python2.7与3.6的区别 python2.7和3.9

1. 系统默认python3.9

那么系统默认，python3.9版本，像wireshark 的插件就是用python3写的。为了方便之后的使用，所以不需要更改这个默认。

但是有的之前程序需要python2.7，这咋整呢？ 

2.vscode 里调用python

这样的话，我们可以选择 python2.7低版本，来运行。

这是lanuch.json 文件,

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [

        {
            "name": "example",
            "type": "python",
            "request": "launch",
            "program": "${file}",
            "console": "integratedTerminal",
            "python": "${command:python.interpreterPath}",
             "args": [
                 "--extcap-interfaces","List available interfaces to capture from"
            ],
            "cwd": "${workspaceFolder}",
        },
        {
            "name": "wvt_gui",
            "type": "python",
            "request": "launch",
            "console": "integratedTerminal",
            "env": {"PYTHONPATH":"${workspaceRoot}"},
            "python.autoComplete.extraPaths": ["./src"],
            "program": "${workspaceFolder}\\tool\\wvt\\src\\wvt_gui.py",
            "args": [
            ],
        }
    ]
}