ipython安装新模块

Question

我习惯了安装包的R功能,我正在尝试用ipython做同样的事情.有时候下面的方法有效,但有时它却没有,我想终于找出为什么它只能工作一半的时间.

通常安装模块(例如ipython模块)我打开一个新终端后会输入以下内容:

$ sudo pip install requests
Password: ******* 

然后会出现一条消息,指示安装已成功完成或已安装.

Requirement already satisfied (use --upgrade to upgrade): 
requests in /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages
Cleaning up... 

这表明可以访问代码.事实上,如果我现在从终端运行python,它会显示出良好的响应,而不会出现任何错误.

$ python
ActivePython 2.7.2.5 (ActiveState Software Inc.) based on
Python 2.7.2 (default, Jun 24 2011, 12:20:15) 
[GCC 4.2.1 (Apple Inc. build 5664)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import requests
>>> 

我现在通过Alfred打开PyLab,它给了我一个错误.

Welcome to pylab, a matplotlib-based Python environment [backend: WXAgg].
For more information, type 'help(pylab)'.

In [1]: import requests
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
/Users/vincentwarmerdam/<ipython-input-1-686486c241c8> in <module>()
----> 1 import requests

ImportError: No module named requests

我从stackoverflow上的另一个问题(这里是http://bit.ly/1148FRL)上看到了一些帮助,它建议我从ipython shell安装模块.这给出了更令人费解的反应:

In [2]: !pip install requests
Requirement already satisfied (use --upgrade to upgrade): requests in     
/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages
Cleaning up...

In [3]: import requests
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
/Users/vincentwarmerdam/<ipython-input-3-686486c241c8> in <module>()
----> 1 import requests

ImportError: No module named requests

这对我来说似乎很奇怪.系统上是否安装了多个版本的python？我怎么检查这个？我是否需要将ipython指向已安装代码的位置？

Answer 1

实际上有一个更优雅的解决方案.当安装pip然后在python中你也可以做这样的事情:

import pip

def install(package):
   pip.main(['install', package])

install('requests') 

这更容易.一旦登录了virtualenv,您就可以确保在您所在的会话中拥有所需的内容.

编辑

另一种选择是使用%%bash魔法.

%%bash
pip install requests

EDIT2

如果你想要标准输出,甚至可以使用感叹号.

! pip install requests

Answer 2

这就是我所做的让它发挥作用的东西; 通过命令行打开iypthon并输入

import sys
sys.path 

这显示了其他python模块所在的文件夹列表.对我来说这是:

['',
 '/Library/Frameworks/Python.framework/Versions/7.3/bin',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/pandas-0.10.0-py2.7-macosx-10.5-i386.egg',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/googlemaps-1.0.2-py2.7.egg',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/oauth-1.0.1-py2.7.egg',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/oauth2-1.5.211-py2.7.egg',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/httplib2-0.7.7-py2.7.egg',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/selenium-2.28.0-py2.7.egg',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/jellyfish-0.2.0-py2.7-macosx-10.5-i386.egg',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/python_yelp-0.1.1-py2.7.egg',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/pymongo-2.4.2_-py2.7-macosx-10.5-i386.egg',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/lucene_querybuilder-0.1.6-py2.7.egg',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/mechanize-0.2.5-py2.7.egg',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/html2text-3.200.3-py2.7.egg',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python27.zip',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/plat-darwin',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/plat-mac',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/plat-mac/lib-scriptpackages',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/lib-tk',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/lib-old',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/lib-dynload',
 '/Users/vincentwarmerdam/Library/Python/2.7/lib/python/site-packages',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/PIL',
 '/Library/Python/2.7/site-packages',
 '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/IPython/extensions] 

有了这些信息,我现在知道ipython在哪里查找可以导入的模块.所以我手动下载了请求库,将其添加到同一个根目录,以便存在以下目录:

/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/site-packages/requests 

该文件夹包含属于请求的python模块.我现在唯一要做的就是确保ipython知道这个文件夹存在.这是通过更新sys.path完成的.

req_link = '/Library/Frameworks/Python.framework/Versions/7.3/lib/python2.7/requests'
sys.path.append(req_link) 

在此之后我不再有错误.

import requests 

只是工作.

在重启ipython之后,我发现ipython会自动将新路径更新到sys.path列表中.