我制作了一个模型,并运行了python manage.py syncdb.我认为在db中创建了一个表.然后我意识到我错误地创建了一个列,所以我更改了它,然后运行相同的命令,认为它会丢弃旧表,并添加一个新表.
然后我去了python manage.py shell,并尝试运行.objects.all(),它失败了,说该列不存在.
我想清除旧表,然后再次运行syncdb,但我无法弄清楚如何做到这一点.
我已经开始认识到ElementTree不会按照我的意愿去做.我已经查看了lxml的文档,看来它将满足我的目的.要获得lxml,我需要获得easy_install.所以我从这里下载了它,然后把它放进去/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/.然后我去了那个文件夹,跑了sh setuptools-0.6c11-py2.6.egg.
安装成功.然后我很兴奋,因为我认为easy_install的重点是我可以通过easy_install lxml进行安装,并且lxml会神奇地下载,构建和正确安装,为我的导入享受做好准备.所以我跑了easy_install lxml.我粘贴了下面的结果.我该怎么办？
easy_install lxml
Searching for lxml
Reading http://pypi.python.org/simple/lxml/
Reading http://codespeak.net/lxml
Best match: lxml 2.2.6
Downloading http://codespeak.net/lxml/lxml-2.2.6.tgz
Processing lxml-2.2.6.tgz
Running lxml-2.2.6/setup.py -q bdist_egg --dist-dir /var/folders/49/49N0+g5QFKCm51AbzMtghE+++TI/-Tmp-/easy_install-rxbP6K/lxml-2.2.6/egg-dist-tmp-fjakR0
Building lxml version 2.2.6.
NOTE: Trying to build without Cython, pre-generated 'src/lxml/lxml.etree.c' needs to be available.
Using build configuration of libxslt 1.1.12
Building against libxml2/libxslt in the following directory: /usr/lib
unable to execute gcc-4.0: No such file or directory
error: Setup script exited with …我在mac的2.5.2版本旁边安装了python 2.6.我一做到这一点,python2.6 manage.py runserver就失败了,因为找不到django.core.management.
从shell中,import django返回importerror:没有名为django的模块.
为什么？
下面的代码生成此错误.我无法弄清楚为什么.如果ElementTree有解析,为什么它没有tostring？http://docs.python.org/library/xml.etree.elementtree.html#xml.etree.ElementTree.ElementTree
from xml.etree.ElementTree import ElementTree
...
tree = ElementTree()
node = ElementTree()
node = tree.parse(open("my_xml.xml"))
text = node.tostring()