condition based on the 'highlight' column
        alt.value('red'),     # Color if condition is true
        alt.value('black')    # Color if condition is false
    )

MadyOP•8mo ago

I'm not, just a fairly basic chart. I'm just trying to change the color of the axis labels. This is what I'm doing and it's not throwing an error but the conditional isn't working as expected

MadyOP•8mo ago

I'm also doing a conditional sort based on a checkbox that isn't working I don't know why I can't get any conditionals to work right with this chart 🤦🏼‍♀️

Myles Scolnick•8mo ago

are you using mo.ui.altair_chart , if so, can you try without it? we add some of our own conditions and not sure if they are conflicting is the axis at least green or red? or its neither color?

MadyOP•8mo ago

it's red, so it is responding, just not correctly

Myles Scolnick•8mo ago

if you flip to alt.datum.Climbed < 0.1 does the color flip?

MadyOP•8mo ago

it does not I also tried removing mo.ui.altair_chart and it didn't change

Myles Scolnick•8mo ago

if you mis-spell Climbed , does it error?

MadyOP•8mo ago

it's like it's not correctly referencing the Climbed field but I'm not sure what else to try to reference it no, it doesn't

Myles Scolnick•8mo ago

i wonder if that field is somehow being dropped. maybe its the fold? if you return avg_stacked_bar , do you see Climbed in the dataframe?

MadyOP•8mo ago

avg_stacked_bar is the chart itself. I'm not sure how to pull out the dataframe itself after the fold

Myles Scolnick•8mo ago

sorry avg_stacked_bar.data

MadyOP•8mo ago

it's there...

Myles Scolnick•8mo ago

can you try alt.datum.Climbed == "0.2" in case its being converted to a string

MadyOP•8mo ago

all red still I got this one fixed and the issue was unrelated

MadyOP•8mo ago

I also tried simplifying down the chart and adding parenthesis to the logic to make sure it was evaluating in the correct order with no change in behavior

Myles Scolnick•8mo ago

nothing looks wrong to me there. im pretty stumped. if i had to guess - maybe lableColor isnt conditionally colorable

MadyOP•8mo ago

I am confident that you can, because there are StackOverflow posts about it, and it is doing something, it's just not evaluating the conditional correctly.

Stack Overflow

Changing the color of the chart label axis

My visualization: I have made the above visualization with altair and would like to know if it is possible to add other colors to the labels like I did with hook, that matches the color of the leg...

MadyOP•8mo ago

I also tried using the same conditional on another property and am having the same issue

MadyOP•8mo ago

I just did a dumb experiment to make sure that the conditional worked in general and it does. it's specifically something with the Climbed comparison

MadyOP•8mo ago

I finally got it to work how I wanted it to by iterating through the dataframe to check for the condition, creating a list of labels that satisfy the condition, then making that the conditional. Still no success just directly doing the conditional in the chart good enough for me though, it works

Myles Scolnick•8mo ago

ah that is a smart workaround! glad you figured it out