Use MATLAB Compiler SDK to Work with Pandas DataFrames

Supported platforms: Windows®, Linux®, Mac

This example shows how to create a Python® application that passes weather data stored in a Pandas DataFrame from Python to MATLAB®. The MATLAB function finds the maximum humidity in the given weather data. The Python application creates the DataFrame, calls the MATLAB function, and displays the result.

When you pass data between MATLAB and Python, MATLAB Compiler SDK™ converts the data into an equivalent data type. For a complete list of data types and their conversions, see Pass Data Between MATLAB and Python. For a list of data types and their conversions when they are converted within tables or DataFrames, see Convert Between MATLAB tables and Pandas DataFrames.

Prerequisites

Verify that you have a version of Python installed that is compatible with MATLAB Compiler SDK. For details, see MATLAB Compiler SDK Python Target Requirements.

The target machine requires MATLAB Runtime to run the deployed MATLAB code. You can include MATLAB Runtime in an installer for your Python package or install it separately. For details, see Download and Install MATLAB Runtime.

You also need a Python environment with Pandas installed.

Create Function in MATLAB

This MATLAB function takes weather data for the past 24 hours, specified as a pandas.DataFrame, and returns the maximum humidity within that time period. You can use MATLAB Compiler SDK to package the function into a Python module. To do so, first save this function as getMaxHumidity.m.

function max_humidity = getMaxHumidity(weatherData)
% Given a table of data recorded by a weather station over 24 hours, get the max
% humidity.
max_humidity = max(weatherData(:,4));
end

Create Python Package

Build the Python package with the Python Package Compiler app or the compiler.build.pythonPackage function. Package the getMaxHumidity.m file and name the package getMaxHumidityPkg.

For example, if you are using compiler.build.pythonPackage, use this command.

buildResults = compiler.build.pythonPackage( ...
'getMaxHumidity.m', ...
'PackageName','getMaxHumidityPkg');

For details, see the instructions in Generate Python Package and Build Python Application.

Write Python Application Code

Write code in Python for an application named getMaxHumiditySample.py. This sample application creates a pandas.DataFrame with weather data and passes it to the packaged function, which returns the maximum humidity.

#!/usr/bin/env python

import getMaxHumidityPkg

# Import the matlab module only after you have imported
# MATLAB Compiler SDK generated Python modules.
import matlab
import datetime as dt
import pandas as pd

try:
    # Initialize Python module created with MATLAB Compiler SDK.
    my_getMaxHumidityPkg = getMaxHumidityPkg.initialize()
except Exception as e:
    print("Error initializing getMaxHumidityPkg package\\n:{}".format(e))
    exit(1)

try:
    # Create a DataFrame from the data for the past 24 hours.
    data = {
        "Time": [
            dt.datetime.strptime(i, "%Y-%m-%d %H:%M")
            for i in [
                "2024-10-30 18:00",
                "2024-10-30 21:00",
                "2024-10-31 00:00",
                "2024-10-31 03:00",
                "2024-10-31 06:00",
                "2024-10-31 09:00",
                "2024-10-31 12:00",
                "2024-10-31 15:00",
                "2024-10-31 18:00"
            ]
        ],
        "Temperature (°F)": [67, 64, 62, 60, 58, 61, 70, 75, 79],
        "Weather": [
            "Clear",
            "Overcast",
            "Passing clouds",
            "Passing clouds",
            "Passing clouds",
            "Partly sunny",
            "Partly sunny",
            "Passing clouds",
            "Partly sunny"
        ],
        "Wind Speed (mph)": [8, 10, 7, 6, 5, 7, 9, 10, 12],
        "Humidity (%)": [51, 73, 78, 80, 82, 74, 65, 58, 50],
    }

    # Convert data into a DataFrame.
    xIn = pd.DataFrame(data)
    # Call the packaged function.
    yOut = my_getMaxHumidityPkg.getMaxHumidity(xIn)
    print(yOut)
except Exception as e:
    print("Error occurred during program execution\\n:{}".format(e))

my_getMaxHumidityPkg.terminate()

The application performs these steps:

  • Imports the getMaxHumidityPkg, matlab, datetime, and pandas packages.

  • Instantiates the getMaxHumidityPkg instance as my_getMaxHumidityPkg.

  • Creates a dict named data containing 24 hours of weather data and converts it into a Pandas DataFrame.

  • Calls the getMaxHumidity method in the getMaxHumidityPkg package to convert the weather data into a MATLAB table and get the maximum value in the Humidity (%) column.

  • Displays the result.

  • Uses a try block to catch and handle any exceptions.

Install and Run Python Package

On the target machine, install the generated Python package. For more details, see Install and Import MATLAB Compiler SDK Python Packages.

In the system command prompt, navigate to the folder containing the generated files and install the Python package.

python -m pip install .

Run the application.

python getMaxHumidityPkg.py

The application generates this output.

    Humidity___
0           82

See Also

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