树莓派3B+，默认的python版本是2.7.13，但是操作系统自带了python3.5.3的IDE
因为现在主流都是用python3，那么我怎么讲python的环境切换到3呢？
1 python环境切换
参考将树莓派内置的 Python2.7 升级成 Python3
# 卸载 python2.7
sudo apt remove python
# 自动清理 python2.7 的依赖
sudo apt autoremove
因为树莓派3B+自带python3，所以只需要执行，即可。
sudo ln -s /usr/bin/python3.5 /usr/bin/python
sudo ln -s /usr/bin/pip3 /usr/bin/pip
如果没有python3，则执行sudo apt install python3进行安装
2 安装其他插件
直接安装文件可能会出错，比如pip install pandas，就会提示，这个时候参考章节3.1更换pypi国内源就可以了。
3 异常
3.1 更换pypi国内源
下面这个异常OpenSSL的错误，解决方案参考解决pip安装出现sslerror的问题
执行命令pip install pandas -i /simple --trusted-host
安装成功,pandas就是想安装的软件.
更换pycharm源，这上面说豆瓣的源是最好用的。
那么也就是说，我需要先更改源，再安装就不用后面带那么一长串了。
配置豆瓣源,参考PyPI使用国内源,树莓派的配置文件在/etc/
nano /etc/
# 添加如下内容
[global]
#extra-index-url=/simple
index-url = /simple
[install]
trusted-host=
root@raspberrypi:/usr/bin# pip install pandas
Collecting pandas
Exception:
Traceback (most recent call last):
File "/usr/share/python-wheels/urllib3-1.19.1-py2./urllib3/contrib/", line 417, in wrap_socket
cnx.do_handshake()
File "/usr/lib/python3/dist-packages/OpenSSL/", line 1426, in do_handshake
self._raise_ssl_error(self._ssl, result)
File "/usr/lib/python3/dist-packages/OpenSSL/", line 1149, in _raise_ssl_error
raise WantReadError()
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/share/python-wheels/urllib3-1.19.1-py2./urllib3/", line 350, in _make_request
self._validate_conn(conn)
File "/usr/share/python-wheels/urllib3-1.19.1-py2./urllib3/", line 837, in _validate_conn
()
File "/usr/share/python-wheels/urllib3-1.19.1-py2./urllib3/", line 323, in connect
ssl_context=context)
File "/usr/share/python-wheels/urllib3-1.19.1-py2./urllib3/util/ssl_.py", line 324, in ssl_wrap_socket
return context.wrap_socket(sock, server_hostname=server_hostname)
File "/usr/share/python-wheels/urllib3-1.19.1-py2./urllib3/contrib/", line 421, in wrap_socket
raise timeout('select timed out')
: select timed out
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/share/python-wheels/urllib3-1.19.1-py2./urllib3/", line 594, in urlopen
chunked=chunked)
File "/usr/share/python-wheels/urllib3-1.19.1-py2./urllib3/", line 353, in _make_request
self._raise_timeout(err=e, url=url, timeout_value=)
File "/usr/share/python-wheels/urllib3-1.19.1-py2./urllib3/", line 313, in _raise_timeout
raise ReadTimeoutError(self, url, "Read timed out. (read timeout=%s)" % timeout_value)
.: HTTPSConnectionPool(host='', port=443): Read timed out. (read timeout=15)
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/pip/", line 215, in main
status = (options, args)
File "/usr/lib/python3/dist-packages/pip/commands/", line 353, in run
(autobuilding=True)
File "/usr/lib/python3/dist-packages/pip/", line 749, in build
self.requirement_set.prepare_files()
File "/usr/lib/python3/dist-packages/pip/req/req_set.py", line 380, in prepare_files
ignore_dependencies=self.ignore_dependencies))
File "/usr/lib/python3/dist-packages/pip/req/req_set.py", line 554, in _prepare_file
require_hashes
File "/usr/lib/python3/dist-packages/pip/req/req_install.py", line 278, in populate_link
= finder.find_requirement(self, upgrade)
File "/usr/lib/python3/dist-packages/pip/", line 465, in find_requirement
all_candidates = self.find_all_candidates()
File "/usr/lib/python3/dist-packages/pip/", line 423, in find_all_candidates
for page in self._get_pages(url_locations, project_name):
File "/usr/lib/python3/dist-packages/pip/", line 568, in _get_pages
page = self._get_page(location)
File "/usr/lib/python3/dist-packages/pip/", line 683, in _get_page
return HTMLPage.get_page(link, session=)
File "/usr/lib/python3/dist-packages/pip/", line 792, in get_page
"Cache-Control": "max-age=600",
