使用pip安装Python模块

Question

我正在尝试安装一个名为Scrapy的模块。我是用电脑安装的

pip install Scrapy

我在my/usr/local/lib/python2中看到了“scrapy”文件夹。7/site包，但当我尝试在Python程序中导入它时，它说没有这个名称的模块。你知道为什么会这样吗？

编辑：以下是pip命令的输出：

    Downloading/unpacking Scrapy
  Downloading Scrapy-0.20.0.tar.gz (745kB): 745kB downloaded
  Running setup.py egg_info for package Scrapy

    no previously-included directories found matching 'docs/build'
Requirement already satisfied (use --upgrade to upgrade): Twisted>=10.0.0 in /usr/local/lib/python2.7/site-packages (from Scrapy)
Requirement already satisfied (use --upgrade to upgrade): w3lib>=1.2 in /usr/local/lib/python2.7/site-packages (from Scrapy)
Requirement already satisfied (use --upgrade to upgrade): queuelib in /usr/local/lib/python2.7/site-packages (from Scrapy)
Requirement already satisfied (use --upgrade to upgrade): lxml in /usr/local/lib/python2.7/site-packages (from Scrapy)
Requirement already satisfied (use --upgrade to upgrade): pyOpenSSL in /usr/local/lib/python2.7/site-packages (from Scrapy)
Requirement already satisfied (use --upgrade to upgrade): cssselect>=0.9 in /usr/local/lib/python2.7/site-packages (from Scrapy)
Requirement already satisfied (use --upgrade to upgrade): zope.interface>=3.6.0 in /usr/local/lib/python2.7/site-packages (from Twisted>=10.0.0->Scrapy)
Requirement already satisfied (use --upgrade to upgrade): six>=1.4.1 in /usr/local/lib/python2.7/site-packages (from w3lib>=1.2->Scrapy)
Requirement already satisfied (use --upgrade to upgrade): setuptools in /usr/local/lib/python2.7/site-packages/setuptools-1.1.6-py2.7.egg (from zope.interface>=3.6.0->Twisted>=10.0.0->Scrapy)
Installing collected packages: Scrapy
  Running setup.py install for Scrapy
    changing mode of build/scripts-2.7/scrapy from 644 to 755

    no previously-included directories found matching 'docs/build'
    changing mode of /usr/local/bin/scrapy to 755
Successfully installed Scrapy
Cleaning up...

当我运行 /usr/local/bin/scrapy我得到命令和可用命令的用法。我注意到我的 /usr/local/bin中有一个python2.7和python2.7-32，我记得因为小牛的问题安装了32位版本。

下面是python/usr/local/bin/scrapy的输出：

Traceback (most recent call last): File "/usr/local/bin/scrapy", line 3, in <module> from scrapy.cmdline import execute ImportError: No module named scrapy.cmdline 

和head/usr/local/bin/scrapy：

#!/usr/local/opt/python/bin/python2.7 from scrapy.cmdline import execute execute()

Answer 1

当所有其他操作都失败时，您可以始终将环境变量PYTHONPATH（请参阅将目录永久添加到PYTHONPATH以获取帮助）设置为安装Scrapy的路径。（如果您不使用virtualenv，请详细说明，以便我们提供帮助，一般来说，提供操作系统也是一个好主意）

Answer 2

编辑：您可以强制pip安装到其他位置。详细信息如下：使用pip？将Python包安装到不同的目录中？。如果您的系统上确实有额外的Python文件夹，也许您可以尝试将scrapy定向到这些文件夹，即使只是为了一个临时解决方案。

您可以发布pip命令的输出吗？也许它在某个地方失败了？

另外，您的机器上是否可能有两个版本的Python？Pip只安装到一个位置，但路径上的Python版本可能不同。

最后，有时给pip的包名与用于导入的包名不完全相同。检查包的文档。我快速查看了一下，导入应该是小写的：

import scrapy

Answer 3

你是在用自制的还是MacPorts什么的？正如@J.F.Sebastian所说，听起来您在混合OSX附带的默认python和通过软件包管理器安装的python时遇到了问题。。。试试/usr/local/opt/python/bin/python2。7-m scrapy并查看是否会抛出一个ImportError。

如果这是可行的，那么你可能想考虑让Python可执行文件是默认的。类似于别名python2。7=/usr/local/opt/python/bin/python2。7然后始终使用python2。7而不是默认的python。同样，您也可以将python指向/urs/local 位，但是如果您出于某种原因需要系统（OSX提供的）python，您将无法轻松访问它。