January 2018
Intermediate to advanced
856 pages
17h 17m
Chinese
Content preview from Python 技術手冊 第三版
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第 6 章 模組
變更在那個 subshell 終止時就會遺失。對於 bash 與類似的 shells，你會以
下列命令來啟用位於路徑
envpath
的一個環境：
source envpath/bin/activate
其他 shells 的使用者則改用位於相同目錄的
activate.csh
與
activate.fsh
指令
稿。在 Windows 系統上，使用
activate.bat
：
envpath/Scripts/activate.bat
啟用過程會做幾件事，最重要的有：
• 把 virtualenv 的
bin
目錄放到 shell 的
PATH
環境變數的開頭，所以它的
命令才會在
PATH
中已經存在的同名命令之前優先被執行
• 定義一個
deactivate
命令來移除啟用動作所產生的所有效應，並將
Python 環境回復到它之前的狀態
• 修改 shell 的命令提示（prompt）， 將 virtualenv 的名稱納入到其開頭
• 定義一個
VIRTUAL_ENV
環境變數作為 virtualenv 根目錄的路徑（指令稿
可用它來檢視 virtualenv）
這些動作的後果是，只要一個 virtualenv 被啟用，
python
命令就會執行與
那個 virtualenv 關聯的直譯器。該直譯器看得到安裝在那個環境中的程式
庫（模組與套件），而
pip
現在就會是來自 virtualenv 的那個，因為安裝該
模組也會將那個命令安裝在 virtualenv 的
bin
目錄中，所以現在
pip
命令預
設會在該環境的 ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.