File "/usr/share/python-wheels/requests-2.12.4-py2./requests/", line 501, in get
return ('GET', url, **kwargs)
File "/usr/lib/python3/dist-packages/pip/", line 386, in request
return super(PipSession, self).request(method, url, *args, **kwargs)
File "/usr/share/python-wheels/requests-2.12.4-py2./requests/", line 488, in request
resp = (prep, **send_kwargs)
File "/usr/share/python-wheels/requests-2.12.4-py2./requests/", line 609, in send
r = (request, **kwargs)
File "/usr/share/python-wheels/CacheControl-0.11.7-py2./cachecontrol/", line 47, in send
resp = super(CacheControlAdapter, self).send(request, **kw)
File "/usr/share/python-wheels/requests-2.12.4-py2./requests/", line 423, in send
timeout=timeout
File "/usr/share/python-wheels/urllib3-1.19.1-py2./urllib3/", line 643, in urlopen
_stacktrace=sys.exc_info()[2])
File "/usr/share/python-wheels/urllib3-1.19.1-py2./urllib3/util/", line 315, in increment
total -= 1
TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'
3.2 更新树莓派的源
树莓派安装lxml包后报错（.1: cannot open shared object file）,但是执行sudo apt-get install python3-lxml提示错误,莫不是要我把树莓派的源给更改了，于是尝试
参考树莓派3B+ 软件源更改
、更换树莓派软件源（stretch 版本的） 但是提示下面的异常，查看配置并没有错误，而且互联网上面的资料都是这个中国科技大学的源，那么问题出在哪里呢？既然提示网络需要认证，那么我尝试将源改成https的，结果果然成功
sudo nano /etc/apt/
# 添加下面的源
deb /raspbian/raspbian/ stretch main contrib non-free rpi
sudo nano /etc/apt//
# 添加下面的源
deb // stretch main ui
sudo apt-get update -y
sudo apt-get dist-upgrade -y
root@raspberrypi:~# sudo apt update && sudo apt -y upgrade
获取:1 /raspbian/raspbian stretch InRelease [2,281 B]
错误:1 /raspbian/raspbian stretch InRelease
明文签署文件不可用，结果为‘NOSPLIT’（您的网络需要认证吗？）
获取:2 / stretch InRelease [2,281 B]
错误:2 / stretch InRelease
明文签署文件不可用，结果为‘NOSPLIT’（您的网络需要认证吗？）
已下载 4,562 B，耗时 5秒 (836 B/s)
正在读取软件包列表... 完成
E: 无法下载 /raspbian/raspbian/dists/stretch/InRelease 明文签署文件不可用，结果为‘NOSPLIT’（您的网络需要认证吗？）
E: 无法下载 //dists/stretch/InRelease 明文签署文件不可用，结果为‘NOSPLIT’（您的网络需要认证吗？）
E: 部分索引文件下载失败。如果忽略它们，那将转而使用旧的索引文件
root@raspberrypi:~# sudo apt-get install python3-lxml
正在读取软件包列表... 完成
正在分析软件包的依赖关系树
正在读取状态信息... 完成
将会同时安装下列软件：
python3-bs4 python3-html5lib python3-webencodings
建议安装：
python3-genshi python3-lxml-dbg python-lxml-doc
下列【新】软件包将被安装：
python3-bs4 python3-html5lib python3-lxml python3-webencodings
升级了 0 个软件包，新安装了 4 个软件包，要卸载 0 个软件包，有 0 个软件包未被升级。
需要下载 975 kB 的归档。
解压缩后会消耗 4,077 kB 的额外空间。
您希望继续执行吗？ [Y/n] y
获取:1 /raspbian stretch/main armhf python3-bs4 all 4.5.3-1 [86.6 kB]
获取:2 /raspbian stretch/main armhf python3-webencodings all 0.5-2 [10.4 kB]
错误:1 /raspbian stretch/main armhf python3-bs4 all 4.5.3-1
Hash 校验和不符
Hashes of expected file:
- SHA256:01cc4be4b93254c986f9f08dc331b212dd2d69ac9399115490d82056c510666c
- SHA1:d9a1b3bedbc58fc40c9b54f86b025a3117d16f8a [weak]
- MD5Sum:88cc1efca381156284b161f74652669b [weak]
- Filesize:86584 [weak]
Hashes of received file:
- SHA256:138422fcd39b082e6defe9212cd3e4f9bf0ab2414cd8067082e472e859c77d69
- SHA1:862fe9be5c55082c173de5888fa1aca481e18bbf [weak]
- MD5Sum:25bd48a6da28d0583c181a4abcba6a4a [weak]
- Filesize:2281 [weak]
Last modification reported: Wed, 12 Oct 2016 01:25:02 +0000
3.3 make sure the development packages of libxml2 and libxslt are installedpip install lxml的时候，提示下面的异常，这个问题需要配置树莓派的源，参见章节3.2
Building wheels for collected packages: lxml, Twisted, PyDispatcher,
Running bdist_wheel for lxml ... error
Complete output from command /usr/bin/python3 -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-on0bo_yv/lxml/';f=getattr(tokenize, 'open', open)(__file__);code=().replace('\r\n', '\n');();exec(compile(code, __file__, 'exec'))" bdist_wheel -d /tmp/tmpgp7_bktvpip-wheel- --python-tag cp35:
Building lxml version 4.3.1.
