我知道pip是python包的包管理器。但是,我在IPython的网站上看到了使用conda安装IPython的安装。
我可以用pip安装IPython吗?当我已经有pip时,为什么我要使用conda作为另一个python包管理器?
pip和conda的区别是什么?
我知道pip是python包的包管理器。但是,我在IPython的网站上看到了使用conda安装IPython的安装。
我可以用pip安装IPython吗?当我已经有pip时,为什么我要使用conda作为另一个python包管理器?
pip和conda的区别是什么?
当前回答
免责声明:这个答案描述的是十年前的情况,当时pip还不支持二进制包。Conda是专门为更好地支持构建和分发二进制包而创建的,特别是带有C扩展的数据科学库。作为参考,pip只获得了带轮子的便携式二进制包的广泛支持(2013年的pip 1.4)和manylinux1规范(2016年3月的pip 8.1)。查看最近的答案了解更多历史。
以下是一个简短的概述:
pip
只支持Python包。 从源代码编译所有内容。编辑:pip现在安装二进制车轮,如果他们是可用的。 受到核心Python社区的支持(即Python 3.4+包含自动引导pip的代码)。
conda
Python agnostic. The main focus of existing packages are for Python, and indeed Conda itself is written in Python, but you can also have Conda packages for C libraries, or R packages, or really anything. Installs binaries. There is a tool called conda build that builds packages from source, but conda install itself installs things from already built Conda packages. External. conda is an environment and package manager. It is included in the Anaconda Python distribution provided by Continuum Analytics (now called Anaconda, Inc.).
conda is an environment manager written in Python and is language-agnostic. conda environment management functions cover the functionality provided by venv, virtualenv, pipenv, pyenv, and other Python-specific package managers. You could use conda within an existing Python installation by pip installing it (though this is not recommended unless you have a good reason to use an existing installation). As of 2022, conda and pip are not fully aware of one another package management activities within a virtual environment, not are they interoperable for Python package management.
在这两种情况下:
用Python编写 开源(conda是BSD, pip是MIT) 警告:虽然conda本身是开源的,但包存储库由Anaconda Inc托管,并且在商业使用方面有限制。
The first two bullet points of conda are really what make it advantageous over pip for many packages. Since pip installs from source, it can be painful to install things with it if you are unable to compile the source code (this is especially true on Windows, but it can even be true on Linux if the packages have some difficult C or FORTRAN library dependencies). conda installs from binary, meaning that someone (e.g., Continuum) has already done the hard work of compiling the package, and so the installation is easy.
如果您对构建自己的包感兴趣,也有一些不同之处。例如,pip构建在setuptools之上,而conda使用自己的格式,这有一些优点(比如是静态的,并且与Python无关)。
其他回答
引用Conda for Data Science在Continuum网站上的文章:
Conda vs pip Python programmers are probably familiar with pip to download packages from PyPI and manage their requirements. Although, both conda and pip are package managers, they are very different: Pip is specific for Python packages and conda is language-agnostic, which means we can use conda to manage packages from any language Pip compiles from source and conda installs binaries, removing the burden of compilation Conda creates language-agnostic environments natively whereas pip relies on virtualenv to manage only Python environments Though it is recommended to always use conda packages, conda also includes pip, so you don’t have to choose between the two. For example, to install a python package that does not have a conda package, but is available through pip, just run, for example:
conda install pip
pip install gensim
(2021更新)
使用pip,它是Python 3以来的官方包管理器。
pip
basics pip is the default package manager for python pip is built-in as of Python 3.0 Usage: python3 -m venv myenv; source myenv/bin/activate; python3 -m pip install requests Packages are downloaded from pypi.org, the official public python repository It can install precompiled binaries (wheels) when available, or source (tar/zip archive). Compiled binaries are important because many packages are mixed Python/C/other with third-party dependencies and complex build chains. They MUST be distributed as binaries to be ready-to-use. advanced pip can actually install from any archive, wheel, or git/svn repo... ...that can be located on disk, or on a HTTP URL, or a personal pypi server. pip install git+https://github.com/psf/requests.git@v2.25.0 for example (it can be useful for testing patches on a branch). pip install https://download.pytorch.org/whl/cpu/torch-1.9.0%2Bcpu-cp39-cp39-linux_x86_64.whl (that wheel is Python 3.9 on Linux). when installing from source, pip will automatically build the package. (it's not always possible, try building TensorFlow without the google build system :D) binary wheels can be python-version specific and OS specific, see manylinux specification to maximize portability.
conda
You are NOT permitted to use Anaconda or packages from Anaconda repositories for commercial use, unless you acquire a license. Conda is a third party package manager from conda. It's popularized by anaconda, a Python distribution including most common data science libraries ready-to-use. You will use conda when you use anaconda. Packages are downloaded from the anaconda repo. It only installs precompiled packages. Conda has its own format of packages. It doesn't use wheels. conda install to install a package. conda build to build a package. conda can build the python interpreter (and other C packages it depends on). That's how an interpreter is built and bundled for anaconda. conda allows to install and upgrade the Python interpreter (pip does not). advanced Historically, the selling point of conda was to support building and installing binary packages, because pip did not support binary packages very well (until wheels and manylinux2010 spec). Emphasis on building packages. Conda has extensive build settings and it stores extensive metadata, to work with dependencies and build chains. Some projects use conda to initiate complex build systems and generate a wheel, that is published to pypi.org for pip.
