# Stacked Bar Plot In MatPlotLib

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## Preliminaries

```%matplotlib inline
import pandas as pd
import matplotlib.pyplot as plt
import numpy as np
```

## Create dataframe

```raw_data = {'first_name': ['Jason', 'Molly', 'Tina', 'Jake', 'Amy'],
'pre_score': [4, 24, 31, 2, 3],
'mid_score': [25, 94, 57, 62, 70],
'post_score': [5, 43, 23, 23, 51]}
df = pd.DataFrame(raw_data, columns = ['first_name', 'pre_score', 'mid_score', 'post_score'])
df
```
first_name pre_score mid_score post_score
0 Jason 4 25 5
1 Molly 24 94 43
2 Tina 31 57 23
3 Jake 2 62 23
4 Amy 3 70 51

## Make plot

```# Create the general blog and the "subplots" i.e. the bars
f, ax1 = plt.subplots(1, figsize=(10,5))

# Set the bar width
bar_width = 0.75

# positions of the left bar-boundaries
bar_l = [i+1 for i in range(len(df['pre_score']))]

# positions of the x-axis ticks (center of the bars as bar labels)
tick_pos = [i+(bar_width/2) for i in bar_l]

# Create a bar plot, in position bar_1
ax1.bar(bar_l,
# using the pre_score data
df['pre_score'],
# set the width
width=bar_width,
# with the label pre score
label='Pre Score',
# with alpha 0.5
alpha=0.5,
# with color
color='#F4561D')

# Create a bar plot, in position bar_1
ax1.bar(bar_l,
# using the mid_score data
df['mid_score'],
# set the width
width=bar_width,
# with pre_score on the bottom
bottom=df['pre_score'],
# with the label mid score
label='Mid Score',
# with alpha 0.5
alpha=0.5,
# with color
color='#F1911E')

# Create a bar plot, in position bar_1
ax1.bar(bar_l,
# using the post_score data
df['post_score'],
# set the width
width=bar_width,
# with pre_score and mid_score on the bottom
bottom=[i+j for i,j in zip(df['pre_score'],df['mid_score'])],
# with the label post score
label='Post Score',
# with alpha 0.5
alpha=0.5,
# with color
color='#F1BD1A')

# set the x ticks with names
plt.xticks(tick_pos, df['first_name'])

# Set the label and legends
ax1.set_ylabel("Total Score")
ax1.set_xlabel("Test Subject")
plt.legend(loc='upper left')

# Set a buffer around the edge
plt.xlim([min(tick_pos)-bar_width, max(tick_pos)+bar_width])
```
```(0.625, 6.125)
```