Learn Python with Steem #08 笔记
[toc]
划重点
模块、包
模块是一个XXX.py文件，Python中以模块的方式组织代码片段（函数，类，变量）。
包是一个目录，里面有一些模块或者子目录，Python中以包的方式管理模块。
- 使用模块
要使用模块，需要先导入模块，使用关键字import来导入模块。
这是我们使用Python标准库和第三方库的方式。
- 安装模块
第三方模块需要自己安装，可以通过Python的包管理工具pip安装、还可以下载模块源码来安装。
编程练习
from steem import Steem
s = Steem()
balance = s.get_account('yjcps')['sbd_balance']
print(balance)
4.484 SBD
%%file check_balance.py
from steem import Steem
import sys
account_name = sys.argv[1]
s = Steem()
balance = s.get_account(account_name)['sbd_balance']
print(balance)
Overwriting check_balance.py
!python check_balance.py yjcps
4.484 SBD
!python check_balance.py dapeng
129.840 SBD
补充
pip的安装与使用
- 安装pip
先下载get-pip.py文件
也可以在浏览器访问网址 https://bootstrap.pypa.io/get-pip.py ，直接下载保存文件。
然后终端用Python执行这个文件
python get-pip.py
- 升级pip
!pip install -U pip
Requirement already up-to-date: pip in i:\python~1\lib\site-packages (18.0)
!python -m pip install -U pip
Requirement already up-to-date: pip in i:\python~1\lib\site-packages (18.0)
- 用pip安装Python包
!pip install requests
Collecting requests
Downloading https://files.pythonhosted.org/packages/65/47/7e02164a2a3db50ed6d8a6ab1d6d60b69c4c3fdf57a284257925dfc12bda/requests-2.19.1-py2.py3-none-any.whl (91kB)
Requirement already satisfied: chardet<3.1.0,>=3.0.2 in i:\python~1\lib\site-packages (from requests) (3.0.4)
Requirement already satisfied: urllib3<1.24,>=1.21.1 in i:\python~1\lib\site-packages (from requests) (1.22)
Requirement already satisfied: idna<2.8,>=2.5 in i:\python~1\lib\site-packages (from requests) (2.6)
Requirement already satisfied: certifi>=2017.4.17 in i:\python~1\lib\site-packages (from requests) (2018.4.16)
Installing collected packages: requests
Successfully installed requests-2.19.1
wxpy 0.3.9.8 has requirement itchat==1.2.32, but you'll have itchat 1.3.10 which is incompatible.
pyspider 0.3.10 has requirement tornado<=4.5.3,>=3.2, but you'll have tornado 5.0.2 which is incompatible.
# 指定包的版本
!pip install requests==2.17.1
Collecting requests==2.17.1
Downloading https://files.pythonhosted.org/packages/50/41/f6fdaf24a80c726a72f76b15869a20734b7a527081129a380ddce99ffae0/requests-2.17.1-py2.py3-none-any.whl (87kB)
Requirement already satisfied: chardet<3.1.0,>=3.0.2 in i:\python~1\lib\site-packages (from requests==2.17.1) (3.0.4)
Requirement already satisfied: urllib3<1.22,>=1.21.1 in i:\python~1\lib\site-packages (from requests==2.17.1) (1.21.1)
Requirement already satisfied: certifi>=2017.4.17 in i:\python~1\lib\site-packages (from requests==2.17.1) (2018.4.16)
Requirement already satisfied: idna<2.6,>=2.5 in i:\python~1\lib\site-packages (from requests==2.17.1) (2.5)
Installing collected packages: requests
Successfully installed requests-2.17.1
wxpy 0.3.9.8 has requirement itchat==1.2.32, but you'll have itchat 1.3.10 which is incompatible.
pyspider 0.3.10 has requirement tornado<=4.5.3,>=3.2, but you'll have tornado 5.0.2 which is incompatible.
- 安装Wheels格式的包
可以在 https://pypi.org/ 网站搜索Python包，下载与你环境对应的wheel文件
# 安装命令
!pip install K:\scrypt-0.8.5-cp36-cp36m-win32.whl
Requirement already satisfied: scrypt==0.8.5 from file:///K:/scrypt-0.8.5-cp36-cp36m-win32.whl in i:\python~1\lib\site-packages (0.8.5)
Requirement 'K:\\scrypt-0.8.5-cp36-cp36m-win32.whl' looks like a filename, but the file does not exist
- 指定安装的镜像源
一般来说，使用国内的镜像源按Python包速度更快、更顺畅。
- V2EX：http://pypi.v2ex.com/simple
- 豆瓣：http://pypi.douban.com/simple
- 中国科学技术大学：http://pypi.mirrors.ustc.edu.cn/simple/
- 清华：https://pypi.tuna.tsinghua.edu.cn/simple
!pip install -i https://pypi.douban.com/simple/ requests
Looking in indexes: https://pypi.douban.com/simple/
Collecting requests
Downloading https://pypi.doubanio.com/packages/65/47/7e02164a2a3db50ed6d8a6ab1d6d60b69c4c3fdf57a284257925dfc12bda/requests-2.19.1-py2.py3-none-any.whl (91kB)
Requirement already satisfied: urllib3<1.24,>=1.21.1 in i:\python~1\lib\site-packages (from requests) (1.21.1)
Requirement already satisfied: certifi>=2017.4.17 in i:\python~1\lib\site-packages (from requests) (2018.4.16)
Requirement already satisfied: idna<2.8,>=2.5 in i:\python~1\lib\site-packages (from requests) (2.5)
Requirement already satisfied: chardet<3.1.0,>=3.0.2 in i:\python~1\lib\site-packages (from requests) (3.0.4)
Installing collected packages: requests
Successfully installed requests-2.19.1
wxpy 0.3.9.8 has requirement itchat==1.2.32, but you'll have itchat 1.3.10 which is incompatible.
pyspider 0.3.10 has requirement tornado<=4.5.3,>=3.2, but you'll have tornado 5.0.2 which is incompatible.
