[FIXED] Matplotlib not rectifying bar color

Issue

I have to create a program that calculate the average value for every rows in column 'total_revenue' and that works, now that I have to plot the minimum of the average value and the max of the average value where the min value had to be red while the max value have to green, main problem is when I plotted them the result for both bar graph are red in red color, take a look at the code:

import pandas as pd 
import matplotlib.pyplot as plt 

data = pd.read_excel("C:\\users\\USER\\Documents\\dataset_file\\ad_table.xlsx",'ad_table')

data['avg_rev'] = data['total_revenue'].apply(lambda r: r/2)

min_avg_rev = data['avg_rev'].min()
max_avg_rev = data['avg_rev'].max()
best_ad = data[data['avg_rev'] == max_avg_rev]
worst_ad = data[data['avg_rev'] == min_avg_rev]

t0 = best_ad[['ad','avg_rev']].values
t1 = worst_ad[['ad','avg_rev']].values

result = pd.DataFrame({t0[0][0]: [t0[0][-1]],t1[0][0]: [t1[0][-1]]})
result = result.rename({0: 'avg_rev'})

plt.style.use('ggplot')

fig = plt.figure()
fig.set_figwidth(9)
fig.set_figheight(5)

col_val = []
for i in data['avg_rev']:
    if i == max_avg_rev:
        col_val.append('green')
    elif i < max_avg_rev:
        col_val.append('red')

plt.bar(t0[:,0],t0[:,-1],width=.5,color=col_val)
plt.bar(t1[:,0],t1[:,-1],width=.5,color=col_val)
plt.title('Result')
plt.xlabel('Group Name')
plt.ylabel('Avg. Revenue')
plt.show()

The dataframe of 'result':

        ad_group_13     ad_group_23
avg_rev 19811.855       -100.075

The plotted graph:

Solution

The issue with colors appears to be in the plt.bar(), where you are calling color=col_val which is an array with 2 items, red and green. So, you should be calling col_val[0] and col_val[1], so that the right color shows up.

Based on available data, I have simplified/modified your code to show the same below.

Code

avg_rev = pd.DataFrame({'ad_group_13' : [19811.855], 'ad_group_23' : [-100.075]})
plt.style.use('ggplot')

fig = plt.figure()
fig.set_figwidth(9)
fig.set_figheight(5)

col_val = ['green', 'red']

plt.bar(avg_rev.columns[0],avg_rev.iloc[0,0],width=.5,color=col_val[0])
plt.bar(avg_rev.columns[1],avg_rev.iloc[0,1],width=.5,color=col_val[1])
plt.title('Result')
plt.xlabel('Group Name')
plt.ylabel('Avg. Revenue')
plt.show()

Output plot

Answered By - Redox