1 一个爬图片pic的代码的例子

下面这段是爬一些图片pic的代码
学写了一段bs的代码，但是马上报错

#E:\work\FangCloudV2\personal_space\2learn\python3\py0001.txt


import requests
from bs4 import BeautifulSoup

url="https://movie.douban.com/celebrity/1011562/photos/"
res=requests.get(url)
content= BeautifulSoup(res.text, "html.parser")
data=content.find_all("div",attrs={'class':'cover'})
picture_list=[]

for d in data:
    plist=d.find("img")["src"]
    picture_list.append(plist)
print (picture_list)

null刘涛最新图片https://movie.douban.com/celebrity/1011562/photos/

2 直接在cmd里 python运行报错

2.1 运行报错

运行cmd
python 文件报错
报错内容： ModuleNotFoundError: No module named 'bs4'

2.2 报错原因

这个报错的原因，是因为在默认的python目录下并没有安装 bs4 （BeautifulSoup）这个模块，当然会报错
那如果是以下情况，就不会遇到这个报错

如果是，先在默认python下安装了 bs4 ，就不会遇到这种报错
如果是我直接使用 anaconda环境下的 cmd 或者 spygt ,pythoncharm

2.3 查询pc里 python相关的所有安装内容

接下来的问题就是
（因为使用的电脑环境并不一定是自己安装的环境，也可能很久后忘记了）
我是否可以在安装前知道，已经安装了 bs4?
同样，我想知道是否已经安装过 pip ,requeset 等其他模块
这些模块装在哪儿呢？

2.3.1 查看所有python版本的命令

py -0p
可以查看电脑中所有的 python版本
其中* 号是默认的版本
我这里显示1个是默认的，一个 anaconda里的

2.3.2 pip list 列表显示

pip list
pip list --format=columns
可以查看pip下的各种模块
而这个pip list 显示的各个模块，实际对应硬盘上的哪个路径呢？
Python311\site-packages
\Python37_64\Lib\site-packages\pip\_vendor
C:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\Lib\site-packages\pip\_vendor

\Python37_64\Lib\site-packages\pip\_vendor

2.3.3 pip show 模块命令

pip show pip
pip show requests
显示详细信息： name , version ，安装位置等
如果是没有安装的模块，就会找不到
比如这里的 bs4

2.3.4 pip 的其他常用命令

pip --help # 可以查看帮助，全部命令
pip --version
pip list
pip list -0
pip show XXX模块
pip install
pip install --upgrade XXX
pip uninstall
pip search XXX

Commands:

install Install packages.
download Download packages.
uninstall Uninstall packages.
freeze Output installed packages in requirements format.
inspect Inspect the python environment.
list List installed packages.
show Show information about installed packages.
check Verify installed packages have compatible dependencies.
config Manage local and global configuration.
search Search PyPI for packages.
cache Inspect and manage pip's wheel cache.
index Inspect information available from package indexes.
wheel Build wheels from your requirements.
hash Compute hashes of package archives.
completion A helper command used for command completion.
debug Show information useful for debugging.
help Show help for commands.

General Options:

-h, --help Show help.
--debug Let unhandled exceptions propagate outside the main subroutine, instead of logging them
to stderr.
--isolated Run pip in an isolated mode, ignoring environment variables and user configuration.
--require-virtualenv Allow pip to only run in a virtual environment; exit with an error otherwise.
--python <python> Run pip with the specified Python interpreter.
-v, --verbose Give more output. Option is additive, and can be used up to 3 times.
-V, --version Show version and exit.
-q, --quiet Give less output. Option is additive, and can be used up to 3 times (corresponding to
WARNING, ERROR, and CRITICAL logging levels).
--log <path> Path to a verbose appending log.
--no-input Disable prompting for input.
--keyring-provider <keyring_provider>
Enable the credential lookup via the keyring library if user input is allowed. Specify
which mechanism to use [disabled, import, subprocess]. (default: disabled)
--proxy <proxy> Specify a proxy in the form scheme://[user:passwd@]proxy.server:port.
--retries <retries> Maximum number of retries each connection should attempt (default 5 times).
--timeout <sec> Set the socket timeout (default 15 seconds).
--exists-action <action> Default action when a path already exists: (s)witch, (i)gnore, (w)ipe, (b)ackup,
(a)bort.
--trusted-host <hostname> Mark this host or host:port pair as trusted, even though it does not have valid or any
HTTPS.
--cert <path> Path to PEM-encoded CA certificate bundle. If provided, overrides the default. See 'SSL
Certificate Verification' in pip documentation for more information.
--client-cert <path> Path to SSL client certificate, a single file containing the private key and the
certificate in PEM format.
--cache-dir <dir> Store the cache data in <dir>.
--no-cache-dir Disable the cache.
--disable-pip-version-check
Don't periodically check PyPI to determine whether a new version of pip is available for
download. Implied with --no-index.
--no-color Suppress colored output.
--no-python-version-warning
Silence deprecation warnings for upcoming unsupported Pythons.
--use-feature <feature> Enable new functionality, that may be backward incompatible.
--use-deprecated <feature> Enable deprecated functionality, that will be removed in the future.

2.3.5 不太好用的命令

python -m site
显示的是 py3.7这一层目录的文件夹目录位置！！
C:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64
而不是pip 下安装模块的文件夹目录位置！！
C:\Program Files (x86)\Microsoft Visual Studio\Shared\Python37_64\Lib\site-packages\pip\_vendor