# 升级
!pip install --upgrade requests
Collecting requests
Using cached https://files.pythonhosted.org/packages/65/47/7e02164a2a3db50ed6d8a6ab1d6d60b69c4c3fdf57a284257925dfc12bda/requests-2.19.1-py2.py3-none-any.whl
Requirement already satisfied, skipping upgrade: chardet<3.1.0,>=3.0.2 in i:\python~1\lib\site-packages (from requests) (3.0.4)
Requirement already satisfied, skipping upgrade: certifi>=2017.4.17 in i:\python~1\lib\site-packages (from requests) (2018.4.16)
Requirement already satisfied, skipping upgrade: idna<2.8,>=2.5 in i:\python~1\lib\site-packages (from requests) (2.5)
Requirement already satisfied, skipping upgrade: urllib3<1.24,>=1.21.1 in i:\python~1\lib\site-packages (from requests) (1.21.1)
Installing collected packages: requests
Found existing installation: requests 2.17.1
Uninstalling requests-2.17.1:
Successfully uninstalled requests-2.17.1
Successfully installed requests-2.19.1
wxpy 0.3.9.8 has requirement itchat==1.2.32, but you'll have itchat 1.3.10 which is incompatible.
pyspider 0.3.10 has requirement tornado<=4.5.3,>=3.2, but you'll have tornado 5.0.2 which is incompatible.
- 用pip卸载Python包
!pip uninstall requests -y
Uninstalling requests-2.19.1:
Successfully uninstalled requests-2.19.1
- 查看哪些包可升级
!pip list --outdated
Package Version Latest Type
--------------------- --------- --------- -----
aiohttp 3.2.1 3.3.2 wheel
astroid 1.6.4 2.0.4 wheel
Automat 0.6.0 0.7.0 wheel
beautifulsoup4 4.6.0 4.6.3 wheel
bitarray 0.8.1 0.8.3 sdist
certifi 2018.4.16 2018.8.13 wheel
...
twisted 17.9.0 18.7.0 sdist
urllib3 1.21.1 1.23 wheel
WeRoBot 1.4.1 1.6.0 wheel
widgetsnbextension 3.2.1 3.4.0 wheel
WsgiDAV 2.3.0 2.4.1 wheel
wxPython 4.0.1 4.0.3 wheel
yarl 1.2.4 1.2.6 wheel
- 查看包的安装信息
!pip show --files requests
Name: requests
Version: 2.19.1
Summary: Python HTTP for Humans.
Home-page: http://python-requests.org
Author: Kenneth Reitz
Author-email: me@kennethreitz.org
License: Apache 2.0
Location: i:\python~1\lib\site-packages
Requires: idna, urllib3, chardet, certifi
Required-by: yarg, wxpy, WeRoBot, requests-download, pyspider, pynsist, itchat, httpie
Files:
requests-2.19.1.dist-info\DESCRIPTION.rst
requests-2.19.1.dist-info\INSTALLER
requests-2.19.1.dist-info\LICENSE.txt
...
requests\status_codes.py
requests\structures.py
requests\utils.py
- 导出包的安装信息到指定文件
!pip freeze > requirements.txt
%pycat requirements.txt
aiohttp==3.2.1
appdirs==1.4.3
asn1crypto==0.24.0
astroid==1.6.4
async-timeout==3.0.0
...
windrose==1.6.3
wrapt==1.10.11
WsgiDAV==2.3.0
wxpy==0.3.9.8
wxPython==4.0.1
xmltodict==0.11.0
yapf==0.22.0
yarg==0.1.9
yarl==1.2.4
zope.interface==4.5.0
- 从指定文件安装指定的包
!pip install -r requirements.txt
Requirement already satisfied: aiohttp==3.2.1 in i:\python~1\lib\site-packages (from -r requirements.txt (line 1)) (3.2.1)
Requirement already satisfied: appdirs==1.4.3 in i:\python~1\lib\site-packages (from -r requirements.txt (line 2)) (1.4.3)
Requirement already satisfied: asn1crypto==0.24.0 in i:\python~1\lib\site-packages (from -r requirements.txt (line 3)) (0.24.0)
Requirement already satisfied: astroid==1.6.4 in d:\users\tracis\appdata\roaming\python\python36\site-packages (from -r requirements.txt (line 4)) (1.6.4)
Requirement already satisfied: async-timeout==3.0.0 in i:\python~1\lib\site-packages (from -r requirements.txt (line 5)) (3.0.0)
...
Requirement already satisfied: pip>=9.0.1 in i:\python~1\lib\site-packages (from pipenv==2018.7.1->-r requirements.txt (line 91)) (18.0)
[DA series - Learn Python with Steem]
[DA series - Learn Python with Steem #01] 安裝Python、文字編輯器與哈囉！
[DA series - Learn Python with Steem #08] 函式庫(Modules)的安裝與使用，準備好玩Steem！