[FIXED] Populating text on a grid does not place text in the grid cell nor do the cells appear

Issue

I have the following Python code:

import json
import sys
import matplotlib.pyplot as plt
import numpy as np

if len(sys.argv) != 2:
    print("Usage: python script_name.py <path_to_input_json>")
    sys.exit(1)

filename = sys.argv[1]
with open(filename) as f:
  data = json.load(f)

# Set up figure and axes
fig, ax = plt.subplots(figsize=(12, 10)) 

# Set up data for grid
periods = ['early_morning', 'morning', 'noon', 'afternoon', 'evening', 'night', 'late_night']
days = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']
grid_data = np.full((len(periods), len(days)), '', dtype=object)

# Set up axes
ax.set_xticks(np.arange(len(days)))
ax.set_yticks(np.arange(len(periods)))
ax.set_xticklabels(days)
ax.set_yticklabels(periods)

ax.set_title('Weekly Schedule')
ax.set_xlabel('Day of the week')
ax.set_ylabel('Time Periods')

# Rotate x-axis labels to prevent overlap
plt.setp(ax.get_xticklabels(), rotation=45, ha="right",
         rotation_mode="anchor")

# Adjust spacing to prevent label overlap
fig.tight_layout() 

# Populate grid
for i, day in enumerate(days):
  for j, period in enumerate(periods):
    cell_text = []
    if day in data and period in data[day]:
      if data[day][period]['accuracy_level'] >= 0.7:
        for item in data[day][period]['study_material']:
          if item['accuracy_level'] >= 0.7:
             cell_text.append(item['course'])
             cell_text.append(item['subject'])
             if data[day][period]['accuracy_level'] >= 0.7:
                cell_text.append(data[day][period]['platform_group'])
          

    if cell_text: 
        ax.text(j, i, cell_text, ha='center', va='center') 

# Save figure 
plt.savefig('weekly_schedule.png')

It outputs the following result:

Please advise on how a few questions:

1. how to align the text into the proper location on the grid, based on the periods and days values I have from my input data?
2. is it possible to draw the grid lines?
3. is it possible to space 'early_morning' & 'late_night' values on the Y axis and 'Monday' & 'Sunday' on X axis respectively?

Solution

It would be easier to help you if you included a sample of data. That being said. Your code is almost correct. I noticed that you inverted x/y: ax.text(j, i,...) should be ax.text(i, j,.... Also there is no need to check twice if data[day][period]['accuracy_level'] >= 0.7. Displaying cell_text (a list) isn't readable, you could join its element with a line break for instance: '\n'.join(cell_text).

Showing the grid is easy: ax.grid(visible=True).

Finally if you want to add columns left/right and rows on top/bottom, you can specify it in ax.set_xticks and ax.set_xticklabels (and for y resp.). Note that you'll have to change the above mentionned ax.text(i, j,... to ax.text(i+1, j+1,....

I created a little sample to show you the result:

import json
import sys
import matplotlib.pyplot as plt
import numpy as np

data = {
    'Monday': {
        'noon': {
            'accuracy_level': 0.8,
            'study_material': [{
                'accuracy_level': 0.8,
                'course': 'course1',
                'subject': 'subject1'
            }],
            'platform_group': 'PG1'
        },
        'evening': {
            'accuracy_level': 0.8,
            'study_material': [{
                'accuracy_level': 0.8,
                'course': 'course2',
                'subject': 'subject2'
            }],
            'platform_group': 'PG2'
        }
    },
    'Wednesday': {
        'early_morning': {
            'accuracy_level': 0.8,
            'study_material': [{
                'accuracy_level': 0.8,
                'course': 'course3',
                'subject': 'subject3'
            },
            {
                'accuracy_level': 0.8,
                'course': 'course4',
                'subject': 'subject4'
            }],
            'platform_group': 'PG3'
        }
    }
}

# Set up figure and axes
fig, ax = plt.subplots(figsize=(12, 10)) 

# Set up data for grid
periods = ['early_morning', 'morning', 'noon', 'afternoon', 'evening', 'night', 'late_night']
days = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']
grid_data = np.full((len(periods), len(days)), '', dtype=object)

# Set up axes
ax.set_xticks(np.arange(len(days)+2))
ax.set_yticks(np.arange(len(periods)+2))
ax.set_xticklabels([''] + days + [''])
ax.set_yticklabels([''] + periods + [''])
ax.grid(visible=True)

ax.set_title('Weekly Schedule')
ax.set_xlabel('Day of the week')
ax.set_ylabel('Time Periods')

# Rotate x-axis labels to prevent overlap
plt.setp(ax.get_xticklabels(), rotation=45, ha="right",
         rotation_mode="anchor")

# Populate grid
for i, day in enumerate(days):
  for j, period in enumerate(periods):
    cell_text = []
    if day in data and period in data[day]:
      if data[day][period]['accuracy_level'] >= 0.7:
        for item in data[day][period]['study_material']:
          if item['accuracy_level'] >= 0.7:
             cell_text.append(item['course'])
             cell_text.append(item['subject'])
             if data[day][period]['accuracy_level'] >= 0.7:
                cell_text.append(data[day][period]['platform_group'])
          

    if cell_text: 
        ax.text(i+1, j+1, '\n'.join(cell_text), ha='center', va='center') 

plt.show()

Output:

Answered By - Tranbi