Building without Cython.
ERROR: b'/bin/sh: 1: xslt-config: not found\n'
** make sure the development packages of libxml2 and libxslt are installed **
3.4 error: command ‘arm-linux-gnueabihf-gcc’ failed with exit status 1pip install lxml的时候，提示下面的异常，解决方案是参考’arm-linux-gnueabihf-gcc’ failed就高兴早了，最终参考 解决使用pip安装lxml包报错问题才得以解决
sudo apt-get install python3-dev libxml2-dev libxslt1-dev zlib1g-dev
mat-security -Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -DCYTHON_CLINE_IN_TRACEBACK=0 -Isrc -Isrc/lxml/includes -I/usr/include/python3.5m -c src/lxml/ -o build/-armv7l-3.5/src/lxml/ -w
In file included from src/lxml/:687:0:
src/lxml/includes/etree_defs.h:14:31: fatal error: libxml/: 没有那个文件或目录
#include "libxml/"
^
compilation terminated.
Compile failed: command 'arm-linux-gnueabihf-gcc' failed with exit status 1
cc -I/usr/include/libxml2 -c /tmp/ -o tmp/
/tmp/:1:26: fatal error: libxml/: 没有那个文件或目录
#include "libxml/"
^
compilation terminated.
*********************************************************************************
Could not find function xmlCheckVersion in library libxml2. Is libxml2 installed?
*********************************************************************************
error: command 'arm-linux-gnueabihf-gcc' failed with exit status 1
3.5 sudo apt-get install libevent-dev 安装失败
出现这个原因，是因为没有执行sudo apt-get dist-upgrade -y
root@raspberrypi:~# sudo apt-get install libevent-dev
正在读取软件包列表... 完成
正在分析软件包的依赖关系树
正在读取状态信息... 完成
将会同时安装下列软件：
libevent-core-2.0-5 libevent-extra-2.0-5 libevent-openssl-2.0-5 libevent-pthreads-2.0-5
下列【新】软件包将被安装：
libevent-core-2.0-5 libevent-dev libevent-extra-2.0-5 libevent-openssl-2.0-5 libevent-pthreads-2.0-5
升级了 0 个软件包，新安装了 5 个软件包，要卸载 0 个软件包，有 88 个软件包未被升级。
需要下载 492 kB 的归档。
解压缩后会消耗 1,622 kB 的额外空间。
您希望继续执行吗？ [Y/n] y
错误:1 /raspbian/raspbian stretch/main armhf libevent-core-2.0-5 armhf 2.0.21-stable-3
Could not resolve host:
错误:2 /raspbian/raspbian stretch/main armhf libevent-extra-2.0-5 armhf 2.0.21-stable-3
Could not resolve host:
获取:3 /raspbian/raspbian stretch/main armhf libevent-pthreads-2.0-5 armhf 2.0.21-stable-3 [43.6 kB]
获取:4 /raspbian/raspbian stretch/main armhf libevent-openssl-2.0-5 armhf 2.0.21-stable-3 [48.1 kB]
获取:5 /raspbian/raspbian stretch/main armhf libevent-dev armhf 2.0.21-stable-3 [221 kB]
已下载 313 kB，耗时 46秒 (6,689 B/s)
E: 无法下载 /raspbian/raspbian/pool/main/libe/libevent/libevent-core-2.0-5_2.0.21-stable-3_armhf.deb Could not resolve host:
E: 无法下载 /raspbian/raspbian/pool/main/libe/libevent/libevent-extra-2.0-5_2.0.21-stable-3_armhf.deb Could not resolve host:
E: 有几个软件包无法下载，要不运行 apt-get update 或者加上 --fix-missing 的选项再试试？