What is a dependency specification

Project dependencies can be specified in various forms, depending on the type of dependency and the optional constraints that might be required to install the project

Version constraint

^ constraints

Write specifications Allowed version range
^ 1.2.3 > = 1.2.3 < 2.0.0
^ 1.2 > = 1.2.0 < 2.0.0
^ 1 > = 1.0.0 < 2.0.0
^ 0.2.3 > = 0.2.3 < 0.3.0
^ 0.0.3 > = 0.0.3 < 0.0.4
^ 0.0 > = 0.0.0 < 0.1.0 from
^ 0 > = 0.0.0 < 1.0.0
  • If the leftmost number is not 0, the leftmost number is the major version number. For example, ^2.13.0 can be 2.14.0, but cannot be 3.0.0, because the major version number has changed
  • If the first digit on the left is 0, the second digit on the left is the main version number. For example, ^0.1.0 can be 0.1.1 or 0.1.19, but cannot be 0.2.0 because the main version number has changed

~ constraints

Write specifications Allowed version range
~ 1.2.3 > = 1.2.3 < 1.3.0
~ 1.2 > = 1.2.0 < 1.3.0
~ 1 > = 1.0.0 < 2.0.0

Similar to ^ above, but this is a minor version, based on the second number. Finally, if your time is not very tight, and want to quickly improve, the most important thing is not afraid of hardship, I suggest you can price @762459510, that is really very good, many people progress quickly, need you not afraid of hardship oh! You can go to add a look at ~

* constraint

It’s kind of like a universal card, you can write it anywhere, right

Write specifications Allowed version range
* > = 0.0.0
1. * > = 1.0.0 < 2.0.0
1.2. * > = 1.2.0 < 1.3.0

Comparison operators

The normal > and < symbols

>= 1.2.0
> 1
< 2
!= 1.2.3
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A defined version number or scope

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>= 1.2, < 1.5Copy the code

Git is dependent on

You can specify a Git repository address for dependencies

[tool.poetry.dependencies]
requests = { git = "https://github.com/requests/requests.git" }
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The default is to pull the Master branch of the Git repository

You can also specify branch, commit hash, or tag

[tool.poetry.dependencies] # Get the latest revision on the branch named "next" requests = { git = "https://github.com/kennethreitz/requests.git", branch = "next" } # Get a revision by its commit hash flask = { git = "https://github.com/pallets/flask.git", Rev = "38 eb5d3b"} # Get a revision by its tag numpy = {git = "https://github.com/numpy/numpy.git", tag = "v0.13.2}"Copy the code

Path dependence

If the dependency is in a local directory, you can use path

[tool.poetry.dependencies] # directory my-package = { path = ".. /my-package/", develop = false } # file my-package = { path = ".. / my - package/dist/my - package - 0.1.0 from. Tar. Gz "}Copy the code

Url to rely on

If you rely on files from a remote repository, use urls

[tool.poetry. Dependencies] # directory my-package = {url = "https://example.com/my-package-0.1.0.tar.gz"}Copy the code

You can add urls via poetry Add

Poetry add https://example.com/my-package-0.1.0.tar.gzCopy the code

Python restricts dependencies

Specifies that dependencies should only be installed with a particular Python version

[tool.poetry. Dependencies] pathlib2 = {version = "^2.2", python = "~2.7"}Copy the code
[tool. Poetry. Dependencies] pathlib2 = {version = "2.2" ^, python = "~ 2.7 | | ^ 3.2"}Copy the code

Multiple restrictions

Hypothetical dependency package

Python 2.7 to Python 2.9 is compatible only with versions 1.9 or smaller

Versions greater than 2.0 are only compatible with Python 3.4 +

[tool. Poetry. Dependencies] foo = [{version = "< = 1.9," python = "^ 2.7"}, {version = "^ 2.0," python = "^ 3.4"}]Copy the code

Use environment Restriction

Feel less use, not to expand the detailed explanation

[tool.poetry. Dependencies] pathlib2 = {version = "^2.2", Markers = "python_version ~= '2.7' or sys_platform == 'win32'"}Copy the code

Markers of official document: www.python.org/dev/peps/pe…

Extensions rely on canonical syntax

When a dependency requires many attributes, the readability is poor, as shown below

[tool.poetry. Dev-dependencies] black = {version = "19.10b0", allow-prereleases = true, python = "^3.6", markers = "platform_python_implementation == 'CPython'"}Copy the code

Use the new syntax format

[tool.poetry. Dev-dependencies. Black] version = "19.10b0" allow-prereleases = true python = "^3.6" markers = "platform_python_implementation == 'CPython'"Copy the code

The constraints of dependencies are exactly the same, but become a row of constraint attributes, which is more readable. Finally, if your time is not very tight, and want to quickly improve, the most important thing is not afraid of hardship, I suggest you can price @762459510, that is really very good, many people progress quickly, need you not afraid of hardship oh! You can go to add a look at ~

This is the Python dependency management and packaging tool Poetry dependency specification. For more information about the Python tool Poetry dependency specification, check out other related articles.

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