easy_install/鸡蛋
For historical reference only. DO NOT USE egg is an abandoned format of package, it was used up to mid 2010s and completely replaced by wheels. an egg is a zip archive, it contains python source files and/or compiled libraries. eggs are used with easy_install and the first releases of pip. easy_install was yet another package manager, that preceded pip and conda. It was removed in setuptools v58.3 (year 2021). it too caused a lot of confusion, just like pip vs conda :D egg files are slow to load, poorly specified, and OS specific. Each egg was setup in a separate directory, an import mypackage would have to look for mypackage.py in potentially hundreds of directories (how many libraries were installed?). That was slow and not friendly to the filesystem cache.
从历史上看,上述三个工具都是开源的,并且是用Python编写的。 然而,conda背后的公司在2020年更新了他们的服务条款,禁止商业使用,小心!
有趣的事实:构建Python解释器唯一严格要求的依赖项是zlib(一个zip库),因为压缩是加载更多包所必需的。鸡蛋和轮子包是zip文件。
为什么有这么多选择?
问得好。
让我们深入研究Python和计算机的历史。= D
纯python包总是能很好地与这些打包器一起工作。问题不仅在于python包。
世界上大多数的代码都依赖于C,这对于Python解释器来说是如此,它是用C编写的。对于许多Python包来说也是如此,这些包是围绕C库的Python包装器或混合了Python /C/ c++代码的项目。
任何涉及SSL、压缩、GUI (X11和Windows子系统)、数学库、GPU、CUDA等的东西……通常与一些C代码相结合。
这给打包和分发Python库带来了麻烦,因为不仅仅是Python代码可以在任何地方运行。库必须编译,编译需要编译器、系统库和第三方库,然后一旦编译,生成的二进制代码只适用于特定的系统和python版本。
最初,python可以很好地分发纯python库,但是很少支持分发二进制库。在2010年前后,您尝试使用numpy或cassandra时会遇到很多错误。它下载了源代码,但是由于缺少依赖项而无法编译。或者它下载了一个预构建的包(当时可能是一个egg),在使用时崩溃并发生SEGFAULT,因为它是为另一个系统构建的。这简直是一场噩梦。
从2012年开始,pip和wheels解决了这个问题。然后等待许多年,让人们采用这些工具,并让这些工具传播到稳定的Linux发行版(许多开发人员依赖/usr/bin/python)。二进制包的问题一直延续到2010年代末。
作为参考,这就是为什么要运行的第一个命令是python3 -m venv myvenv && source myvenv/bin/activate && pip install -upgrade pip setuptools在旧系统上,因为操作系统自带的是5年前的旧python+pip,它有bug,不能识别当前的包格式。
Conda并行地研究他们自己的解决方案。Anaconda专门用于使数据科学库易于开箱即用(数据科学= C和c++无处不在),因此他们必须提出一个专门用于构建和分发二进制包的包管理器conda。
如果你现在安装任何带有pip install xxx的软件包,它都可以工作。这是推荐的安装包的方式,并且在当前版本的Python中是内置的。
WINDOWS用户
“标准”包装工具的情况最近有所改善:
截至2015年9月11日,pypi本身的车轮包装数量为48%(2015年5月为38%,2014年9月为24%), 最新的python 2.7.9版本现在支持开箱即用的wheel格式,
“标准”+“微调”包装工具的情况也在改善:
你可以在http://www.lfd.uci.edu/~gohlke/pythonlibs上找到几乎所有的科学软件包, mingwpy项目可能有一天会给Windows用户带来一个“编译”包,允许他们在需要的时候从源代码安装所有东西。
“Conda”包装对于它所服务的市场来说仍然更好,并强调了“标准”应该改进的地方。
(此外,在标准wheel系统和conda系统或buildout中的依赖规范multiple-effort不是很python化,如果所有这些打包“核心”技术可以通过某种PEP聚合在一起就好了)
I may have found one further difference of a minor nature. I have my python environments under /usr rather than /home or whatever. In order to install to it, I would have to use sudo install pip. For me, the undesired side effect of sudo install pip was slightly different than what are widely reported elsewhere: after doing so, I had to run python with sudo in order to import any of the sudo-installed packages. I gave up on that and eventually found I could use sudo conda to install packages to an environment under /usr which then imported normally without needing sudo permission for python. I even used sudo conda to fix a broken pip rather than using sudo pip uninstall pip or sudo pip --upgrade install pip.
为了不让你们更困惑, 但是你也可以在conda环境中使用PIP,它会验证上面的一般管理器注释和特定于python的管理器注释。
conda install -n testenv pip
source activate testenv
pip <pip command>
您还可以将PIP添加到任何环境的默认包中,以便每次都显示它,这样您就不必遵循上面的代码段。