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
pip仅用于Python
conda只适用于Anaconda +其他科学包,如R依赖等。并不是每个人都需要蟒蛇,因为它已经和Python一起出现了。Anaconda主要是为那些做机器学习/深度学习等的人准备的。普通的Python开发人员不会在他的笔记本电脑上运行Anaconda。
其他回答
引用Conda: Myths and misconcepts(一个全面的描述):
...
误解3:Conda和pip是直接竞争对手
事实:Conda和pip服务于不同的目的,并且只在一小部分任务上直接竞争:即在孤立的环境中安装Python包。
Pip是Pip安装包的缩写,是Python官方认可的包管理器,最常用于安装发布在Python包索引(PyPI)上的包。pip和PyPI都由Python打包管理局(PyPA)管理和支持。
In short, pip is a general-purpose manager for Python packages; conda is a language-agnostic cross-platform environment manager. For the user, the most salient distinction is probably this: pip installs python packages within any environment; conda installs any package within conda environments. If all you are doing is installing Python packages within an isolated environment, conda and pip+virtualenv are mostly interchangeable, modulo some difference in dependency handling and package availability. By isolated environment I mean a conda-env or virtualenv, in which you can install packages without modifying your system Python installation.
Even setting aside Myth #2, if we focus on just installation of Python packages, conda and pip serve different audiences and different purposes. If you want to, say, manage Python packages within an existing system Python installation, conda can't help you: by design, it can only install packages within conda environments. If you want to, say, work with the many Python packages which rely on external dependencies (NumPy, SciPy, and Matplotlib are common examples), while tracking those dependencies in a meaningful way, pip can't help you: by design, it manages Python packages and only Python packages.
Conda和pip不是竞争对手,而是专注于不同用户组和使用模式的工具。
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)
这个答案来自于上面@user5994461的答案
您可以使用pip进行包管理。自Python 3以来,Pip是Python.org的官方内置包管理器。
PIP不是虚拟环境管理器。
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
conda is an open source environment manager AND package manager maintained by the open source community. It is separate from Anaconda, Inc. and does not require a commercial license to use. conda is also bundled into Anaconda Navigator, a popular commercial Python distribution from Anaconda, Inc. Anaconda) that includes most common data science and Python developer libraries ready-to-use. You will use conda when you use Anaconda Navigator GUI. Packages may be downloaded from conda-forge, anaconda repo4, and other public and private conda package "channels" (aka repos). It only installs precompiled packages. conda has its own package format. 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 Navigator. conda allows to install and upgrade the Python interpreter (pip does not). advanced Historically, one 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. conda emphasizes building and managing virtual environments. conda is by design a programming language-agnostic virtual environment manager. conda can install and manage other package managers such as npm, pip, and other language package managers. Can I use Anaconda Navigator packages for commercial use? The new language states that use by individual hobbyists, students, universities, non-profit organizations, or businesses with less than 200 employees is allowed, and all other usage is considered commercial and thus requires a business relationship with Anaconda. (as of Oct 28, 2020) IF you are a large developer organization, i.e., greater than 200 employees, you are NOT permitted to use Anaconda or packages from Anaconda repository for commercial use, unless you acquire a license. Pulling and using (properly open-sourced) packages from conda-forge repository do not require commercial licenses from Anaconda, Inc. Developers are free to build their own conda packages using the packaging tools provided in the conda-forge infrastructure.
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.
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。
Continuum Analytics(后来更名为Anaconda, Inc.)并行开发他们自己的解决方案(发布为Anaconda Navigator)。Anaconda Navigator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),因此他们提出了一个专门用于构建和分发二进制包的包管理器,并将其构建到环境管理器conda中。
如果你现在安装任何带有pip install xxx的软件包,它通常都能正常工作。pip是安装内置到当前版本Python中的包的推荐方法。
要回答最初的问题, 对于安装包,PIP和Conda是完成相同任务的不同方式。两者都是安装包的标准应用程序。主要的区别是包文件的来源。
PIP/PyPI将有更多的“实验性”包,或者更新的、不太常见的包版本 Conda通常会有更完善的包或版本
一个重要的警告提示:如果使用两个源(pip和conda)在同一环境中安装包,以后可能会导致问题。
重建环境将更加困难 修复包不兼容性变得更加复杂
最佳实践是选择一个应用程序(PIP或Conda)来安装包,并使用该应用程序安装所需的任何包。 然而,仍然有许多例外或理由在conda环境中使用pip,反之亦然。 例如:
如果您需要的包只存在于一个包上,则 其他人没有。 您需要一个只在一个环境中可用的特定版本
PIP是一个包管理器。
Conda既是包管理器,也是环境管理器。
细节:
依赖项检查
Pip and conda also differ in how dependency relationships within an environment are fulfilled. When installing packages, pip installs dependencies in a recursive, serial loop. No effort is made to ensure that the dependencies of all packages are fulfilled simultaneously. This can lead to environments that are broken in subtle ways, if packages installed earlier in the order have incompatible dependency versions relative to packages installed later in the order. In contrast, conda uses a satisfiability (SAT) solver to verify that all requirements of all packages installed in an environment are met. This check can take extra time but helps prevent the creation of broken environments. As long as package metadata about dependencies is correct, conda will predictably produce working environments.
参考文献
理解康达和皮普