Python simple skills and common references_PHP tutorial

Python simple tips and common references

python files support Chinese

# -*- coding: UTF-8 -*-

Execute shell command

from subprocess import Popen, PIPE
def run_cmd(cmd):
#Popen call wrapper.return (code, stdout, stderr)
child = Popen(cmd, stdin = PIPE, stdout = PIPE, stderr = PIPE, shell = True)
Out, err = child.communicate()
ret = child.wait()
Return (ret, out, err)

Get the path of the current python script file

import os
os.path.split(os.path.realpath(__file__))[0]
Problems with json module import

try :
Import json
except :
Import simplejson as json

Use json tool to format json

#python 2.7 or below
echo ＼'{＼"hello＼":1}＼' | python -m simplejson.tool
#python 2.7 and above
echo ＼'{＼"hello＼":1}＼' | python -m json.tool

General calling steps

Py_Initialize(); //Initialize the Python environment
PyImport_ImportModule("test"); // Load python module
PyObject_GetAttrString(g_pModule,"test1"); //Get the PyObject
of the corresponding Python function PyObject_CallFunction(test1,"i,s",2,e); //Call the corresponding function in Python
Py_Finalize(); //End

Sample code in C language

#include
int main(){
PyObject * g_pModule = NULL;
Py_Initialize(); //Before using python, you need to call Py_Initialize(); this function is initialized
If (!Py_IsInitialized())
           {
                         printf("init error＼n");
                    return -1;
}
PyRun_SimpleString("import sys");
PyRun_SimpleString("sys.path.append('./')");
g_pModule =PyImport_ImportModule("mytest");//This is the file name to be called, here is test.py
in the current directory If (!g_pModule) {
                        printf("Cant open python file!＼n");
Return -2;
}
PyObject * test1 = PyObject_GetAttrString(g_pModule,"test1"); //Here is the function name to be called
PyObject *objResult = PyObject_CallFunction(test1,"i,s",2,e);//Call function
          if (!objResult){
​​​​​​printf("invoke function fail＼n");
}

PyObject * test2= PyObject_GetAttrString(g_pModule,"test2"); //Here is the function name to be called
        objResult = PyObject_CallFunction(test2,"i",2);//Call function
char * x = PyString_AsString(objResult);
            printf("%s＼n",x);
Py_Finalize();//Call Py_Finalize, which corresponds to Py_Initialize.
}
Python program mytest.py

def test1(s,str):
Print s+str
Return 0
def test2(s):
Return s

Compilation method of C program

# Assuming that our python is installed in /opt/python when compiling, then we can use such a command to compile the program
$gcc -I/opt/python/include -L/opt/python/lib/ -lpython2.7 test.c
Note: When compiling python, you need to have a dynamic link library and add --enable-shared

./configure --prefix=/opt/python --enable-shared