安裝BeautifulSoup時出錯

Question

這裏我的問題有兩點。我試圖安裝BeautifulSoup，但面臨以下錯誤：

Rahul-MacBook-Air:~ rahul$ sudo easy_install pip 
Password: 
Searching for pip 
Best match: pip 8.1.2 
Processing pip-8.1.2-py2.7.egg 
pip 8.1.2 is already the active version in easy-install.pth 
Installing pip script to /usr/local/bin 
Installing pip2.7 script to /usr/local/bin 
Installing pip2 script to /usr/local/bin 

Using /Library/Python/2.7/site-packages/pip-8.1.2-py2.7.egg 
Processing dependencies for pip 
Finished processing dependencies for pip 

Rahul-MacBook-Air:~ rahul$ pip install beautifulsoup4 
Collecting beautifulsoup4 
    Using cached beautifulsoup4-4.5.1-py2-none-any.whl 
Installing collected packages: beautifulsoup4 
Exception: 
Traceback (most recent call last): 
    File "/Library/Python/2.7/site-packages/pip-8.1.2-py2.7.egg/pip/basecommand.py", line 215, in main 
    status = self.run(options, args) 
    File "/Library/Python/2.7/site-packages/pip-8.1.2-py2.7.egg/pip/commands/install.py", line 317, in run 
    prefix=options.prefix_path, 
    File "/Library/Python/2.7/site-packages/pip-8.1.2-py2.7.egg/pip/req/req_set.py", line 742, in install 
    **kwargs 
    File "/Library/Python/2.7/site-packages/pip-8.1.2-py2.7.egg/pip/req/req_install.py", line 831, in install 
    self.move_wheel_files(self.source_dir, root=root, prefix=prefix) 
    File "/Library/Python/2.7/site-packages/pip-8.1.2-py2.7.egg/pip/req/req_install.py", line 1032, in move_wheel_files 
    isolated=self.isolated, 
    File "/Library/Python/2.7/site-packages/pip-8.1.2-py2.7.egg/pip/wheel.py", line 346, in move_wheel_files 
    clobber(source, lib_dir, True) 
    File "/Library/Python/2.7/site-packages/pip-8.1.2-py2.7.egg/pip/wheel.py", line 317, in clobber 
    ensure_dir(destdir) 
    File "/Library/Python/2.7/site-packages/pip-8.1.2-py2.7.egg/pip/utils/__init__.py", line 83, in ensure_dir 
    os.makedirs(path) 
    File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/os.py", line 157, in makedirs 
    mkdir(name, mode) 
OSError: [Errno 13] Permission denied: '/Library/Python/2.7/site-packages/beautifulsoup4-4.5.1.dist-info' 

有人可以告訴我我在做什麼錯在這裏？

我的下一個問題與前一個問題有關。我已經安裝了Python 3.5.2

>>> print(sys.version) 
3.5.2 (v3.5.2:4def2a2901a5, Jun 26 2016, 10:47:25) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] 
>>> 

但是在終端上就說明我一個不同的版本：

​​

所以，當我嘗試安裝BeautifulSoup它開始指向到Python 2.7，我認爲是錯誤的。它應該指向最新的Python版本，即3.5.2

另外，我已經預裝了Python 2.7，編號爲/usr/bin/python，Python 3.5.2安裝在/usr/local/bin/python。 如何默認Python版本，使得每次我打開我的終端時它已經指向的Python 3.5.2

感謝， 拉胡爾

Answer 1

你可以選擇安裝BeautifulSoup因爲用戶你正在運行費神下的命令沒有足夠的權限來訪問系統目錄。嘗試用sudo運行命令：

sudo pip install beautifulsoup4 

接下來，你說你已經安裝了Python 3.5.2，但沒有顯示你正在使用運行它的命令。我很確定這是類似於python3（無論如何，而不是只是python），所以什麼讓你想知道爲什麼python -V顯示不同的版本號？命令python運行不同的Python解釋器。

如果你想爲Python 3.5安裝任何東西，你需要pip3而不是pip。

您可以使python作爲python3.5的別名（或符號鏈接），並且可能會將Python 2.7解釋器重命名爲python2.7之類的名稱（如果尚未完成）。