Pie Chart Diagrams

Pie charts are used to display data distribution and proportions. The PieChart class allows you to create simple, visual representations of data as percentages of a whole.

Overview

A Pie Chart divides a circle into slices, where each slice represents a proportion of the total. It's useful for showing how different categories make up a whole, like budget allocation, market share, or survey responses.

Basic Usage

Creating a Simple Pie Chart

from mermaid import Mermaid
from mermaid.piechart import PieChart
 
# Create data
data = {
    "Python": 30,
    "JavaScript": 25,
    "Java": 20,
    "Go": 15,
    "Rust": 10
}
 
# Create pie chart
pie = PieChart(
    title="Programming Languages Usage",
    data=data
)
 
Mermaid(pie)

PieChart Class

Constructor

PieChart(
    title: str,
    data: dict[str, float],
    show_data: bool = False,
    config: Optional[Config] = None
)

Parameters

title (str): The chart title
data (dict[str, float]): Dictionary with labels as keys and values as numbers
show_data (bool): Whether to display data values on the chart. Default: False
config (Optional[Config]): Configuration settings

Data Format

The data parameter should be a dictionary where:

Keys (str): Category labels
Values (float): Numeric values (will be converted to percentages)

data = {
    "Category A": 100,
    "Category B": 50,
    "Category C": 25,
    "Category D": 25
}
# Results in: A=50%, B=25%, C=12.5%, D=12.5%

Examples

Budget Allocation

from mermaid import Mermaid
from mermaid.piechart import PieChart
 
budget = {
    "Development": 40,
    "Testing": 20,
    "Documentation": 15,
    "DevOps": 15,
    "Management": 10
}
 
pie = PieChart(
    title="Project Budget Allocation",
    data=budget,
    show_data=True
)
 
Mermaid(pie)

Customer Satisfaction

satisfaction = {
    "Very Satisfied": 45,
    "Satisfied": 35,
    "Neutral": 12,
    "Dissatisfied": 6,
    "Very Dissatisfied": 2
}
 
pie = PieChart(
    title="Customer Satisfaction Survey",
    data=satisfaction,
    show_data=True
)

Market Share

market_share = {
    "Company A": 2500,
    "Company B": 1800,
    "Company C": 1200,
    "Company D": 950,
    "Others": 550
}
 
pie = PieChart(
    title="Current Market Share",
    data=market_share
)

Technology Stack Usage

tech_stack = {
    "React": 35,
    "Vue": 25,
    "Angular": 20,
    "Svelte": 12,
    "Others": 8
}
 
pie = PieChart(
    title="Frontend Framework Usage",
    data=tech_stack,
    show_data=True
)

Display Data

Set show_data=True to display the actual values or percentages:

# Without data values (default)
pie1 = PieChart(title="Chart 1", data=data, show_data=False)
 
# With data values displayed
pie2 = PieChart(title="Chart 2", data=data, show_data=True)

Saving Pie Charts

pie = PieChart(title="My Chart", data={"A": 30, "B": 70})
 
# Save as SVG
pie.save("chart.mmd")

Tips

Use meaningful category names that are self-explanatory
Limit to 5-7 categories for clarity
Ensure all values sum to a meaningful total
Use show_data=True for precise percentages
Order categories by value (largest first) for better readability
Use descriptive titles that explain what's being shown
Consider using other chart types for more than 8 categories

Userjourney Config