conda管理Python库和虚拟环境

conda 是一个开源的跨平台软件包管理系统和环境管理系统，用于安装、运行和协调不同版本的软件包和其依赖项。它最初是为 Python 语言而设计的，但现在已经支持多种编程语言和工具。conda 可以轻松地创建和使用虚拟环境，这些环境可以独立于系统上的其他环境和安装的软件包运行。conda 还有一个广泛的软件包仓库，其中包含许多科学计算、数据分析和机器学习软件包，可供用户直接安装和使用。

conda 支持 Python、R、Java、JavaScript、C 等多种开发语言的包、依赖和环境管理工具，能运行在 Windows、MacOS、Linux 多个平台，可以在本地轻松创建、保存、切换环境。当安装 anaconda 时，会自动安装 conda 工具。

conda 与 pipenv，venv 等虚拟环境管理工具的最大的不同在于：conda 虚拟环境是独立于操作系统解释器环境的，即无论操作系统解释器什么版本（哪怕 2.7），我也可以指定虚拟环境 python 版本为 3.6，而 venv 是依赖主环境的。

conda_6">查看conda版本

$conda --version
conda 23.1.0

查看帮助信息

$conda --help
usage: conda-script.py [-h] [-V] command ...conda is a tool for managing and deploying applications, environments and packages.Options:positional arguments:commandclean             Remove unused packages and caches.compare           Compare packages between conda environments.config            Modify configuration values in .condarc. This is modeledafter the git config command. Writes to the user.condarc file (C:\Users\user\.condarc) by default. Usethe --show-sources flag to display all identifiedconfiguration locations on your computer.create            Create a new conda environment from a list of specifiedpackages.info              Display information about current conda install.init              Initialize conda for shell interaction.install           Installs a list of packages into a specified condaenvironment.list              List installed packages in a conda environment.package           Low-level conda package utility. (EXPERIMENTAL)remove (uninstall)Remove a list of packages from a specified condaenvironment.rename            Renames an existing environment.run               Run an executable in a conda environment.search            Search for packages and display associatedinformation.The input is a MatchSpec, a query languagefor conda packages. See examples below.update (upgrade)  Updates conda packages to the latest compatible version.notices           Retrieves latest channel notifications.options:-h, --help          Show this help message and exit.-V, --version       Show the conda version number and exit.

查看安装包列表

$ conda list                                                     
# packages in environment at D:\anaconda3:                       
#                                                                
# Name                    Version                   Build  Channe
adbutils                  2.8.0                    pypi_0    pypi
aiohttp                   3.8.5                    pypi_0    pypi
aiosignal                 1.3.1                    pypi_0    pypi
aiosqlite                 0.20.0                   pypi_0    pypi
alabaster                 0.7.16                   pypi_0    pypi
albucore                  0.0.13                   pypi_0    pypi
albumentations            1.4.10                   pypi_0    pypi
altair                    5.2.0                    pypi_0    pypi
......

配置下载源

以清华源为例

conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free/
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main/

还有很多其他的镜像：

conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free/
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main/
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/conda-forge/
conda config --add channels https://mirrors.tuna.tsinghua.edu.cn/anaconda/cloud/bioconda/
conda config --add channels https://mirrors.bfsu.edu.cn/anaconda/cloud/bioconda/
conda config --add channels https://mirrors.bfsu.edu.cn/anaconda/cloud/conda-forge/
conda config --add channels https://mirrors.bfsu.edu.cn/anaconda/pkgs/free/
conda config --add channels https://mirrors.bfsu.edu.cn/anaconda/pkgs/main/

查看配置结果：

$ conda config --show-sources                               
==> C:\Users\user\.condarc <==                             
ssl_verify: True                                            
channels:                                                   - https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main/- https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free/- defaults

配置显示下载源

conda config --set show_channel_urls yes

创建环境

conda create --name myenv python=3.8 requests

这里创建一个虚拟环境，名称是myenv，python版本是3.8，依赖库是requests。

激活环境

$ conda activate myenv

激活之后，命令行前面会显示(myenv)。

关闭环境

$ conda deactivate

查看所有的环境

(myenv) λ conda env list                        
# conda environments:                            
#                                                D:\Anaconda3            
base                     D:\anaconda3            
myenv                *  D:\anaconda3\envs\myenv

安装依赖包

(myenv) $conda install beautifulsoup4
Collecting package metadata (current_repodata.json): done
Solving environment: done==> WARNING: A newer version of conda exists. <==current version: 23.1.0latest version: 24.11.3Please update conda by running$ conda update -n base -c defaults condaOr to minimize the number of packages updated during conda update useconda install conda=24.11.3## Package Plan ##environment location: D:\anaconda3\envs\myenvadded / updated specs:- beautifulsoup4The following packages will be downloaded:package                    |            build---------------------------|-----------------beautifulsoup4-4.12.3      |   py38haa95532_0         214 KB  https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/mainsoupsieve-2.5              |   py38haa95532_0          70 KB  https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/main------------------------------------------------------------Total:         284 KBThe following NEW packages will be INSTALLED:beautifulsoup4     anaconda/pkgs/main/win-64::beautifulsoup4-4.12.3-py38haa95532_0soupsieve          anaconda/pkgs/main/win-64::soupsieve-2.5-py38haa95532_0Proceed ([y]/n)? yDownloading and Extracting PackagesPreparing transaction: done
Verifying transaction: done
Executing transaction: done

移除依赖包

conda remove beautifulsoup4

导出环境配置

conda env export > myenv.yml

删除环境

conda deactivate # 删除之前要先关闭当前环境
conda remove --name myenv --all

导入环境配置

conda env create -f myenv.yml