第1.2.1章树莓派python编程环境

系统管理员 2022-03-16 09:38 301阅读 0赞

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  
![1][]![2][]  
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][Python2.7 _ 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`OpenSSL.SSL.WantReadError`，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][pip_sslerror]  
执行命令`pip install pandas -i http://pypi.douban.com/simple --trusted-host pypi.douban.com`  
安装成功,pandas就是想安装的软件.  
[更换pycharm源][pycharm]，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][PyPI],树莓派的配置文件在`/etc/pip.conf`

nano /etc/pip.conf 
    # 添加如下内容
    [global]
    #extra-index-url=https://www.piwheels.org/simple
    index-url = http://pypi.douban.com/simple
    [install]
    trusted-host=pypi.douban.com

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.py3-none-any.whl/urllib3/contrib/pyopenssl.py", line 417, in wrap_socket
        cnx.do_handshake()
      File "/usr/lib/python3/dist-packages/OpenSSL/SSL.py", line 1426, in do_handshake
        self._raise_ssl_error(self._ssl, result)
      File "/usr/lib/python3/dist-packages/OpenSSL/SSL.py", line 1149, in _raise_ssl_error
        raise WantReadError()
    OpenSSL.SSL.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.py3-none-any.whl/urllib3/connectionpool.py", line 350, in _make_request
        self._validate_conn(conn)
      File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 837, in _validate_conn
        conn.connect()
      File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connection.py", line 323, in connect
        ssl_context=context)
      File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/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.py3-none-any.whl/urllib3/contrib/pyopenssl.py", line 421, in wrap_socket
        raise timeout('select timed out')
    socket.timeout: 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.py3-none-any.whl/urllib3/connectionpool.py", line 594, in urlopen
        chunked=chunked)
      File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 353, in _make_request
        self._raise_timeout(err=e, url=url, timeout_value=conn.timeout)
      File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 313, in _raise_timeout
        raise ReadTimeoutError(self, url, "Read timed out. (read timeout=%s)" % timeout_value)
    requests.packages.urllib3.exceptions.ReadTimeoutError: HTTPSConnectionPool(host='www.piwheels.org', 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/basecommand.py", line 215, in main
        status = self.run(options, args)
      File "/usr/lib/python3/dist-packages/pip/commands/install.py", line 353, in run
        wb.build(autobuilding=True)
      File "/usr/lib/python3/dist-packages/pip/wheel.py", line 749, in build
        self.requirement_set.prepare_files(self.finder)
      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
        self.link = finder.find_requirement(self, upgrade)
      File "/usr/lib/python3/dist-packages/pip/index.py", line 465, in find_requirement
        all_candidates = self.find_all_candidates(req.name)
      File "/usr/lib/python3/dist-packages/pip/index.py", line 423, in find_all_candidates
        for page in self._get_pages(url_locations, project_name):
      File "/usr/lib/python3/dist-packages/pip/index.py", line 568, in _get_pages
        page = self._get_page(location)
      File "/usr/lib/python3/dist-packages/pip/index.py", line 683, in _get_page
        return HTMLPage.get_page(link, session=self.session)
      File "/usr/lib/python3/dist-packages/pip/index.py", line 792, in get_page
        "Cache-Control": "max-age=600",
      File "/usr/share/python-wheels/requests-2.12.4-py2.py3-none-any.whl/requests/sessions.py", line 501, in get
        return self.request('GET', url, **kwargs)
      File "/usr/lib/python3/dist-packages/pip/download.py", line 386, in request
        return super(PipSession, self).request(method, url, *args, **kwargs)
      File "/usr/share/python-wheels/requests-2.12.4-py2.py3-none-any.whl/requests/sessions.py", line 488, in request
        resp = self.send(prep, **send_kwargs)
      File "/usr/share/python-wheels/requests-2.12.4-py2.py3-none-any.whl/requests/sessions.py", line 609, in send
        r = adapter.send(request, **kwargs)
      File "/usr/share/python-wheels/CacheControl-0.11.7-py2.py3-none-any.whl/cachecontrol/adapter.py", line 47, in send
        resp = super(CacheControlAdapter, self).send(request, **kw)
      File "/usr/share/python-wheels/requests-2.12.4-py2.py3-none-any.whl/requests/adapters.py", line 423, in send
        timeout=timeout
      File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 643, in urlopen
        _stacktrace=sys.exc_info()[2])
      File "/usr/share/python-wheels/urllib3-1.19.1-py2.py3-none-any.whl/urllib3/util/retry.py", 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（libxslt.so.1: cannot open shared object file）][lxml_libxslt.so.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][3B_]  
、[更换树莓派软件源（stretch 版本的）][stretch] 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/sources.list
    # 添加下面的源
    deb https://mirrors.ustc.edu.cn/raspbian/raspbian/ stretch main contrib non-free rpi
    
