[c#] How do I run a Python script from C#?

This sort of question has been asked before in varying degrees, but I feel it has not been answered in a concise way and so I ask it again.

I want to run a script in Python. Let's say it's this:

if __name__ == '__main__':
    with open(sys.argv[1], 'r') as f:
        s = f.read()
    print s

Which gets a file location, reads it, then prints its contents. Not so complicated.

Okay, so how do I run this in C#?

This is what I have now:

    private void run_cmd(string cmd, string args)
    {
        ProcessStartInfo start = new ProcessStartInfo();
        start.FileName = cmd;
        start.Arguments = args;
        start.UseShellExecute = false;
        start.RedirectStandardOutput = true;
        using (Process process = Process.Start(start))
        {
            using (StreamReader reader = process.StandardOutput)
            {
                string result = reader.ReadToEnd();
                Console.Write(result);
            }
        }
    }

When I pass the code.py location as cmd and the filename location as args it doesn't work. I was told I should pass python.exe as the cmd, and then code.py filename as the args.

I have been looking for a while now and can only find people suggesting to use IronPython or such. But there must be a way to call a Python script from C#.

Some clarification:

I need to run it from C#, I need to capture the output, and I can't use IronPython or anything else. Whatever hack you have will be fine.

P.S.: The actual Python code I'm running is much more complex than this, and it returns output which I need in C#, and the C# code will be constantly calling the Python code.

Pretend this is my code:

    private void get_vals()
    {
        for (int i = 0; i < 100; i++)
        {
            run_cmd("code.py", i);
        }
    }

If you're willing to use IronPython, you can execute scripts directly in C#:

using IronPython.Hosting;
using Microsoft.Scripting.Hosting;

private static void doPython()
{
    ScriptEngine engine = Python.CreateEngine();
    engine.ExecuteFile(@"test.py");
}

Get IronPython here.

Set WorkingDirectory or specify the full path of the python script in the Argument

ProcessStartInfo start = new ProcessStartInfo();
start.FileName = "C:\\Python27\\python.exe";
//start.WorkingDirectory = @"D:\script";
start.Arguments = string.Format("D:\\script\\test.py -a {0} -b {1} ", "some param", "some other param");
start.UseShellExecute = false;
start.RedirectStandardOutput = true;
using (Process process = Process.Start(start))
{
    using (StreamReader reader = process.StandardOutput)
    {
        string result = reader.ReadToEnd();
        Console.Write(result);
    }
}

Actually its pretty easy to make integration between Csharp (VS) and Python with IronPython. It's not that much complex... As Chris Dunaway already said in answer section I started to build this inegration for my own project. N its pretty simple. Just follow these steps N you will get your results.

step 1 : Open VS and create new empty ConsoleApp project.

step 2 : Go to tools --> NuGet Package Manager --> Package Manager Console.

step 3 : After this open this link in your browser and copy the NuGet Command. Link: https://www.nuget.org/packages/IronPython/2.7.9

step 4 : After opening the above link copy the PM>Install-Package IronPython -Version 2.7.9 command and paste it in NuGet Console in VS. It will install the supportive packages.

step 5 : This is my code that I have used to run a .py file stored in my Python.exe directory.

using IronPython.Hosting;//for DLHE
using Microsoft.Scripting.Hosting;//provides scripting abilities comparable to batch files
using System;
using System.Diagnostics;
using System.IO;
using System.Net;
using System.Net.Sockets;
class Hi
{
private static void Main(string []args)
{
Process process = new Process(); //to make a process call
ScriptEngine engine = Python.CreateEngine(); //For Engine to initiate the script
engine.ExecuteFile(@"C:\Users\daulmalik\AppData\Local\Programs\Python\Python37\p1.py");//Path of my .py file that I would like to see running in console after running my .cs file from VS.//process.StandardInput.Flush();
process.StandardInput.Close();//to close
process.WaitForExit();//to hold the process i.e. cmd screen as output
}
} 

step 6 : save and execute the code

I ran into the same problem and Master Morality's answer didn't do it for me. The following, which is based on the previous answer, worked:

private void run_cmd(string cmd, string args)
{
 ProcessStartInfo start = new ProcessStartInfo();
 start.FileName = cmd;//cmd is full path to python.exe
 start.Arguments = args;//args is path to .py file and any cmd line args
 start.UseShellExecute = false;
 start.RedirectStandardOutput = true;
 using(Process process = Process.Start(start))
 {
     using(StreamReader reader = process.StandardOutput)
     {
         string result = reader.ReadToEnd();
         Console.Write(result);
     }
 }
}

As an example, cmd would be @C:/Python26/python.exe and args would be C://Python26//test.py 100 if you wanted to execute test.py with cmd line argument 100. Note that the path the .py file does not have the @ symbol.

Just also to draw your attention to this:

https://code.msdn.microsoft.com/windowsdesktop/C-and-Python-interprocess-171378ee

It works great.

I am having problems with stdin/stout - when payload size exceeds several kilobytes it hangs. I need to call Python functions not only with some short arguments, but with a custom payload that could be big.

A while ago, I wrote a virtual actor library that allows to distribute task on different machines via Redis. To call Python code, I added functionality to listen for messages from Python, process them and return results back to .NET. Here is a brief description of how it works.

It works on a single machine as well, but requires a Redis instance. Redis adds some reliability guarantees - payload is stored until a worked acknowledges completion. If a worked dies, the payload is returned to a job queue and then is reprocessed by another worker.

Execute Python script from C

Create a C# project and write the following code.

using System;
using System.Diagnostics;
using System.IO;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            run_cmd();
        }

        private void run_cmd()
        {

            string fileName = @"C:\sample_script.py";

            Process p = new Process();
            p.StartInfo = new ProcessStartInfo(@"C:\Python27\python.exe", fileName)
            {
                RedirectStandardOutput = true,
                UseShellExecute = false,
                CreateNoWindow = true
            };
            p.Start();

            string output = p.StandardOutput.ReadToEnd();
            p.WaitForExit();

            Console.WriteLine(output);

            Console.ReadLine();

        }
    }
}

Python sample_script

print "Python C# Test"

You will see the 'Python C# Test' in the console of C#.