Format Barcharts

📊 Plotly Python
1

I have a barchart for values for each date. Now I am looking for a way to change the bars color depending on the value of the previous date: like, if it is lower color= red, if it is higher color=red.

2

To change bar colors in a Plotly bar chart based on comparisons with the previous date’s value, you can use conditional logic in Python. Here’s a basic outline:

  1. Loop through the data points and compare each value to the previous date’s value.
  2. Set the bar color to red if the current value is lower or higher than the previous value.

Here’s an example using Plotly in Python:

python

Copy code

import plotly.graph_objects as go

values = [100, 95, 110, 80, 115]
dates = ['2024-10-01', '2024-10-02', '2024-10-03', '2024-10-04', '2024-10-05']
colors = []

for i in range(len(values)):
    if i == 0:
        colors.append('blue')  # No previous date for first value
    elif values[i] > values[i - 1]:
        colors.append('green')  # Higher value than previous
    else:
        colors.append('red')  # Lower value than previous

fig = go.Figure([go.Bar(x=dates, y=values, marker_color=colors)])
fig.show()

In this example, the bar will be colored red if the value is lower than the previous day, green if it’s higher, and blue for the first bar (as no comparison is possible).

3

Thanks! Code shown below looks great, but I am using javascript to design the plot. I will try to use your idea to change the code accordingly.