    sudo nano /etc/apt/sources.list.d/raspi.list
    # 添加下面的源
    deb https://mirrors.ustc.edu.cn/archive.raspberrypi.org/ stretch main ui
    
    sudo apt-get update -y 
    sudo apt-get dist-upgrade -y

![1][1 1]

root@raspberrypi:~# sudo apt update && sudo apt -y upgrade
    获取:1 http://mirrors.ustc.edu.cn/raspbian/raspbian stretch InRelease [2,281 B]
    错误:1 http://mirrors.ustc.edu.cn/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 http://mirrors.ustc.edu.cn/archive.raspberrypi.org stretch InRelease [2,281 B]   
    错误:2 http://mirrors.ustc.edu.cn/archive.raspberrypi.org 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 http://mirrors.ustc.edu.cn/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 http://mirrors.ustc.edu.cn/archive.raspberrypi.org/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 http://raspbian.raspberrypi.org/raspbian stretch/main armhf python3-bs4 all 4.5.3-1 [86.6 kB]
    获取:2 http://raspbian.raspberrypi.org/raspbian stretch/main armhf python3-webencodings all 0.5-2 [10.4 kB]
    错误:1 http://raspbian.raspberrypi.org/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 installed**  
`pip 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, zope.interface
      Running setup.py bdist_wheel for lxml ... error
      Complete output from command /usr/bin/python3 -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-on0bo_yv/lxml/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();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 1**  
`pip install lxml`的时候，提示下面的异常，解决方案是参考[’arm-linux-gnueabihf-gcc’ failed][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][_pip_lxml]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/etree.c -o build/temp.linux-armv7l-3.5/src/lxml/etree.o -w
        In file included from src/lxml/etree.c:687:0:
        src/lxml/includes/etree_defs.h:14:31: fatal error: libxml/xmlversion.h: 没有那个文件或目录
         #include "libxml/xmlversion.h"
                                       ^
        compilation terminated.
        Compile failed: command 'arm-linux-gnueabihf-gcc' failed with exit status 1
        cc -I/usr/include/libxml2 -c /tmp/xmlXPathInitt9k2qdli.c -o tmp/xmlXPathInitt9k2qdli.o
        /tmp/xmlXPathInitt9k2qdli.c:1:26: fatal error: libxml/xpath.h: 没有那个文件或目录
         #include "libxml/xpath.h"
                                  ^
        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 https://mirrors.ustc.edu.cn/raspbian/raspbian stretch/main armhf libevent-core-2.0-5 armhf 2.0.21-stable-3
      Could not resolve host: mirrors.ustc.edu.cn
    错误:2 https://mirrors.ustc.edu.cn/raspbian/raspbian stretch/main armhf libevent-extra-2.0-5 armhf 2.0.21-stable-3
      Could not resolve host: mirrors.ustc.edu.cn
    获取:3 https://mirrors.ustc.edu.cn/raspbian/raspbian stretch/main armhf libevent-pthreads-2.0-5 armhf 2.0.21-stable-3 [43.6 kB]
    获取:4 https://mirrors.ustc.edu.cn/raspbian/raspbian stretch/main armhf libevent-openssl-2.0-5 armhf 2.0.21-stable-3 [48.1 kB]
    获取:5 https://mirrors.ustc.edu.cn/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 https://mirrors.ustc.edu.cn/raspbian/raspbian/pool/main/libe/libevent/libevent-core-2.0-5_2.0.21-stable-3_armhf.deb  Could not resolve host: mirrors.ustc.edu.cn
    E: 无法下载 https://mirrors.ustc.edu.cn/raspbian/raspbian/pool/main/libe/libevent/libevent-extra-2.0-5_2.0.21-stable-3_armhf.deb  Could not resolve host: mirrors.ustc.edu.cn
    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？

[1]: https://img-blog.csdnimg.cn/20190227131046395.png
[2]: /images/20220316/1ac657e3399f48be9b0fee1970c8c6d1.png
[Python2.7 _ Python3]: https://www.jianshu.com/p/61b3119ab3f5?utm_campaign=maleskine&utm_content=note&utm_medium=reader_share&utm_source=qzone
[pip_sslerror]: https://blog.csdn.net/chr1341901410/article/details/80995451
[pycharm]: https://www.douban.com/note/617571931/
[PyPI]: https://www.cnblogs.com/sunnydou/p/5801760.html
[lxml_libxslt.so.1_ cannot open shared object file]: https://blog.csdn.net/dfly_zx/article/details/80769845
[3B_]: https://blog.csdn.net/kxwinxp/article/details/78370980
[stretch]: https://blog.csdn.net/qq_38632611/article/details/79710689?utm_source=blogxgwz1
[1 1]: /images/20220316/84cff2f2f314463d8faba800f8156e7f.png
[arm-linux-gnueabihf-gcc_ failed]: https://blog.csdn.net/talkxin/article/details/52181650
[_pip_lxml]: https://blog.csdn.net/lincifer/article/details/51296559