CODEWITHSUNDEEP
pythonmatplotlib
programminglearner
programminglearner

Reputation: 542

Changing chart column color based off data

I have a python script that parses a csv file and creates a mixed chart from it.

If the Current Progress has dropped since the Previous Progress by more than 5, I would like to change the color of the CurrentProg bar to red. Is it possible to do this?

For example, the table below is a sample of the csv file that I am parsing. I would like CurrentProg bar for Derick and Lisa to be red as shown in the graph below it.

Name               OldProg               PrevProg               CurrentProg              Goal
Derick                 45                             60                           52                      90
Jenna                 56                             87                           89                      90
Lisa                    78                             93                           76                      90
Harry                  98                             84                           79                      90

enter image description here

Here is a snippet of the code that parses the csv file and puts them into a bars/lines for the chart. 

import pandas as pd
import matplotlib.pyplot as plt
import numpy as np

df = pd.read_csv("file.csv")
names = df['name'].values
x = np.arange(len(names))*2
w = 0.40
plt.bar(x-w, df['Old Progress'].values, width=w*0.7, label='OldProg', color = "cyan")
plt.bar(x, df['Previous Progress'].values, width=w*0.7, label='PrevProg', color = "green")
plt.bar(x+w, df['Current Progress'].values, width=w*0.7, label='CurrentProg', color = "blue")
plt.plot(x, df['Goal'].values, lw=2, label='Goal', color = "red")

Please let me know if I need to clarify anything further. Thank you.

Upvotes: 0

Views: 153

Answers (1)

I.Ped
I.Ped

Reputation: 108

plt.bar() can accept a list of colors with the same length as the number of items in the bar plot, rather than just a single color.

Thus, you can calculate the colors for each element in the bar plot, and pass that as the colors parameter.

Something like this shoould do the trick:

df = pd.read_csv('test.csv')
progress_difference = df['CurrentProg'] - df['PrevProg']
colors = ['Red' if d < -5 else 'Grey' for d in progress_difference]
...
plt.bar(x+w, df['CurrentProg'].values, width=w*0.7, 
        label='CurrentProg', color = colors)

Upvotes: 1

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