importError: No module named site
Python 環境變數
下面幾個重要的環境變數，它應用於Python：
| 變數名 | 描述 |
|---|---|
| PYTHONPATH | PYTHONPATH是Python搜尋路徑，預設我們import的模組都會從PYTHONPATH裡面尋找。 |
| PYTHONSTARTUP | Python啟動後，先尋找PYTHONSTARTUP環境變數，然後執行此變數指定的檔案中的程式碼。 |
| PYTHONCASEOK | 加入PYTHONCASEOK的環境變數, 就會使python匯入模組的時候不區分大小寫. |
| PYTHONHOME | 另一種模組搜尋路徑。它通常內嵌於的PYTHONSTARTUP或PYTHONPATH目錄中，使得兩個模組庫更容易切換。 |
通常我們會在命令列上設定PYTHONPATH。在執行指令碼之前先執行設定PYTHONPATH的命令。
例如windows上，設定PYTHONPATH的命令為：
- SET ROOT_DIR=%~dp0
- SET PYTHONPATH=%PYTHONPATH%;%ROOT_DIR%src\main\python;%ROOT_DIR%src\test\python;%ROOT_DIR%generated\pyxb;%ROOT_DIR%
You know what has worked for me really well on windows.
My
Computer > Properties > Advanced System Settings > Environment Variables >
Then under system variables I create a new Variable called PythonPath.
In this variable I have C:\Python27\Lib;C:\Python27\DLLs;C:\Python27\Lib\lib-tk;C:\other-folders-on-the-path
This is the best way that has worked for me which I hadn't found in any of the docs offered.
EDIT: For those who are not able to get it, Please add
C:\Python27;
along with it. Else it will never work.
今天在除錯Evernote
SDK時， 遇到PythonPath的問題。 查了很多資料，有說用系統環境變數新增PythonPath， 有說在登錄檔中的PythonPath新增新Default欄位， 但是對於我來說都沒有效果， 很奇怪。
最後還是在程式碼裡顯式新增sys.path才好用：
import sys
import hashlib
import binascii
import time
if "..\\lib" not in sys.path:
sys.path.append(r"..\\lib")
Windows 7 Professional I Modified @mongoose_za's answer to make it easier to change the python version:
- [Right Click]Computer > Properties >Advanced System Settings > Environment Variables
- Click [New] under "System Variable"
-
Variable Name: PY_HOME, Variable Value:C:\path\to\python\version
- Click [OK]
- Locate the "Path" System variable and click [Edit]
-
Add the following to the existing variable:
%PY_HOME%;%PY_HOME%\Lib;%PY_HOME%\DLLs;%PY_HOME%\Lib\lib-tk;
-
Click [OK] to close all of the windows.
As a final sanity check open a command prompt and enter python. You should see
>python [whatever version you are using]
If you need to switch between versions, you only need to modify the PY_HOME variable to point to the proper directory. This is bit easier to manage if you need multiple python versions installed.